Intermittent Fasting Promotes Weight Loss without Decreasing Performance in Taekwondo

Intermittent fasting (IF) is commonly used by combat sports athletes for weight loss. However, IF can decrease performance. This study aimed to investigate the effect of IF on total body mass (TBM) and Taekwondo performance. Nine athletes (seven male, two female; 18.4 ± 3.3 years) underwent 4 weeks of 12 h IF. TBM, countermovement jump (CMJ), mean kicks (MK), and total number of kicks (TNK) were compared weekly. Performance was measured in the fed state (FED) and fast state (FAST). Results showed decreased TBM in week 1 (62.20 ± 6.56 kg; p = 0.001) and week 2 (62.38 ± 6.83 kg; p = 0.022) compared to pre-intervention (63.58 ± 6.57 kg), stabilizing in week 3 (62.42 ± 6.12 kg), and no significant change in week 4 (63.36 ± 6.20 kg). CMJ performance in week 1 was lower in FED (35.26 ± 7.15 cm) than FAST (37.36 ± 6.77 cm; p = 0.003), but in week 3, FED (38.24 ± 6.45 cm) was higher than FAST (35.96 ± 5.05 cm; p = 0.047). No significant differences were found in MK and TNK in FSKTmult. RPE, KDI, and HR were similar between FED and FAST (p < 0.05). [LAC] was higher post-test compared to pre-test (p = 0.001), with higher concentrations in FED than FAST (p = 0.020). BG was higher in FED than FAST (p < 0.05) before physical tests. Therefore, IF promotes decreased TBM without decreasing performance.


Introduction
In combat sports, there are numerous strategies for rapid reduction of total body mass (TBM), such as water restriction, use of laxatives, immersion in hot water baths, sauna sessions, increased quantity and duration of training sessions, and performing exercises with heavy clothing and/or plastic suits [1]. However, these strategies can lead to detrimental effects on athletic performance, including muscle mass reduction, decreased overall and specific endurance, impaired training adaptations, decreased concentration capacity, difficulty in decision-making, mood alterations such as increased irritability and demotivation, and increased discomfort and subjective perception of effort following training sessions [2]. Therefore, the adoption of nutritional strategies such as hypocaloric diets and intermittent fasting can be less harmful alternatives for reducing body mass in this population. During the six weeks, the athletes' food intake was recorded weekly over thr consecutive days [19], followed by a supplementary dietary recall [20], to meas total calories ingested and the macronutrient composition. Prior to the beginning study, the volunteers received explanations and training to record their food intak homemade measures and photographic records. The supplementary dietary rec performed based on the weekly food intake record to identify possible errors in t cess carried out by the volunteers, such as food and meal identifications, homemad urements, and timing. Each week, the dietary profile of each volunteer was dete using the supplementary dietary recall, which was adopted to monitor and comp nutritional intake between the weeks of the experimental intervention. The dietary The CMJ and the FSKTmult tests were performed. All athletes answered the rating of perceived exertion (RPE) at the end of the test sessions. The lactate concentration [LAC] was measured pre-and two minutes post-FSKTmult using an Accutrend Plus lactometer (Roche Diagnostics, Brazil Ltda., Sao Paulo, Brazil). To avoid performing the tests in a state of hypoglycemia and to verify whether the athletes were in the FED or FAST state, we measured the values of both pre-and post-test blood glucose [BG] concurrently with lactate [LAC] using a FreeStyle Optium Neo glucometer (Abbott Laboratórios do Brasil Ltda., Rio de Janeiro, Brazil). The training frequency of the athletes reached six sessions per week throughout the six weeks. Five sessions were performed from Monday to Friday in the afternoon (2:00 p.m.), with a 24 h interval between sessions. The sixth training session took place on a Saturday morning (8:00 a.m.), with a 14 h interval from the Friday training session.
The IF protocol applied over the four-week intervention consisted of 12 h of timerestricted feeding, starting at night, with breakfast omission, interspersed with periods of non-restricted feeding. The volunteers were instructed to maintain their eating habits during the feeding period, and no nutrition intervention was performed. On days of testing in the fed state, the pre-workout meal was consumed between 1 to 2 h before the start of the tests.
During the six weeks, the athletes' food intake was recorded weekly over three nonconsecutive days [19], followed by a supplementary dietary recall [20], to measure the total calories ingested and the macronutrient composition. Prior to the beginning of the study, the volunteers received explanations and training to record their food intake using homemade measures and photographic records. The supplementary dietary recall was performed based on the weekly food intake record to identify possible errors in the process carried out by the volunteers, such as food and meal identifications, homemade measurements, and timing. Each week, the dietary profile of each volunteer was determined using the supplementary dietary recall, which was adopted to monitor and compare the nutritional intake between the weeks of the experimental intervention. The dietary profile was determined based on the daily total caloric intake and the intake of macronutrients: carbohydrates, lipids, and proteins. All values were normalized by TBM. These procedures were performed using the DietBox app (Dietbox Informática Ltda., version 7.8.1, Porto Alegre, Brazil) and the following tables, in order of preference: the Brazilian

Familiarization and Reliability
The athletes participated in two familiarization sessions in the first week and two reliability sessions in the second week, respecting a 48 h interval. In each session, we applied a sequence of two sets of eight CMJs with a one-minute interval between jumps and 10 min between the sets. If in a single session, the first and second sets presented a statistically significant difference, then an addition set with eight CMJs was performed until two consecutive sets showed no statistically significant difference [21]. Familiarization was considered successful when there was no statistically significant difference between the means of jump heights in two consecutive sessions [21]. All sessions were performed using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 1000 Hz with 1 N accuracy).
The FSKTmult test was applied ten minutes after the CMJ test and encompassed three rounds of five sets with 10 s of stimuli, 10 s of interval rest between sets, and a oneminute interval between rounds [7]. The test was conducted using Boomboxe ® (Simulacare, São Paulo, Brazil), and the athletes were instructed to perform the maximum number of kicks possible. During the FSKTmult test, all athletes used a heart rate sensor (Polar H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have both the mean (HRmed) and maximum (HRmax) heart rates measured, and at the end of the test, they answered the RPE immediately. The performance analysis involved registering the total number of kicks (TNK) and the mean of kicks performed (MK) during three rounds. Additionally, the kick decrease index (KDI) was calculated using the following equation proposed by Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes in FED (Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with a one-Nutrients 2023, 15, 3131 5 of 12 minute interval rest between them. Ten minutes later, the FSKTmult test was performed following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last training session, whereas the tests in FAST took place on Saturdays after the 14 h rest interval from the Friday training session (Figure 1). For the tests in FAST, the athletes were instructed to have their last meal of the day 12 h before. The same test sessions and procedures as the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a digital scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To prevent potential small, systematic, and predictable errors due to changes in the balance of body fluids, the athletes were instructed not to ingest large amounts of water, to urinate at least 30 min before, and not to consume alcoholic beverages or perform any physical exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk and Mauchly tests. If neither the normality nor the sphericity assumptions were met, nonparametric tests and the Greenhouse-Geisser correction were applied. The stabilization of both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA ( best FSKT × number of sets ] × 100 (1)

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes in FED (Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with a oneminute interval rest between them. Ten minutes later, the FSKTmult test was performed following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last training session, whereas the tests in FAST took place on Saturdays after the 14 h rest interval from the Friday training session (Figure 1). For the tests in FAST, the athletes were instructed to have their last meal of the day 12 h before. The same test sessions and procedures as the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a digital scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To prevent potential small, systematic, and predictable errors due to changes in the balance of body fluids, the athletes were instructed not to ingest large amounts of water, to urinate at least 30 min before, and not to consume alcoholic beverages or perform any physical exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk and Mauchly tests. If neither the normality nor the sphericity assumptions were met, non-parametric tests and the Greenhouse-Geisser correction were applied. The stabilization of both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0. (1)

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes in FED ( Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with a oneminute interval rest between them. Ten minutes later, the FSKTmult test was performed following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last training session, whereas the tests in FAST took place on Saturdays after the 14 h rest interval from the Friday training session (Figure 1). For the tests in FAST, the athletes were instructed to have their last meal of the day 12 h before. The same test sessions and procedures as the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a digital scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To prevent potential small, systematic, and predictable errors due to changes in the balance of body fluids, the athletes were instructed not to ingest large amounts of water, to urinate at least 30 min before, and not to consume alcoholic beverages or perform any physical exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk and Mauchly tests. If neither the normality nor the sphericity assumptions were met, non-parametric tests and the Greenhouse-Geisser correction were applied. The stabilization of both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0.

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes in F ( Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with a o minute interval rest between them. Ten minutes later, the FSKTmult test was perform following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last train session, whereas the tests in FAST took place on Saturdays after the 14 h rest interval fr the Friday training session (Figure 1). For the tests in FAST, the athletes were instruc to have their last meal of the day 12 h before. The same test sessions and procedures the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a dig scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To p vent potential small, systematic, and predictable errors due to changes in the balance body fluids, the athletes were instructed not to ingest large amounts of water, to urin at least 30 min before, and not to consume alcoholic beverages or perform any phys exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk a Mauchly tests. If neither the normality nor the sphericity assumptions were met, non-p ametric tests and the Greenhouse-Geisser correction were applied. The stabilization both the CMJ and FSKTmult tests during the familiarization sessions was analyz through the paired student t-test [21]. Reliability was verified by a two-way mixed int class correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures w applied for the TBM regarding the amount of calories ingested and the proportion of m ronutrients throughout the weeks. This procedure (time x situation) was used to comp the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] a [LAC] in different situations were analyzed through a three-way ANOVA with repea measures (week x situation x moment). Bonferroni's post hoc test was used to iden where differences occurred. The Cohen's d effect size for paired samples was verif based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectiv [24,25]. All data are presented as mean, standard deviation, and 95% confidence inter (CI95%). All analyses considered a significance level of α = 0.05. All statistical analy were performed on SPSS version 20.0.

Performance Protocols
The BL was performed 48 h after the last reliability sessi ( Figure 1). The CMJ height in BL was assessed by applying a minute interval rest between them. Ten minutes later, the FS following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, session, whereas the tests in FAST took place on Saturdays aft the Friday training session (Figure 1). For the tests in FAST, to have their last meal of the day 12 h before. The same test the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays a vent potential small, systematic, and predictable errors due t body fluids, the athletes were instructed not to ingest large a at least 30 min before, and not to consume alcoholic beverag exercise within 24 h other than the Taekwondo training sessio

Statistical Analysis
The normality and sphericity of the data were verified u Mauchly tests. If neither the normality nor the sphericity assu ametric tests and the Greenhouse-Geisser correction were a both the CMJ and FSKTmult tests during the familiarizat through the paired student t-test [21]. Reliability was verified class correlation coefficient (ICC) [23]. A two-way ANOVA w applied for the TBM regarding the amount of calories ingested ronutrients throughout the weeks. This procedure (time x situ the performance variables (CMJ, TNK, MK, HRmed, HRma [LAC] in different situations were analyzed through a three-w measures (week x situation x moment). Bonferroni's post ho where differences occurred. The Cohen's d effect size for p based on the partial ETA (ŋp 2 ) square. The effect size was co large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0 [24,25]. All data are presented as mean, standard deviation, a (CI95%). All analyses considered a significance level of α = were performed on SPSS version 20.0. p 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0.
The reliability test for the CMJ found a significant and excellent correlation (ICC = 0.97; p = 0.001; CI95% = 0.90-0.99) between the jumps of the first (37.47 ± 5.93 cm) and second sessions (37.20 ± 6.48 cm). The FSKTmult indicated a significant correlation to the mean number of total kicks in the first session (89.00 ± 8.2), ranked as good (ICC = 0.89; p = 0.001; CI95% = 0.57-0.97) compared with the mean number of total kicks in the second session (91.11 ± 6.67).

Total Body Mass
The TBM decreased with a large effect size throughout the weeks (F(4) = 7.120; p = 0.006; both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).

CMJ
No difference was indicated regarding the CMJ either between the intervention weeks (F(3) = 1.232; p = 0.320; kicks (TNK) and the mean of kicks performed (MK) during three rounds. Additionally, the kick decrease index (KDI) was calculated using the following equation proposed by Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes in FED ( Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with a oneminute interval rest between them. Ten minutes later, the FSKTmult test was performed following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last training session, whereas the tests in FAST took place on Saturdays after the 14 h rest interval from the Friday training session (Figure 1). For the tests in FAST, the athletes were instructed to have their last meal of the day 12 h before. The same test sessions and procedures as the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a digital scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To prevent potential small, systematic, and predictable errors due to changes in the balance of body fluids, the athletes were instructed not to ingest large amounts of water, to urinate at least 30 min before, and not to consume alcoholic beverages or perform any physical exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk and Mauchly tests. If neither the normality nor the sphericity assumptions were met, non-parametric tests and the Greenhouse-Geisser correction were applied. The stabilization of both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0. p 2 = 0.13) or between situations (F(2) = 0.994; p = 0.392; kicks (TNK) and the mean of kicks pe the kick decrease index (KDI) was cal Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after ( Figure 1). The CMJ height in BL was a minute interval rest between them. Te following the same familiarization pro The test sessions in FED were co session, whereas the tests in FAST took the Friday training session (Figure 1). to have their last meal of the day 12 h the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST scale (Welmy ® , Santa Bárbara d'Oeste vent potential small, systematic, and p body fluids, the athletes were instruct at least 30 min before, and not to con exercise within 24 h other than the Tae

Statistical Analysis
The normality and sphericity of t Mauchly tests. If neither the normality ametric tests and the Greenhouse-Ge both the CMJ and FSKTmult tests d through the paired student t-test [21]. class correlation coefficient (ICC) [23]. applied for the TBM regarding the amo ronutrients throughout the weeks. Thi the performance variables (CMJ, TNK [LAC] in different situations were ana measures (week x situation x momen where differences occurred. The Coh based on the partial ETA (ŋp 2 ) square large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 [24,25]. All data are presented as mean (CI95%). All analyses considered a si were performed on SPSS version 20.0. p 2 = 0.11). However, there was a difference in the week x situation interaction, with a large effect size (F(6) = 7.040; p = 0.001; maximum (HRmax) heart rates measured, and at the end of the test, they answered the RPE immediately. The performance analysis involved registering the total number of kicks (TNK) and the mean of kicks performed (MK) during three rounds. Additionally, the kick decrease index (KDI) was calculated using the following equation proposed by Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes in FED ( Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with a oneminute interval rest between them. Ten minutes later, the FSKTmult test was performed following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last training session, whereas the tests in FAST took place on Saturdays after the 14 h rest interval from the Friday training session (Figure 1). For the tests in FAST, the athletes were instructed to have their last meal of the day 12 h before. The same test sessions and procedures as the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a digital scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To prevent potential small, systematic, and predictable errors due to changes in the balance of body fluids, the athletes were instructed not to ingest large amounts of water, to urinate at least 30 min before, and not to consume alcoholic beverages or perform any physical exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk and Mauchly tests. If neither the normality nor the sphericity assumptions were met, non-parametric tests and the Greenhouse-Geisser correction were applied. The stabilization of both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0. p 2 = 0.46). The BonFerroni posthoc test detected a difference in the FED compared with the BL (p = 0.049; 95%CI = 0.01-3.33) concerning the FAST (p = 0.003; 95%CI = −3.33, −0.87) in the first week; however, no difference was found in the second week. In the third week, the BonFerroni posthoc test detected a difference between the FED and FAST (p = 0.047; 95%CI = 0.03, 4.52), whereas in the fourth week, a difference between the situations was found. Furthermore, the CMJ for the FED in the third week was higher than that in the first week (p = 0.032; 95%CI = −5.72, −0.24), which also occurred for the fourth week compared with the first week (p = 0.050; 95%CI = −5.37, 0.01). Table 1 shows the respective results.

FSKTmult
The results of the FSKTmult test indicated no difference in the MK or the TNK between the weeks (F(3) = 3.744; p = 0.074; Nutrients 2023, 15, x FOR PEER REVIEW the means of jump heights in two consecutive sessions [21]. All sessions we using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 1000 Hz with 1 N a The FSKTmult test was applied ten minutes after the CMJ test and three rounds of five sets with 10 s of stimuli, 10 s of interval rest between se minute interval between rounds [7]. The test was conducted using Boom lacare, São Paulo, Brazil), and the athletes were instructed to perform the ma ber of kicks possible. During the FSKTmult test, all athletes used a heart rate H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have both the mean maximum (HRmax) heart rates measured, and at the end of the test, they RPE immediately. The performance analysis involved registering the tot kicks (TNK) and the mean of kicks performed (MK) during three rounds. the kick decrease index (KDI) was calculated using the following equation Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with the at (Figure 1). The CMJ height in BL was assessed by applying a set of five jump minute interval rest between them. Ten minutes later, the FSKTmult test w following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the session, whereas the tests in FAST took place on Saturdays after the 14 h rest the Friday training session (Figure 1). For the tests in FAST, the athletes w to have their last meal of the day 12 h before. The same test sessions and p the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly u scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the vent potential small, systematic, and predictable errors due to changes in t body fluids, the athletes were instructed not to ingest large amounts of wa at least 30 min before, and not to consume alcoholic beverages or perform exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shap Mauchly tests. If neither the normality nor the sphericity assumptions were ametric tests and the Greenhouse-Geisser correction were applied. The st both the CMJ and FSKTmult tests during the familiarization sessions w through the paired student t-test [21]. Reliability was verified by a two-way class correlation coefficient (ICC) [23]. A two-way ANOVA with repeated m applied for the TBM regarding the amount of calories ingested and the prop ronutrients throughout the weeks. This procedure (time x situation) was use the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and K [LAC] in different situations were analyzed through a three-way ANOVA measures (week x situation x moment). Bonferroni's post hoc test was us where differences occurred. The Cohen's d effect size for paired samples based on the partial ETA (ŋp 2 ) square. The effect size was considered smal large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64 [24,25]. All data are presented as mean, standard deviation, and 95% confid (CI95%). All analyses considered a significance level of α = 0.05. All statis were performed on SPSS version 20.0. the means of jump heights in two consecutive sessions [21]. All sessions were performed using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 1000 Hz with 1 N accuracy). The FSKTmult test was applied ten minutes after the CMJ test and encompassed three rounds of five sets with 10 s of stimuli, 10 s of interval rest between sets, and a oneminute interval between rounds [7]. The test was conducted using Boomboxe ® (Simulacare, São Paulo, Brazil), and the athletes were instructed to perform the maximum number of kicks possible. During the FSKTmult test, all athletes used a heart rate sensor (Polar H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have both the mean (HRmed) and maximum (HRmax) heart rates measured, and at the end of the test, they answered the RPE immediately. The performance analysis involved registering the total number of kicks (TNK) and the mean of kicks performed (MK) during three rounds. Additionally, the kick decrease index (KDI) was calculated using the following equation proposed by Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes in FED ( Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with a oneminute interval rest between them. Ten minutes later, the FSKTmult test was performed following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last training session, whereas the tests in FAST took place on Saturdays after the 14 h rest interval from the Friday training session (Figure 1). For the tests in FAST, the athletes were instructed to have their last meal of the day 12 h before. The same test sessions and procedures as the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a digital scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To prevent potential small, systematic, and predictable errors due to changes in the balance of body fluids, the athletes were instructed not to ingest large amounts of water, to urinate at least 30 min before, and not to consume alcoholic beverages or perform any physical exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk and Mauchly tests. If neither the normality nor the sphericity assumptions were met, non-parametric tests and the Greenhouse-Geisser correction were applied. The stabilization of both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0. The FSKTmult test was a three rounds of five sets with 1 minute interval between roun lacare, São Paulo, Brazil), and t ber of kicks possible. During th H10, Polar Electro Brasil, Ltda maximum (HRmax) heart rate RPE immediately. The perform kicks (TNK) and the mean of k the kick decrease index (KDI) Santos and Franchini [22].

Performance Protocols
The BL was performed 48 ( Figure 1). The CMJ height in B minute interval rest between th following the same familiarizat The test sessions in FED session, whereas the tests in FA the Friday training session (Fig  to have their last meal of the d the BL were applied.

Total Body Mass Measures
The TBM was measured in scale (Welmy ® , Santa Bárbara d vent potential small, systemati body fluids, the athletes were i at least 30 min before, and not exercise within 24 h other than

Statistical Analysis
The normality and spheri Mauchly tests. If neither the no ametric tests and the Greenho both the CMJ and FSKTmult through the paired student t-te class correlation coefficient (IC applied for the TBM regarding ronutrients throughout the wee the performance variables (CM [LAC] in different situations w measures (week x situation x where differences occurred. T based on the partial ETA (ŋp 2 ) large if d = 0.20 or ŋp 2 = 0.04, d [24,25]. All data are presented (CI95%). All analyses consider were performed on SPSS versio p 2 = 0.20) ( Table 2). Compared with the BL, the results of RPE showed significantly higher values (p = 0.020) in the FAST for the second week, the FAST and FED for the third week, and the FAST and FED for the fourth week. Additionally, the RPE in the fourth week was higher than the BL (p = 0.001), as well as in the second (p = 0.033) and third weeks (p = 0.010), with a large effect size ( Nutrients 2023, 15, x FOR PEER REVIEW the means of jump heights in two consecutive sessions [21]. All sessions were using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 1000 Hz with 1 N accu The FSKTmult test was applied ten minutes after the CMJ test and enc three rounds of five sets with 10 s of stimuli, 10 s of interval rest between sets, minute interval between rounds [7]. The test was conducted using Boombo lacare, São Paulo, Brazil), and the athletes were instructed to perform the maxim ber of kicks possible. During the FSKTmult test, all athletes used a heart rate se H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have both the mean (HR maximum (HRmax) heart rates measured, and at the end of the test, they ans RPE immediately. The performance analysis involved registering the total kicks (TNK) and the mean of kicks performed (MK) during three rounds. Ad the kick decrease index (KDI) was calculated using the following equation pr Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with the athle (Figure 1). The CMJ height in BL was assessed by applying a set of five jumps w minute interval rest between them. Ten minutes later, the FSKTmult test was following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the la session, whereas the tests in FAST took place on Saturdays after the 14 h rest int the Friday training session (Figure 1). For the tests in FAST, the athletes were to have their last meal of the day 12 h before. The same test sessions and pro the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly usin scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tes vent potential small, systematic, and predictable errors due to changes in the body fluids, the athletes were instructed not to ingest large amounts of water at least 30 min before, and not to consume alcoholic beverages or perform an exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro Mauchly tests. If neither the normality nor the sphericity assumptions were me ametric tests and the Greenhouse-Geisser correction were applied. The stab both the CMJ and FSKTmult tests during the familiarization sessions was through the paired student t-test [21]. Reliability was verified by a two-way m class correlation coefficient (ICC) [23]. A two-way ANOVA with repeated me applied for the TBM regarding the amount of calories ingested and the proport ronutrients throughout the weeks. This procedure (time  The FSKTmult test was applied ten minutes after t three rounds of five sets with 10 s of stimuli, 10 s of interv minute interval between rounds [7]. The test was condu lacare, São Paulo, Brazil), and the athletes were instructed ber of kicks possible. During the FSKTmult test, all athletes H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to hav maximum (HRmax) heart rates measured, and at the end RPE immediately. The performance analysis involved r kicks (TNK) and the mean of kicks performed (MK) duri the kick decrease index (KDI) was calculated using the fo Santos and Franchini [22].
best FSKT × number of sets

Performance Protocols
The BL was performed 48 h after the last reliability s (Figure 1). The CMJ height in BL was assessed by applying minute interval rest between them. Ten minutes later, the following the same familiarization procedures.
The test sessions in FED were conducted on Monda session, whereas the tests in FAST took place on Saturdays the Friday training session (Figure 1). For the tests in FAS to have their last meal of the day 12 h before. The same t the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) a scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturda vent potential small, systematic, and predictable errors d body fluids, the athletes were instructed not to ingest larg at least 30 min before, and not to consume alcoholic beve exercise within 24 h other than the Taekwondo training se

Statistical Analysis
The normality and sphericity of the data were verifie Mauchly tests. If neither the normality nor the sphericity a ametric tests and the Greenhouse-Geisser correction wer both the CMJ and FSKTmult tests during the familiari through the paired student t-test [21]. Reliability was veri class correlation coefficient (ICC) [23]. A two-way ANOV applied for the TBM regarding the amount of calories inge ronutrients throughout the weeks. This procedure (time class correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0. p 2 = 0.01), or in the week x situation interaction (F(6) = 1.550; p = 0.182; through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0. p 2 = 0.16). Table 1 shows the respective results.  the means of jump heights in two consecutive sessions [21]. All sessions were performed using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 1000 Hz with 1 N accuracy).
The FSKTmult test was applied ten minutes after the CMJ test and encompassed three rounds of five sets with 10 s of stimuli, 10 s of interval rest between sets, and a oneminute interval between rounds [7]. The test was conducted using Boomboxe ® (Simulacare, São Paulo, Brazil), and the athletes were instructed to perform the maximum number of kicks possible. During the FSKTmult test, all athletes used a heart rate sensor (Polar H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have both the mean (HRmed) and maximum (HRmax) heart rates measured, and at the end of the test, they answered the RPE immediately. The performance analysis involved registering the total number of kicks (TNK) and the mean of kicks performed (MK) during three rounds. Additionally, the kick decrease index (KDI) was calculated using the following equation proposed by Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes in FED (Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with a oneminute interval rest between them. Ten minutes later, the FSKTmult test was performed following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last training session, whereas the tests in FAST took place on Saturdays after the 14 h rest interval from the Friday training session (Figure 1). For the tests in FAST, the athletes were instructed to have their last meal of the day 12 h before. The same test sessions and procedures as the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a digital scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To prevent potential small, systematic, and predictable errors due to changes in the balance of body fluids, the athletes were instructed not to ingest large amounts of water, to urinate at least 30 min before, and not to consume alcoholic beverages or perform any physical exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk and Mauchly tests. If neither the normality nor the sphericity assumptions were met, non-parametric tests and the Greenhouse-Geisser correction were applied. The stabilization of both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0. the means of jump heights in two consecutive ses using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, P The FSKTmult test was applied ten minute three rounds of five sets with 10 s of stimuli, 10 s o minute interval between rounds [7]. The test wa lacare, São Paulo, Brazil), and the athletes were ins ber of kicks possible. During the FSKTmult test, al H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil maximum (HRmax) heart rates measured, and at RPE immediately. The performance analysis inv kicks (TNK) and the mean of kicks performed (M the kick decrease index (KDI) was calculated usin Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reli ( Figure 1). The CMJ height in BL was assessed by minute interval rest between them. Ten minutes l following the same familiarization procedures.
The test sessions in FED were conducted on session, whereas the tests in FAST took place on Sa the Friday training session (Figure 1). For the test to have their last meal of the day 12 h before. Th the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-interve scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on vent potential small, systematic, and predictable body fluids, the athletes were instructed not to in at least 30 min before, and not to consume alcoho exercise within 24 h other than the Taekwondo tra 2. 6

. Statistical Analysis
The normality and sphericity of the data we Mauchly tests. If neither the normality nor the sph ametric tests and the Greenhouse-Geisser correc both the CMJ and FSKTmult tests during the through the paired student t-test [21]. Reliability w class correlation coefficient (ICC) [23]. A two-way applied for the TBM regarding the amount of calor ronutrients throughout the weeks. This procedure the performance variables (CMJ, TNK, MK, HRm [LAC] in different situations were analyzed throu measures (week x situation x moment). Bonferro where differences occurred. The Cohen's d effec based on the partial ETA (ŋp 2 ) square. The effect large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25 [24,25]. All data are presented as mean, standard (CI95%). All analyses considered a significance le were performed on SPSS version 20.0. the means of jump heights in two consecutive sessions [21]. A using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 1000 The FSKTmult test was applied ten minutes after the C three rounds of five sets with 10 s of stimuli, 10 s of interval re minute interval between rounds [7]. The test was conducted lacare, São Paulo, Brazil), and the athletes were instructed to p ber of kicks possible. During the FSKTmult test, all athletes us H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have bo maximum (HRmax) heart rates measured, and at the end of RPE immediately. The performance analysis involved regis kicks (TNK) and the mean of kicks performed (MK) during t the kick decrease index (KDI) was calculated using the follow Santos and Franchini [22].
best FSKT × number of sets

Performance Protocols
The BL was performed 48 h after the last reliability sessi (Figure 1). The CMJ height in BL was assessed by applying a s minute interval rest between them. Ten minutes later, the FSK following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, session, whereas the tests in FAST took place on Saturdays afte the Friday training session (Figure 1). For the tests in FAST, t to have their last meal of the day 12 h before. The same test the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays a vent potential small, systematic, and predictable errors due t body fluids, the athletes were instructed not to ingest large am at least 30 min before, and not to consume alcoholic beverag exercise within 24 h other than the Taekwondo training sessio 2. 6

. Statistical Analysis
The normality and sphericity of the data were verified u Mauchly tests. If neither the normality nor the sphericity assum ametric tests and the Greenhouse-Geisser correction were a both the CMJ and FSKTmult tests during the familiarizati through the paired student t-test [21]. Reliability was verified class correlation coefficient (ICC) [23]. A two-way ANOVA w applied for the TBM regarding the amount of calories ingested ronutrients throughout the weeks. This procedure (time x situ the performance variables (CMJ, TNK, MK, HRmed, HRmax [LAC] in different situations were analyzed through a three-w measures (week x situation x moment). Bonferroni's post ho where differences occurred. The Cohen's d effect size for pa based on the partial ETA (ŋp 2 ) square. The effect size was con large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0. [24,25]. All data are presented as mean, standard deviation, a (CI95%). All analyses considered a significance level of α = 0 were performed on SPSS version 20.0. p 2 = 0.13). The Friedman test also did not show a difference in the HRmax between situations (p = 0.478). These results are shown in Table 2  the means of jump heights in two consecutive sessions [21]. All sessions were performed using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 1000 Hz with 1 N accuracy).
The FSKTmult test was applied ten minutes after the CMJ test and encompassed three rounds of five sets with 10 s of stimuli, 10 s of interval rest between sets, and a oneminute interval between rounds [7]. The test was conducted using Boomboxe ® (Simulacare, São Paulo, Brazil), and the athletes were instructed to perform the maximum number of kicks possible. During the FSKTmult test, all athletes used a heart rate sensor (Polar H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have both the mean (HRmed) and maximum (HRmax) heart rates measured, and at the end of the test, they answered the RPE immediately. The performance analysis involved registering the total number of kicks (TNK) and the mean of kicks performed (MK) during three rounds. Additionally, the kick decrease index (KDI) was calculated using the following equation proposed by Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes in FED (Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with a oneminute interval rest between them. Ten minutes later, the FSKTmult test was performed following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last training session, whereas the tests in FAST took place on Saturdays after the 14 h rest interval from the Friday training session (Figure 1). For the tests in FAST, the athletes were instructed to have their last meal of the day 12 h before. The same test sessions and procedures as the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a digital scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To prevent potential small, systematic, and predictable errors due to changes in the balance of body fluids, the athletes were instructed not to ingest large amounts of water, to urinate at least 30 min before, and not to consume alcoholic beverages or perform any physical exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk and Mauchly tests. If neither the normality nor the sphericity assumptions were met, non-parametric tests and the Greenhouse-Geisser correction were applied. The stabilization of both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intraclass correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of macronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0. p 2 = 0.28; Nutrients 2023, 15, x FOR PEER REVIEW the means of jump heights in two consecutive sessions [21]. All sessions were perf using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 1000 Hz with 1 N accurac The FSKTmult test was applied ten minutes after the CMJ test and encom three rounds of five sets with 10 s of stimuli, 10 s of interval rest between sets, and minute interval between rounds [7]. The test was conducted using Boomboxe ® lacare, São Paulo, Brazil), and the athletes were instructed to perform the maximum ber of kicks possible. During the FSKTmult test, all athletes used a heart rate sensor H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have both the mean (HRme maximum (HRmax) heart rates measured, and at the end of the test, they answe RPE immediately. The performance analysis involved registering the total num kicks (TNK) and the mean of kicks performed (MK) during three rounds. Additi the kick decrease index (KDI) was calculated using the following equation propo Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with the athletes (Figure 1). The CMJ height in BL was assessed by applying a set of five jumps with minute interval rest between them. Ten minutes later, the FSKTmult test was perf following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the last tr session, whereas the tests in FAST took place on Saturdays after the 14 h rest interv the Friday training session (Figure 1). For the tests in FAST, the athletes were ins to have their last meal of the day 12 h before. The same test sessions and proced the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. T vent potential small, systematic, and predictable errors due to changes in the bala body fluids, the athletes were instructed not to ingest large amounts of water, to u at least 30 min before, and not to consume alcoholic beverages or perform any p exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-W Mauchly tests. If neither the normality nor the sphericity assumptions were met, no ametric tests and the Greenhouse-Geisser correction were applied. The stabiliza both the CMJ and FSKTmult tests during the familiarization sessions was an through the paired student t-test [21]. Reliability was verified by a two-way mixed class correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measur applied for the TBM regarding the amount of calories ingested and the proportion o ronutrients throughout the weeks. This procedure (time x situation) was used to co the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI). [B [LAC] in different situations were analyzed through a three-way ANOVA with re measures (week x situation x moment). Bonferroni's post hoc test was used to id where differences occurred. The Cohen's d effect size for paired samples was v based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medi large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respe [24,25]. All data are presented as mean, standard deviation, and 95% confidence i (CI95%). All analyses considered a significance level of α = 0.05. All statistical an were performed on SPSS version 20.0. the means of jump heights in two consecutive sessions [21]. All session using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 1000 Hz with 1 The FSKTmult test was applied ten minutes after the CMJ test three rounds of five sets with 10 s of stimuli, 10 s of interval rest betwee minute interval between rounds [7]. The test was conducted using B lacare, São Paulo, Brazil), and the athletes were instructed to perform th ber of kicks possible. During the FSKTmult test, all athletes used a heart H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have both the m maximum (HRmax) heart rates measured, and at the end of the test, t RPE immediately. The performance analysis involved registering the kicks (TNK) and the mean of kicks performed (MK) during three roun the kick decrease index (KDI) was calculated using the following equa Santos and Franchini [22].

Performance Protocols
The BL was performed 48 h after the last reliability session with th ( Figure 1). The CMJ height in BL was assessed by applying a set of five minute interval rest between them. Ten minutes later, the FSKTmult te following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h afte session, whereas the tests in FAST took place on Saturdays after the 14 h the Friday training session (Figure 1). For the tests in FAST, the athlete to have their last meal of the day 12 h before. The same test sessions a the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then week scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before vent potential small, systematic, and predictable errors due to changes body fluids, the athletes were instructed not to ingest large amounts o at least 30 min before, and not to consume alcoholic beverages or perf exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Mauchly tests. If neither the normality nor the sphericity assumptions w ametric tests and the Greenhouse-Geisser correction were applied. T both the CMJ and FSKTmult tests during the familiarization sessio through the paired student t-test [21]. Reliability was verified by a two class correlation coefficient (ICC) [23]. A two-way ANOVA with repea applied for the TBM regarding the amount of calories ingested and the p ronutrients throughout the weeks. This procedure (time x situation) wa the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, an [LAC] in different situations were analyzed through a three-way ANO measures (week x situation x moment). Bonferroni's post hoc test wa where differences occurred. The Cohen's d effect size for paired sam based on the partial ETA (ŋp 2 ) square. The effect size was considered s large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = [24,25]. All data are presented as mean, standard deviation, and 95% c (CI95%). All analyses considered a significance level of α = 0.05. All s were performed on SPSS version 20.0. the means of jump heights in two consecutive sessions [21]. using PLA3-1D-7KN/JBA Zb (Staniak; Warsaw, Poland, 100 The FSKTmult test was applied ten minutes after the three rounds of five sets with 10 s of stimuli, 10 s of interval minute interval between rounds [7]. The test was conduct lacare, São Paulo, Brazil), and the athletes were instructed to ber of kicks possible. During the FSKTmult test, all athletes u H10, Polar Electro Brasil, Ltda., Sao Paulo, Brazil) to have maximum (HRmax) heart rates measured, and at the end o RPE immediately. The performance analysis involved reg kicks (TNK) and the mean of kicks performed (MK) during the kick decrease index (KDI) was calculated using the foll Santos and Franchini [22].
best FSKT × number of sets

Performance Protocols
The BL was performed 48 h after the last reliability ses (Figure 1). The CMJ height in BL was assessed by applying a minute interval rest between them. Ten minutes later, the F following the same familiarization procedures.
The test sessions in FED were conducted on Monday session, whereas the tests in FAST took place on Saturdays a the Friday training session (Figure 1). For the tests in FAST to have their last meal of the day 12 h before. The same tes the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays vent potential small, systematic, and predictable errors due body fluids, the athletes were instructed not to ingest large at least 30 min before, and not to consume alcoholic bevera exercise within 24 h other than the Taekwondo training sess 2. 6

. Statistical Analysis
The normality and sphericity of the data were verified Mauchly tests. If neither the normality nor the sphericity ass ametric tests and the Greenhouse-Geisser correction were both the CMJ and FSKTmult tests during the familiariza through the paired student t-test [21]. Reliability was verifie class correlation coefficient (ICC) [23]. A two-way ANOVA applied for the TBM regarding the amount of calories ingeste ronutrients throughout the weeks. This procedure (time x si the performance variables (CMJ, TNK, MK, HRmed, HRm [LAC] in different situations were analyzed through a three measures (week x situation x moment). Bonferroni's post h where differences occurred. The Cohen's d effect size for based on the partial ETA (ŋp 2 ) square. The effect size was c large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = [24,25]. All data are presented as mean, standard deviation, (CI95%). All analyses considered a significance level of α = were performed on SPSS version 20.0. p 2 = 0.65, respectively) ( Table 3). The BonFerroni posthoc test indicated that these differences occurred between the third and fourth weeks (p = 0.021; 95%CI = −8.38. −0.68). The test also indicated that the values  Table 2 shows the respective results.

Statistical Analysis
The normality and sphericity of the data Mauchly tests. If neither the normality nor the ametric tests and the Greenhouse-Geisser co both the CMJ and FSKTmult tests during through the paired student t-test [21]. Reliabi class correlation coefficient (ICC) [23]. A twoapplied for the TBM regarding the amount of c ronutrients throughout the weeks. This proced the performance variables (CMJ, TNK, MK, H [LAC] in different situations were analyzed th measures (week x situation x moment). Bonf where differences occurred. The Cohen's d e based on the partial ETA (ŋp 2 ) square. The ef large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = [24,25]. All data are presented as mean, stand (CI95%). All analyses considered a significan were performed on SPSS version 20.0.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly using a digital scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tests. To pre-vent potential small, systematic, and predictable errors due to changes in the balance of body fluids, the athletes were instructed not to ingest large amounts of water, to urinate at least 30 min before, and not to consume alcoholic beverages or perform any physical exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro-Wilk and Mauchly tests. If neither the normality nor the sphericity assumptions were met, non-par-ametric tests and the Greenhouse-Geisser correction were applied. The stabilization of both the CMJ and FSKTmult tests during the familiarization sessions was analyzed through the paired student t-test [21]. Reliability was verified by a two-way mixed intra-class correlation coefficient (ICC) [23]. A two-way ANOVA with repeated measures was applied for the TBM regarding the amount of calories ingested and the proportion of mac-ronutrients throughout the weeks. This procedure (time x situation) was used to compare the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI).
[BG] and [LAC] in different situations were analyzed through a three-way ANOVA with repeated measures (week x situation x moment). Bonferroni's post hoc test was used to identify where differences occurred. The Cohen's d effect size for paired samples was verified based on the partial ETA (ŋp 2 ) square. The effect size was considered small, medium, or large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, respectively [24,25]. All data are presented as mean, standard deviation, and 95% confidence interval (CI95%). All analyses considered a significance level of α = 0.05. All statistical analyses were performed on SPSS version 20.0.

Performance Protocols
The BL was performed 48 h after the last reliability session with the athle (Figure 1). The CMJ height in BL was assessed by applying a set of five jumps w minute interval rest between them. Ten minutes later, the FSKTmult test was following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h after the la session, whereas the tests in FAST took place on Saturdays after the 14 h rest int the Friday training session (Figure 1). For the tests in FAST, the athletes were to have their last meal of the day 12 h before. The same test sessions and pro the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then weekly usin scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and before the tes vent potential small, systematic, and predictable errors due to changes in the body fluids, the athletes were instructed not to ingest large amounts of water, at least 30 min before, and not to consume alcoholic beverages or perform an exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using the Shapiro Mauchly tests. If neither the normality nor the sphericity assumptions were me ametric tests and the Greenhouse-Geisser correction were applied. The stabi both the CMJ and FSKTmult tests during the familiarization sessions was through the paired student t-test [21]. Reliability was verified by a two-way m class correlation coefficient (ICC) [23]. A two-way ANOVA with repeated mea applied for the TBM regarding the amount of calories ingested and the proporti ronutrients throughout the weeks. This procedure (time x situation) was used t the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE, and KDI) [LAC] in different situations were analyzed through a three-way ANOVA wit measures (week x situation x moment). Bonferroni's post hoc test was used where differences occurred. The Cohen's d effect size for paired samples w based on the partial ETA (ŋp 2 ) square. The effect size was considered small, m large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋp 2 = 0.64, re [24,25]. All data are presented as mean, standard deviation, and 95% confiden (CI95%). All analyses considered a significance level of α = 0.05. All statistica were performed on SPSS version 20.0.

Performance Protocols
The BL was performed 48 h after the last reliability session wi ( Figure 1). The CMJ height in BL was assessed by applying a set of f minute interval rest between them. Ten minutes later, the FSKTmu following the same familiarization procedures.
The test sessions in FED were conducted on Mondays, 48 h session, whereas the tests in FAST took place on Saturdays after the the Friday training session (Figure 1). For the tests in FAST, the ath to have their last meal of the day 12 h before. The same test sessio the BL were applied.

Total Body Mass Measures
The TBM was measured in FAST (pre-intervention) and then w scale (Welmy ® , Santa Bárbara d'Oeste, Brazil) on Saturdays and be vent potential small, systematic, and predictable errors due to chan body fluids, the athletes were instructed not to ingest large amoun at least 30 min before, and not to consume alcoholic beverages or exercise within 24 h other than the Taekwondo training session.

Statistical Analysis
The normality and sphericity of the data were verified using t Mauchly tests. If neither the normality nor the sphericity assumptio ametric tests and the Greenhouse-Geisser correction were applied both the CMJ and FSKTmult tests during the familiarization se through the paired student t-test [21]. Reliability was verified by a class correlation coefficient (ICC) [23]. A two-way ANOVA with re applied for the TBM regarding the amount of calories ingested and t ronutrients throughout the weeks. This procedure (time x situation) the performance variables (CMJ, TNK, MK, HRmed, HRmax, RPE [LAC] in different situations were analyzed through a three-way A measures (week x situation x moment). Bonferroni's post hoc test where differences occurred. The Cohen's d effect size for paired based on the partial ETA (ŋp 2 ) square. The effect size was consider large if d = 0.20 or ŋp 2 = 0.04, d = 0.50 or ŋp 2 = 0.25, and d = 0.8 or ŋ [24,25]. All data are presented as mean, standard deviation, and 95 (CI95%). All analyses considered a significance level of α = 0.05. A were performed on SPSS version 20.0.

Energy Intake
The total calories ingested in the first week were lower than the BL, whereas in the second week, they were greater than in the first week. The total values of calories ingested in the third and fourth weeks were similar but increased compared with the second week. Despite these variations, the total number of calories ingested during IF was lower than the BL. However, no difference between the BL and the intervention weeks was found. In addition, the relative ingested amounts of Kcal/kg, carbohydrate (CHOg/kg), lipid (LIPg/kg), and protein (PROg/kg) also showed no difference (Table 3).

Discussion
This study aimed to investigate the effect of IF on TBM and performance in Taekwondo. The hypothesis was that the 12 h fasting protocol with breakfast omission would reduce the TBM without decreasing performance. Throughout the four weeks of IF, the results showed a decrease in TBM in the first two weeks, which then remained unchanged in the subsequent weeks. The physical performance was maintained during IF and kept unchanged after the application of the tests, either in a fasted or fed state. Therefore, the study hypothesis was partially proven.
Corroborating these findings, Silva et al. [7] observed that a 12 h acute fast with breakfast omission reduces the TBM of Taekwondo athletes without affecting the CMJ and FSKT tests performance. In our study, the lower TBM in the first two weeks corroborates the efficiency of fasting in a short-term intervention, with limited weight reduction. The athletes might not maintain the IF any longer without a negative energy balance to reduce Nutrients 2023, 15, 3131 9 of 12 TBM. Our results show that the mean energy intake decreases initially but increases in the final weeks; however, such a difference is not statistically significant.
Studies with karate athletes performing IF showed a non-significant difference with a small effect size reduction in TBM before (62.4 ± 7.4 kg) and after (61.9 ± 7.1 kg) the Ramadan fast [14]. Corroborating with these results, Zarrouk et al. [10] also found no difference in TBM between pre-(62.1 ± 7.4 kg) and post-(61.8 ± 7.1 kg) evaluation. The authors attribute these results to changes in the diet composition, with an increase in energy and daily water intake. However, herein, we did not observe such a change in the eating behavior of the athletes. Such diverging results might be partially associated with the fasting protocol adopted and Ramadan. In our study, fasting covered the periods of overnight and sleep, when the individuals are less physically active. Therefore, fasting might not have a sufficient impact on energy reserves and hormonal modulation, neither altering the metabolism nor changing eating behavior, as would be expected for IF [9,12,26].
Therefore, the lower TBM during fasting is acute if not associated with a negative energy balance [8,10,14,15]. However, the same sample size with different morphological profiles can have different results. Therefore, a lower TBM with a small effect size in combat sports involving eutrophic athletes might be as important as a large effect size in sedentary obese individuals.
The change in TBM in the first weeks of intervention, without differences either in energy intake or diet composition, may have resulted from the smaller amount of food ingested in the hours before the weight measure, which was performed during the fasting period. Consequently, there is an acute reduction in TBM due to the limited presence of food fragments, nutritional molecules, and water associated with solutes in the gastrointestinal tract during the digestive process [27]. Acute dehydration promoted by fasting might also contribute to the acute reduction in TBM [27]. In addition, the muscle glycogen stores might recover less with a lower water content in the cells [27]. However, such a lower concentration of muscle glycogen may not be sufficient to negatively influence physical performance, considering the low demand for this substrate during the tests performed.
Furthermore, there is an average 28% compensatory response in non-active energy expenditure due to the lower basal energy expenditure, suggesting that only 72% of the extra calories burned in additional activities are extra calories burned that day [28]. Such a compensation in energy expenditure might result from the lower mitochondrial activity [11], which would justify the reduction in TBM in the first weeks, which some athletes then maintained and/or recovered in the last weeks. It is worth noting that our experiment did not cover the measures of glycogen stores, basal energy expenditure, or mitochondrial activity, thus representing a limitation for the interpretation and discussion of the results.
Herein, neither the CMJ nor the FSKT decreased with the application of the IF protocol, either in the FED or FAST states. These results contradict other studies with judokas and karatekas that found significantly lower performance after the tests were applied in the late afternoon during Ramadan [13,15,16]. Those results might be associated with changes in the circadian rhythm due to fasting or the particularity of Ramadan fasting, which may enlarge muscle and liver glycogen stores in the morning rather than in the afternoon [29,30]. Thus, the effect of fasting on physical performance can be influenced by the time of day determined for fasting and the application of the tests. However, other studies applied nonspecific tests to Taekwondo and Karate athletes subjected to Ramadan fasting and found no changes in performance, even when conducting the tests in the afternoon [10,14,17]. In contrast, a specific taekwondo test performed at the end of the day indicated a lower TNK during Ramadan fasting [18]. Such diverging results might indicate that not only the time of day can influence the outcomes but also the type of test used, the metabolic demand, and the physical capacity evaluated. Thus, further and more specific studies on this topic should be carried out.
The lower [BG] in the pre-test measure for the FAST state indicates that the volunteers might not have had a meal before the tests. No statistical difference was found in the post-test [BG] between the situations. There was a tendency toward a greater increase in the [BG] for the FAST state compared with the FED. Such a result indicates a potentially greater mobilization of liver glycogen during the test in the FAST state [31]. In addition, the post-test in the FED state also showed higher [LAC] values compared with the FAST, indicating that the lactic anaerobic pathway was demanded and responded in different proportions under different exercise intensities. These data can also indicate less oxidation of substrates for the test applied in the FAST state [31].
Furthermore, the CMJ test, which has a low demand for anaerobic lactic metabolism, might not be sensitive enough to detect performance changes resulting from fasting in Taekwondo athletes [7,17]. Likewise, other studies have demonstrated that either for acute fasting [7] or FED [32], the mean and total of kicks performed in the FSKT did not change. Therefore, even with lower [BG], muscle, and liver glycogen reserves in the pre-test through the fasting protocol, it would also be insufficient to affect performance in a specific modality task. However, the three rounds of the FSKT may have had a greater contribution from aerobic metabolism, as shown in simulated fights [33]. However, this is possibly the only study with a specific test for Taekwondo after a 12 h fast demonstrating a lower performance in the TNK during IF [18]. Contrary to our study, in the aforementioned studies [18,33], the tests were applied in the afternoon. Therefore, there is a lower chance of confirming the hypothesis that a 12 h night IF with the test applied in the morning reduces glycogen stores. Such a scenario can have a lower impact on performance, which seems more plausible than the hypothesis that performance can be affected by the greater aerobic contribution throughout the three rounds of the FSKT test.
Both the HRmed and HRmax for the three FSKT rounds have very high values, as reported in the literature for training sessions, simulated fights, and official competitions [33]. Thus, this indicates that the adaptation in the FSKT test applied in our study reproduced the physiological demand of the modality. In addition, the mean RPE reported after each test round was also maximum or very close to the maximum, indicating that the volunteers performed maximal effort. The KDI did not differ according to the different situations either. No difference in the KDI has also been indicated in studies using the FSKT to rank the level of physical conditioning, competitive level, and/or analyze the effect of different training protocols on performance [22,33]. Therefore, analyzing the KDI may be insufficient to infer either an improvement or worsening in the performance of athletes. Furthermore, all the obtained results should be treated with caution due to the sample size and the variability of ages among the participants in this study.
Further studies should perform the three FSKT rounds using an ergo spirometer to measure the contribution of each energy system and substrate, applied at different times of the day, in both the FAST and FED states. Additionally, it is recommended to incorporate tools and technologies for measuring muscular and hepatic glycogen stores to investigate the effect of intermittent fasting on athletic performance. Furthermore, the effect of intermittent fasting in real and simulated combat situations should be evaluated in future research.
Aware of all the limitations reported throughout the text, the results of the present study can support athletes, coaches, and nutritionists in their practices and prescriptions, according to the competitive calendar and individual objectives. Furthermore, in this study, we aim to advance the scientific discussion regarding intermittent fasting protocols, which are more closely aligned with the cultural reality of Western countries, as well as the evaluation of physical performance measured by non-specific and specific tests. Therefore, it seems that this intermittent fasting protocol can be an efficient strategy for weight loss in athletes over a short period of time, allowing them to fit into the appropriate category without compromising performance.

Conclusions
Intermittent fasting with 12 h time-restricted feeding and breakfast omission can promote a decrease in total body mass in the first two weeks, with stabilization in the third and fourth weeks. However, this can be promoted without decreasing Taekwondo athletes' performance. Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.
Data Availability Statement: All data used within this manuscript are available upon request.