Journal of Functional Morphology and Kinesiology

Background: Functional lumbar segmental instability (FLSI) is a clinically significant subtype of nonspecific low back pain, characterized by impaired motor control during mid-range spinal motion. Despite its prevalence, diagnostic approaches remain fragmented, and no single clinical test reliably captures its complexity. This scoping review aims to synthesize current evidence on the reliability, validity, subclassification, and predictive value of manual tests used in the evaluation of FLSI, and to identify conceptual and methodological gaps in the literature. Methods: A structured search was conducted across five databases (PubMed, Scopus, Web of Science, CINAHL, Embase) between May and August 2025. Twenty-four empirical studies and eleven foundational conceptual sources were included. Data were charted into five thematic domains: conceptual frameworks, diagnostic accuracy, reliability, subclassification models, and predictive value. Methodological appraisal was performed using QUADAS and QAREL tools. Results: The Passive Lumbar Extension Test (PLET) demonstrated the most consistent reliability and clinical utility. The Prone Instability Test (PIT) and Posterior Shear Test (PST) showed variable performance depending on protocol standardization. Subclassification models distinguishing functional, structural, and combined instability achieved high inter-rater agreement. Screening tools for sub-threshold lumbar instability (STLI) showed preliminary feasibility. Predictive validity of manual tests for rehabilitation outcomes was inconsistent, suggesting the need for multivariate models. Conclusions: Manual tests can support the clinical evaluation of FLSI when interpreted within structured diagnostic frameworks. Subclassification models and composite test batteries enhance diagnostic precision, but standardization and longitudinal validation remain necessary. Future research should prioritize protocol harmonization, integration of sensor-based technologies, and stratified outcome studies to guide individualized rehabilitation planning. Full article

Background: Identifying factors that predispose futsal athletes to anterior cruciate ligament (ACL) injuries is crucial for developing effective prevention strategies. This study aimed to determine whether specific dermatoglyphic markers are associated with an increased risk of ACL injury in this population. Methods: This retrospective case–control study analyzed 212 former male futsal athletes, divided into an injury group (n = 85 with a history of ACL injury) and a control group (n = 127 without injury). Fingerprint patterns (arches, loops, and whorls) and quantitative line counts were collected and analyzed using the dermatoglyphics method. Chi-square tests and log-linear regression were used for statistical analysis. Results: While no significant differences were found in the quantitative line counts between groups (p > 0.05), a significant association was identified for specific fingerprint patterns. The spiral whorl (WS) pattern on the left index finger (p = 0.043) and the right little finger (p = 0.007) was significantly more frequent in the ACL injury group. Overall, athletes presenting the WS pattern had approximately twice the odds of having a history of ACL injury (OR = 2.028, 95% CI 1.493–2.756). Conclusions: The findings suggest that specific dermatoglyphic patterns, particularly the spiral whorl, may serve as an indicator of a potential biological predisposition to ACL injuries in futsal athletes. This finding suggests dermatoglyphics could be a potential component for future multifactorial risk assessment models in futsal. Full article

Background: Goalkeeper actions directly influence match outcomes and overall team performance. Neuromuscular determinants (e.g., perception–action coupling, reaction speed, rate of force development (RFD), balance, etc.) translate into higher save probability, faster second actions, and more accurate distribution. Objectives: This systematic review analysed neuromuscular performance factors in 11-a-side football goalkeepers and examined how these factors evolve across age and sex groups. Methods: The review adhered to the PRISMA 2020 Statement guidelines. A systematic search was conducted using the PubMed, Web of Science, SPORTDiscus, PsycINFO, Dialnet, LILACS, and Scopus databases. Studies that assessed any aspect of goalkeepers’ neuromuscular performance except for aerobic endurance and VO₂ max (due to the short duration of goalkeeping actions) were included, regardless of the type of observational design. Results: Thirty-five studies were finally included in the synthesis, encompassing neuromuscular performance factors such as agility, speed, anaerobic power, strength, flexibility, and dynamic balance and coordination. The findings underscore the need for neuromuscular training for goalkeepers, particularly agility training. Neuromuscular performance improves with age, especially in linear speed, agility, change-of-direction speed, strength, and power; however, flexibility shows no significant progression. This review identifies key tests for evaluating goalkeepers’ neuromuscular capacities across major performance domains. Conclusions: Although sex differences are apparent, the main limitation is the lack of research on neuromuscular performance in male and female goalkeepers, making it difficult to define indicators for different age and sex categories. Full article

Background: Repeated vertical jump tests are widely used to assess neuromuscular function and lower limb performance. However, inconsistent formulas for average power output produce large discrepancies, limiting comparability across studies and limiting practical applications. This study aimed to compare three different models for the calculation of average power output, Bosco, Miron Georgescu (MG), and Modified Miron Georgescu-15s (MGM-15), applied to identical jump test data, in order to evaluate their computational behavior and practical relevance in athlete performance profiling. Methods: A single-group quasi-experimental study was conducted with 25 physically active male university students (mean age: 21.4 ± 2.7 years), who performed a 15 s repeated vertical jump test on the OptoJump Next system. Raw parameters including flight time, contact time, and jump height were recorded and exported. Average power output (W/kg) was subsequently calculated using three distinct computational models, each applied to the same dataset of flight and contact times. A repeated-measures ANOVA was used to compare outputs across models, with Bonferroni-adjusted pairwise comparisons for post hoc analysis (α = 0.05). Results: Significant differences were observed (p < 0.001). The Bosco model produced the highest values of average power (40.13 ± 8.56 W/kg), followed by MG (21.07 ± 5.92 W/kg), while MGM-15 yielded the lowest and most consistent outputs (4.08 ± 0.61 W/kg). Effect sizes were very large (η²_p = 0.952), confirming that calculation models strongly influenced the outcomes. Conclusions: The findings demonstrate that average power output differed markedly across formulas, despite identical performance data. Bosco and MG models tended to overestimate values due to simplified assumptions, whereas the MGM-15 method produced lower and more consistent outputs that may better capture repeated jump demands. The standardization of computational models is fundamental to ensure comparability and to improve athlete performance profiling in research and practice. Full article

Background: The off-season is often characterized by a significant decrease or even a complete cessation of training. If this reduction is not planned properly, it can result in detraining. Despite numerous studies examining the effects of HIIT in football players, its specific role in mitigating detraining and maintaining aerobic and anaerobic performance during the off-season in adolescent female football players remains underexplored. Therefore, this study evaluated the effects of a 4-week off-season high-intensity training (HIIT) program on aerobic performance level and sprint endurance ability in Under-15 (U-15) female football players. Methods: Fifteen U-15 female football players from a professional club completed an experimental protocol consisting of two HIIT formats: Small-Sided Games (SSGs) and Repeated Sprint Training (RST), each performed twice weekly. Before and after the intervention period, participants performed the Yo-Yo Intermittent Recovery Level 1 (YYIR1) test to gauge aerobic performance and the 30-seconds sprint test to assess sprint endurance. The internal training load was monitored via heart rate (HR) and blood lactate concentration ([La]⁺), while external training load metrics included the total distance (TD), moderate-speed distance (MSD), high-speed distance (HSD), acceleration distance (≥3 m·s⁻²; ACC), and deceleration distance (≤−3 m·s⁻²; DEC). Results: YYIR1 improved by 57% (p = 0.0001; d = 1.12; 95% CI: 121.94–224.71) and the 30-s test performance increased by 13% (p = 0.004; d = 0.91; and 95% CI: 14.46–25.53) following the intervention period. A very large correlation between time spent at 90–95% HRmax and the 30-s test (r = 0.90, p = 0.0001) and YYIR1 (r = 0.81, p = 0.0001) performance was observed. Very large and nearly perfect correlations between DHS and YYIR1 (r = 0.82, p = 0.0001) and the 30-s test performance (r = 0.94, p = 0.0001), respectively, were found. Conclusions: In U-15 female football players, a four-week off-season HIIT program improved both aerobic performance and sprint endurance ability, indicating that a HIIT regime attenuates the off-season detraining, thus supporting a better-conditioned return to play. Coaches may implement 4-week high-intensity off-season programs to enhance aerobic performance and start the pre-season with a satisfactory level of aerobic fitness and sprint endurance. Full article

Objectives: Plyometric training is a well-established method for enhancing jump performance in basketball and volleyball athletes but has certain limitations. Kettlebell training may provide a viable alternative as it mimics key biomechanical aspects of jumping, like explosive hip and knee extension during a ballistic hip–hinge pattern. Because evidence remains limited, this study aimed to compare the effects of both training methods. Methods: Thirty-eight volleyball and basketball club athletes (age: 22 (4.3); male = 29, female = 9) completed this study. Countermovement jump (CMJ), squat jump (SJ), drop jump (DJ), body fat percentage (FM), and muscle mass percentage (MM) were assessed pre- and post-intervention. The participants were assigned to one of three groups: a kettlebell training group (KbG), a plyometric training group (PG), or a control group (CG). Both the KbG and PG completed two supervised 25-min training sessions per week for six weeks, while the CG did not engage in any additional training intervention. The level of significance was set at p ≤ 0.05. Results: There were no significant differences in CMJ, SJ, and DJ performance between the groups before the intervention. Significant differences in change between the groups from pre- to post-test were found for the SJ (p = 0.006), but not for the DJ (p = 0.06), CMJ (p = 0.26), FM (p = 0.9), and MM (p = 0.55). Pairwise comparisons revealed significantly greater positive change in the KbG than in the CG for the SJ (p = 0.003) and DJ (p = 0.03). Within-group analyses showed significant improvements in the KbG for the CMJ (p = 0.04), SJ (p < 0.001), and DJ (p = 0.003) performance, whereas FM and MM did not change. Within the PG and CG, no significant change occurred. Conclusions: Kettlebell training effectively improved jump performance and may therefore serve as a valuable component within strength and conditioning programs for basketball and volleyball athletes. Full article

Objectives: SailGP is an international professional mixed-sex sailing competition, which uses F50 foiling catamarans capable of reaching speeds up to ~100 km/h. This seminal study assesses injuries and illnesses observed by male and female sailors during trainings and competitions in SailGP’s third season. This study aims to assess injury and illness incidence, comparing results with other professional sailing events and high-performance sports. In addition, injury and illness risk factors (sex and position) will be explored with the goal to reduce morbidity for future seasons. Materials and Methods: This retrospective cohort design analysed medical records of male and female sailors during SailGP’s third season (April 2022 to May 2023). Risk factors assessed included sailor sex, sailor position (helm, strategist, grinder, flight controller and wing trimmer), sailing venue, wind speed and mechanism of injury/nature of illness. International Olympic Committee reporting guidelines on injuries and illnesses were followed, including the STROBE-SIIS checklist. Confidence intervals were set at 95%, statistical tests were two-sided and p-values < 0.05 were considered statistically significant. Results: A total of 40 on-water injuries were reported in 32 athletes. Injury incidence was greater during competitions than trainings, with strategists and then grinders being the most frequently injured positions. Competition injury incidence was 32.6 per 1000 h and 6.42 injuries per 365 days. Training injury incidence was 2.62 injuries per 1000 h and 3.82 injuries per 365 days. Knee, ankle, hand and head injuries were most prevalent, with three concussions observed during trainings and competitions (two female and one male). Direct impacts and falls during manoeuvres caused most injuries. Overall injury incidence (IRR = 2.69 [95% CI 1.41–5.16]), risk of training injuries (RR = 3.75 [95% CI 1.59–8.83], p = 0.001), risk of competition injuries (RR = 1.79 [95% CI 0.65–4.90], p = 0.25) and overall concussion risk (RR = 10.04 [95% CI 0.91–110.46], p = 0.02) were greater in females. Ten sailors accounted for 17 illnesses. Females had a 3.33 increase in training and competition illnesses (IRR = 3.33 [95% CI 0.94–11.81]). Conclusions: Competition injury incidence was higher than previous reported sailing studies. Knee injuries were most prevalent and direct impacts caused most injuries. Female sailors reported a higher injury and illness incidence. These results may guide injury prevention efforts and the development of an IOC-equivalent consensus statement. Future studies should examine time loss. Full article

Background: A thorough post-myocardial infarction (MI) evaluation is essential for prognosis and rehabilitation. While cardiopulmonary exercise testing (CPET) is the standard for assessing functional capacity, combining it with dynamic stress echocardiography (DSE) may offer a more comprehensive assessment. Aim: This study examined the role of stress echocardiography (SE) in male post-MI patients by evaluating left ventricular function with conventional indices and the change in global longitudinal strain (ΔGLS) at rest and during maximal treadmill CPET. A secondary aim was to determine whether ΔGLS could provide additional value to traditional measures in post-MI care. Methods: Eighteen men with a recent MI [15 ST-elevation MI, three non-ST-elevation MI; mean age 53.2 ± 5.9 years, mean body mass index (BMI) 27.9 ± 2.2, 44.4% with a smoking history) and 18 age-matched male controls (mean age 50.1 ± 10.8 years, mean BMI 26.5 ± 2.4, 39.0% with smoking history) were enrolled. All MI patients were under optimal medical therapy, including β-blockers, which were withheld on the test day. Most underwent percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG) n = 2, or PCI for non-ST-elevation MI (NSTEMI) n = 3. Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) were measured at rest and at peak effort and correlated with CPET parameters. Results: Post-MI patients had lower LVEF (50.6% vs. 60.7% at rest; 55.3% vs. 67.4% at peak, both p < 0.001), impaired GLS (–14.7% vs. –20.2% at rest, p = 0.003; –15.8% vs. –22.7% at peak, p = 0.001), and reduced VO₂peak (29.2 vs. 41.9 mL/kg/min, p < 0.001) compared with controls. In the MI group, ΔGLS correlated with VO₂peak (r = –0.645, p = 0.003) and VE/VCO₂ (r = 0.539, p = 0.020), indicating its potential as a marker of functional reserve. Conclusions: Combined CPET and SE offered comprehensive insights into functional and myocardial performance, identifying ΔGLS as a useful non-invasive index for risk stratification and rehabilitation after MI, with high feasibility and safety. Full article

Background: Musculoskeletal disorders are disorders that affect bones, muscles, and joints, significantly impacting quality of life and academic performance. Medical students are particularly susceptible to these conditions due to academic overload, inadequate posture, and overuse of digital devices. Objectives: This study aimed at investigating the prevalence of musculoskeletal disorders and associated factors among medical students at a university centre in northwestern São Paulo State. Materials and Methods: This cross-sectional, descriptive, and analytical study involved administering a structured questionnaire and conducting clinical tests (Phalen and Finkelstein) to assess musculoskeletal disorders in 164 students. Data were analyzed using the chi-square test with a significance level of 5% (p-value < 0.05). Results: The results indicate a high incidence of musculoskeletal disorders primarily affecting the upper back, neck and shoulders. In addition, prolonged use of mobile phones and tablets and predominantly typing with the thumbs were found to be associated with an increased risk of De Quervain’s tenosynovitis. A high rate of self-medication was also observed among students, with few participants seeking medical care. These findings highlight the importance of implementing preventive strategies early in the undergraduate curriculum, emphasizing ergonomics and musculoskeletal health awareness. Conclusions: This proactive approach can significantly minimize the negative impact on students’ well-being throughout their training and subsequent professional careers. Further studies might explore ergonomic interventions and educational programmes to reduce the incidence of these disorders. Full article

Background: Combined cognitive and physical training develops resilience to mental fatigue, reduces perceived effort, and improves endurance exercise performance when compared to physical training and no training. The isolated contribution of cognitive training toward endurance performance has yet to be determined. Accordingly, we examined the effects of separate cognitive training on endurance exercise performance. Method: Two studies employed a pre-test/training/post-test design, with participants randomly assigned to cognitive training or control groups. At pre-test and post-test, participants completed a rhythmic handgrip task (Study 1) or a graded exercise test on a cycle ergometer (Study 2). In Study 1, the cognitive training group completed 20 sessions (four 20 min sessions per week for five weeks) of cognitive training (incongruent Stroop and 2-back tasks), whereas the control group completed no training. In Study 2, the cognitive training group completed nine sessions (three 10 min sessions per week for three weeks) of cognitive training (incongruent Stroop, stop-signal and typing inhibition tasks), whereas the control group completed nine sessions of sham training (congruent Stroop, sham stop-signal and sham typing inhibition tasks). Endurance exercise performance was measured as force production (Study 1) and time to exhaustion (Study 2). Heart rate, exertion and fatigue were also measured. Results: Endurance performance, indexed by force production (Study 1) and time to exhaustion (Study 2), did not change from pre-test to post-test and did not differ between cognitive training and control groups. Similarly, ratings of perceived exertion and heart rate during the exercise tasks did not differ between cognitive training and control groups (Studies 1 and 2). Conclusions: Since separate cognitive training did not improve exercise endurance performance, combined training should be used to create a synergistic training stimulus for brain adaptation and performance enhancement. Full article

Background: Muscle strength asymmetries between limbs are common in physically active populations and may influence performance and injury risk. This study aimed to: (i) analyze the reliability of the seated unilateral cable row exercise using a functional electromechanical dynamometer (FEMD) and to examine differences in reliability between sides and contraction types; (ii) investigate the relationship between the dominant and non-dominant sides, as well as between the dynamic and static force production of the back muscles; and (iii) quantify force output and assess interlimb asymmetries. Methods: Twenty-nine young physically active athletes completed two sets of four repetitions of a seated unilateral cable row at 0.30 m·s⁻¹ using the FEMD, followed by a 6-s isometric contraction. Two testing sessions were conducted seven days apart. Reliability was assessed using paired t-tests, the effect size, the coefficient of variation (CV), the standard error of measurement, and the intraclass correlation coefficient (ICC), with 95% confidence intervals. Results: Peak and average force values showed very high to extremely high relative reliability (ICC = 0.86–0.96) and acceptable absolute reliability (CV ≈ 10%). Differences between dominant and non-dominant sides varied depending on contraction type. While group-level asymmetries did not exceed 10%, individual analysis revealed that 14%, 32%, and 7% of participants had asymmetries greater than 15% in isometric, concentric, and eccentric force, respectively. Conclusions: This test demonstrates strong reliability and provides a practical method for assessing upper limb asymmetries in physically active individuals, with potential applications in performance monitoring and injury prevention. Full article

Introduction: Neck-preserving total hip arthroplasty (THA) has gained interest for conserving bone stock, restoring biomechanics, and facilitating revision surgery. The Nanos^® femoral stem, designed for metaphyseal fixation while preserving the femoral neck, represents a reliable alternative to conventional THA. This study reports 15-year clinical and radiographic outcomes of the Nanos implant. Materials and Methods: We retrospectively reviewed 53 patients (35 males, 18 females) who underwent THA with the Nanos stem between 2008 and 2010. Patients were stratified into two groups according to age: <50 years (n = 24) and ≥50 years (n = 29). The primary diagnosis was osteoarthritis (95%), with a few cases of avascular necrosis or dysplasia. Clinical evaluation included the Harris Hip Score (HHS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Radiographic assessment focused on implant stability, osteolysis, and heterotopic ossifications. Kaplan–Meier survival analysis was performed with revision for any reason as the endpoint. Results: At 15 years of follow-up, both groups showed significant improvement (p < 0.001). In patients <50 years, HHS increased from 53.3 to 94.8 and WOMAC decreased from 79.9 to 3.5. In patients ≥50 years, HHS improved from 47.5 to 95.2 and WOMAC from 81.5 to 3.2. Radiographs confirmed stable fixation without osteolysis. Complications included two dislocations and one cortical perforation requiring revision. Kaplan–Meier survivorship at 15 years was 100% (<50) and 96.6% (≥50). Conclusions: The Nanos stem provided excellent long-term outcomes with low complication and revision rates. It should be considered one of several reliable short-stem options for younger, active patients, offering durable function while preserving bone stock. Full article

Background: Mixed martial arts (MMA) is becoming increasingly popular and is developing dynamically in terms of training methods and number of participants involved, while weightlifting, powerlifting, and other kinds of strength disciplines are well established. In this study, the aim was to compare the body composition, as an anthropometric effect of training in MMA fighters and strength athletes, and then analyze and find reasoning for observed differences. Methods: Thirty-four young healthy male participants (body weight 84.9 ± 10.2 kg, body height 182.0 ± 6.8 cm, BMI 25.8 ± 2.51 kg/m², tier 2/3 in McKay’s sports level classification) represented two groups: MMA (n = 17) and powerlifting athletes (STR, n = 17). The measured anthropometric characteristics were skeletal muscle mass (SMM), percentage of body fat (PBF), body fat mass (FM) and visceral fat mass (VFM). Phase angle (º) was measured as an indicator of tissue quality and we performed detailed investigations of soft fat-free tissue mass (SLM) and of fat mass in body parts separately in each lower and upper limb and trunk. Results: The groups did not differ in terms of body weight, height, BMI, SMM, PBF, FM, VFM, SLM in upper limbs and trunk, FM in the body parts, or the phase angle (all p > 0.05). The statistically significant differences were only observed in the SLM of both lower limbs (greater in STR, p < 0.05) but, after statistical correction with the Holm’s method, these parameters also did not show statistically significant differences despite high effect sizes. Conclusions: The MMA athletes do not differ significantly from strength training athletes in measured anthropometric parameters despite distinct differences in training methodology. The reasons for these observations need future research, combining anthropometric measurements with training and competing load monitoring. Full article

Background: The multifactorial nature of CrossFit performance remains incompletely understood, particularly regarding sex- and experience-related physiological and biomechanical factors. Methods: Fifteen trained athletes (8 males, 7 females) completed assessments of anthropometry, estimated one-repetition maximums (bench press, back squat, deadlift), squat jump (SJ), maximal oxygen uptake (VO₂max), ventilatory responses ($\dot{\mathrm{V}}$E), and heart rate (HR). Spearman, Pearson, and partial correlations were calculated with Holm and false discovery rate (FDR) corrections. Results: Males displayed greater body mass, lean and muscle mass, maximal strength, and aerobic capacity than females (all Holm-adjusted p < 0.01). Experienced athletes completed Fran faster than beginners despite broadly similar anthropometric and aerobic profiles. In the pooled sample, WOD time showed moderate negative relationships with estimated 1RM back squat (ρ = −0.54), deadlift (ρ = −0.56), and bench press (ρ = −0.65) before correction; none remained significant after Holm/FDR adjustment, and partial correlations controlling for training years were further attenuated. Conclusions: This exploratory study provides preliminary evidence suggesting that maximal strength may contribute to Fran performance, whereas conventional aerobic measures were less influential. However, given the very small sample (n = 15, 8 males and 7 females) and the fact that no relationships remained statistically significant after correction for multiple testing, the results must be regarded as preliminary, hypothesis-generating evidence only, requiring confirmation in larger and adequately powered studies. Full article

Background: In elite football, understanding how age impacts players’ physical performance is essential for optimizing training, career longevity, and team management. Objectives: This study aimed to compare variations in physical capabilities of professional football players by chronological age and identify peak performance ages. Methods: Data from 5203 match performances across 351 official games were analyzed, involving 98 male players aged 18–39 years. Physical capacities (speed, explosive actions, and endurance) were assessed using the Catapult VECTOR7 system. Results: showed that players over 32 years experienced declines in high-intensity and explosive actions, while endurance remained relatively stable with age. Peak performance occurred around 25.7 years for speed, 24.8 years for endurance, and 26 years for explosiveness. Conclusions: Overall, players aged 17–26 years demonstrated the highest physical performance, with notable declines observed in older age groups. Full article

Objective: This study aimed to experimentally investigate the biomechanical and performance differences between the grab start (GS) and the kick start (KS) with each leg on the kickplate (KSR, KSL) in Bi-Finswimming (BFS). It focused on the effect of foot placement on the starting block, equipped with an adjustable, inclined rear kickplate (Omega, OSB11), to determine potential performance advantages and contribute evidence-based recommendations for optimizing start techniques in competitive BFS. Methods: Thirteen national-level finswimmers (seven males, six females; age: 17.7 ± 2.1 years) voluntarily participated. Each athlete performed two trials of three start techniques (GS, KSR, KSL) over three days in a randomized order. Four synchronized cameras recorded video data. Performance metrics (time to 5 m (T5), 15 m (T15), 25 m (T25), reaction time, block time (BT), flight time (FT), and entry characteristics) along with joint angles (hip, knee, ankle), were analyzed using Kinovea software (v. 2024.1). A two-way repeated measures ANOVA (start type × gender) was conducted to analyze performance metrics, and a paired-sample t-test assessed differences in joint angles. Also, correlations between dependent (type of start) and independent variables (start-examined variables) were examined through bivariate Pearson’s r analysis. Results: No significant gender differences were found (p > 0.05). Significant differences emerged between the starting techniques, with KS showing faster T5, T15, and T25 (p < 0.001, η²_p = 0.6; p < 0.001, η²_p = 0.5; p < 0.05, η²_p = 0.3, respectively). BT was significantly longer in GS compared to KS (p < 0.001, η²_p = 0.8), while FT was shorter in GS (p = 0.002, η²_p = 0.4). Faster T5, T15, and T25 were associated with increased flight distance and longer FT in KSL. Conclusions: The kick start generally outperforms the grab start, especially in block time, in Bi-Finswimming. These preliminary results suggest that it could be considered for future discussion regarding potential legalization by the World Underwater Federation, pending further research. Full article

Objectives: The aim of this study was to compare the effects of eight-week hamstring stretching programs, implemented at different times during physical education classes (i.e., warm-up, cool-down, and both periods), on primary schoolchildren’s back-saver sit-and-reach scores. Methods: A total of 275 schoolchildren (141 females and 134 males; age 8.82 ± 1.63 years) were divided into four groups: the WUG performed stretching during warm-up, the CDG during cool-down, and the MXG during both. The NSG followed the standard classes of physical education without any stretching. During physical education classes WUG, CDG, and MXG performed a 4 min stretching program twice a week. Hamstring extensibility was assessed before and after the program using the back-saver sit-and-reach test. Results: The CDG is the one that achieved statistically significant improvements compared with the WUG, MXG, and NSG (p ≤ 0.01; d = 0.50–0.71). Moreover, the CDG statistically increased the percentage of schoolchildren achieving healthy hamstring extensibility from pre-intervention (49%) to post-intervention (66%). Conclusions: This knowledge could guide teachers to design programs that guarantee feasible and effective development of hamstring extensibility in the physical education setting. Full article

Background: Basketball is characterized as a high-intensity, intermittent sport that places considerable demands on the cardiorespiratory, neuromuscular, and mechanical systems. These physiological requirements are modulated by contextual variables and the athlete’s stage of biological maturation, both of which significantly influence physical fitness outcomes. Consequently, it is imperative to employ age- and development-specific assessment protocols. Objectives: This study aimed to evaluate the differences in physical fitness across competitive categories and to explore the interrelationships among the various physical assessment tests. Twenty-four male players (U14 = 12; U16 = 12) participated in this research. Methods: Athletes were monitored using WIMUPRO inertial measurement units and completed the SBAFIT test battery to evaluate physical fitness parameters. Statistical analyses included both inferential and correlational approaches, with effect sizes calculated for all relevant variables. The independent variable was the competitive age category of the players. Results: The results indicated notable differences in physical performance between developmental groups, primarily attributed to biological maturation. Significant disparities were observed in measures of aerobic capacity, linear speed, agility, and centripetal force. Conclusions: The comparative nature of this study across developmental categories offers novel insights and practical implications for talent development and training optimization. Full article