Search Results (80)

This study examines the impact of support leg kinematics on kicking performance and its direct relationship with ball velocity and spin. Seventy-eight players performed maximal instep kicks each with their preferred and non-preferred leg, which were recorded with a three-dimensional motion capture system. Linear mixed models were used to analyze the effects of discrete data of lower limb on ball velocity and spin. Professional male players exhibited significantly smaller hip internal-external rotation range of motion (ROM) and angular velocity compared to other groups (p < 0.05). In professional players, the preferred leg kicks showed greater knee flexion-extension ROM, flexion angular velocity, and extension angular velocity than the non-preferred leg kicks (p < 0.01). Regression analysis revealed that hip and knee extension angular velocities, as well as knee flexion-extension ROM, positively influenced kicking performance, while hip adduction-abduction ROM had a negative impact. These findings emphasize the critical role of the support leg in modulating ball velocity, ball spin, and stability during instep kicking. Training should prioritize hip and knee extension strength for power generation and frontal plane stability for postural control. This study offers novel insights into support leg kinematics across competitive levels, with implications for coaching and performance enhancement. Future research should explore phase-specific support leg dynamics during kicking. Full article

Objectives: Taekwondo performance is influenced by a complex and dynamic interplay of physical, nutritional, and psychological factors, all of which contribute to competitive success. However, the gender-specific relationships among these factors in young high-performance athletes remain understudied. This study aimed to fill in this knowledge gap. Methods: A cross-sectional study was conducted with 35 elite taekwondo athletes (male: n = 20, female: n = 15, age: 13 ± 1 years). Participants underwent anthropometric assessments, dietary evaluations, and psychological skill assessments during an 8-week training camp before the World Taekwondo Championships. Physical performance was assessed using the Frequency Speed of Kick Test (FSKT_mult) and the Taekwondo-Specific Agility Test (TSAT). Statistical analyses included independent t-tests, correlation analyses, and regression models. Results: Males exhibited significantly higher fat-free mass (FFM: 42.8 ± 2.9 kg vs. 36.3 ± 1.6 kg, p < 0.001), skeletal muscle mass (SMM: 31.1 ± 2.2 kg vs. 28.2 ± 1.6 kg, p < 0.001), and energy intake (32.4 ± 4.6 kcal/kg vs. 29.3 ± 3.1 kcal/kg, p = 0.032) than females. Males also had greater dietary intakes of vitamin A, vitamin C, magnesium, and iron (all p < 0.05). There were no gender differences in any psychological attributes associated with emotional intelligence, sport success perception, and mental toughness. Although the total kick count in the FSKT_mult was similar for male and female taekwondo athletes (100.2 ± 4.6 vs. 97.5 ± 5.9 kicks, p = 0.139), males outperformed females in round 4 (19.4 ± 1.1 vs. 18.6 ± 1.4 kicks, p = 0.048) and round 5 (18.2 ± 1.0 vs. 17.2 ± 1.0 kicks, p = 0.007) of this test, suggesting higher physical performance maintenance during the test. Regression models indicated that body mass (β = 0.901, p < 0.001) and calcium intake (β = 0.284, p = 0.011) predicted performance in males, while body mass (β = 1.372, p < 0.001), protein intake (β = 0.171, p = 0.012), and emotional regulation (β = 0.174, p = 0.012) were key predictors in females. Conclusions: These findings highlight the importance of an integrated approach to training, nutrition, and psychological preparation in optimizing taekwondo performance. While males and females demonstrated similar psychological resilience and total kick output in a taekwondo-specific test, males exhibited superior endurance in later test rounds of this test. Performance optimization in young elite taekwondo athletes may require the implementation of gender-specific training and nutrition strategies, emphasizing body weight control and calcium intake for males and protein intake for females. Full article

Background: Considering that the nervous system regulates cardiac autonomic modulation (CAM) and that low CAM is associated with poorer performance, it is essential to evaluate the effects of training to increase parasympathetic modulation in Muay Thai (MT) fighters. Therefore, the aim of this study was to evaluate the effects of an 8-week intervention based on strength training and nutritional counseling on performance, CAM, and nutritional status in amateur MT fighters. Methods: This is a longitudinal and interventional study in which 22 MT fighters underwent a strength training program and nutritional protocol. Before and after the intervention, they underwent the ten-second frequency speed of kick test (FSKT-10s), multiple frequency speed of kick test (FSKT-mult), bioimpedance analysis (BIA), and assessment of heart rate variability. Results: After the intervention, there was an increase in the number of kicks in both FSKT-10s and FSKT-mult (p = 0.0008 and p = 0.032, respectively). In BIA, there was a significant increase in both fat-free mass and basal metabolic rate (p = 0.031 and p = 0.020, respectively). After the intervention, significant increases were observed during the physical test in the following variables that denote improvement in parasympathetic modulation: square root of the mean squared differences of successive RR intervals (p = 0.005); percentage of adjacent RR intervals with a difference in duration greater than 50 ms (p = 0.002); high frequency range (p < 0.0001); and standard deviation measuring the dispersion of points in the plot perpendicular to the line of identity (p = 0.004). Conclusions: In amateur MT fighters, an intervention with strength training and nutritional guidance is able to improve CAM through greater parasympathetic activation. Furthermore, there is an improvement in performance and body composition after the intervention. Full article

In combat sports, precise technique evaluation is crucial for performance optimization; however, traditional systems for evaluating kick performance are frequently unreasonably complicated and costly. This study offers a useful and accessible substitute by introducing a contact mat-based tool that measures the roundhouse kick’s execution time during both the attack and recovery phases and by demonstrating its reliability. The experimental sessions involved 16 male Shotokan karate athletes (age: 25.6 ± 7.1 years; height: 1.74 ± 0.05 m; body mass: 71.5 ± 8.7 kg; body fat percentage: 14.7 ± 6.7%; training experience: 11.0 ± 4.9 years). The protocol included four sessions, starting with a familiarization phase followed by three testing sessions (test, retest, and retest two), during which a standardized warm-up was performed along with the roundhouse kick test. The intraclass coefficient correlation (ICC) used indicated high reliability for the at-tack (ICC = 0.85, 95% CI [0.64, 0.94]), recovery (ICC = 0.89, 95% CI [0.75, 0.96]), and total time (ICC = 0.90, 95% CI [0.76, 0.96]). The Friedman test revealed no significant difference between testing sessions (p > 0.31), demonstrating high reliability and no significant differences between sessions. This study confirms the system as a simple and reliability tool for measuring roundhouse-kick timing in combat sports. Full article

Complete fractures of the third metacarpal bone (MC III) diaphysis pose a significant clinical challenge, prompting advanced veterinary medicine to utilize constitutive and biomechanical modeling to better understand bone behavior. This study aims to compare the elastic modulus of the MC III cortical bone, supported by measurements of cortical bone thickness and relative density, across the dorsal, lateral, medial, and palmar aspects of the MC III, as well as to evaluate the cortical bone’s response to compressive forces applied in different directions. Given the bone structure can exhibit sex-related differences, MC III bones were isolated from six equine cadaver limbs collected exclusively from mares and imaged using computed tomography (CT) to measure thickness and density. Cortical bone samples were collected from the four aspects of the MC III and subjected to mechanical testing followed by the elastic modulus calculation. Bone thickness and elastic modulus varied across the MC III aspects. Thinner cortical bone on the palmar aspect coincided with a lower sample reaction force-based elastic modulus in the externo-internal direction and a lower axial compression force elastic modulus in the proximo-distal direction. Regardless of the MC III aspect, the cortical bone demonstrated greater resistance to compressive forces when loaded in the vertical plane than in the horizontal plane. The returning of different values in mechanical tests depending on the direction of loading may be attributed to the anisotropic behavior of the cortical bone, which may implicate the increased risk of complete fractures of the MC III diaphysis due to a kick from another horse or a fall, rather than from training or competition-related overload. Full article

Background/Objectives: The purpose of this study was to assess the body posture of kickboxing players. Methods: The study group included people training as kickboxers who actively participated in the training camp of the broad national junior team in the K1 and low-kick kickboxing leagues. The control group consisted of non-training people. The age of the study group ranged from 15 to 23 years. The ages of the control group participants varied from 14 to 20 years. A body posture test was performed by using the Moiré method, in accordance with the guidelines of the manufacturer of the Moiré 4G device. Results: The body posture test performed using the Moiré method showed statistically significant differences between the kickboxing training group and the control group. The parameters that showed statistically significant differences included the size of lordosis (KLL) and the depth of lordosis (GLL) in the lumbar spine. Higher values were observed in the kickboxing training group compared to the control group. There was no statistically significant difference between the kickboxing group and the control group in other parameters. Conclusions: The asymmetrical and flexed posture required during kickboxing training did not negatively influence the competitors’ spinal curvatures. Kickboxers had increased lumbar lordosis, which may be related to the specificity of the given discipline (stretching of the hamstrings and specific movements). This is a beneficial phenomenon that may reduce the risk of lower back pain. Kickboxing training did not affect the asymmetry of body posture in the sagittal plane. Full article

Background: In karate, the ability to execute high-velocity movements, particularly kicks and punches, is heavily dependent on the strength and power of the lower limb muscles, especially the knee extensors. As such, this study aimed to evaluate the effects of an 8-week eccentric training program utilizing the reverse Nordic exercise (RNE) integrated into karate training compared with regular karate training only on measures of physical fitness in youth karate athletes. Methods: Twenty-seven youth karatekas were recruited and allocated to either RNE group (n = 13; age = 15.35 ± 1.66 years; 7 males and 6 females) or an active control group ([CG]; n = 14; 7 males and 7 females; age = 15.30 ± 1.06 years). To track the changes in measures of physical fitness before and after training, tests to assess linear sprint speed (i.e., 10 m), change of direction (CoD) speed (i.e., modified 505 CoD), vertical jumping (i.e., countermovement jump [CMJ] height) and horizontal jumping distance (i.e., standing long jump [SLJ]), and lower-limb asymmetry score (i.e., the difference between SLJ-dominant and non-dominant legs) were carried out. Results: The results indicated significant group-by-time interactions in all measures of physical fitness (effect size [ES] = 1.03 to 2.89). Post-hoc analyses revealed significant changes in the RNE group across all performance measures (effect size [ES] = 0.33 to 1.63). Additionally, the asymmetry score exhibited a moderate decrease from pre to posttest (∆46.96%, ES = 0.64). In contrast, no significant changes were observed in the CG across all fitness measures. Moreover, the individual response analysis indicated that more karatekas from the RNE group consistently achieved improvements beyond the smallest worthwhile change threshold across all fitness measures. Conclusions: In summary, RNE training is an effective approach to enhance various physical fitness measures besides lower-limb asymmetry scores in youth karatekas and is easy to incorporate into regular karate training. Practitioners are therefore encouraged to consistently integrate RNE training to enhance essential physical fitness components in young karatekas. Full article

The Multiple Frequency Speed of Kick Test (FSKT_mult) is used to investigate which characteristics are necessary for, contribute to, or limit the ability to repeat high-intensity intermittent efforts in taekwondo. This cross-sectional study investigated the relationship between anthropometric and body composition characteristics, muscle power performance, and sport-specific anaerobic performance. Nineteen black belt taekwondo athletes (mean ± SD age: 17.2 ± 2.4 years) volunteered to participate. Anthropometric and body composition characteristics (i.e., body height (BH), body mass (BM), fat mass (FM), body fat (BF%), and muscle mass (MM)) and physical performance (squat jump (SJ), countermovement jump (CMJ) tests, and FSKT_mult) were assessed. Data were analyzed with correlation coefficients and simple linear regression. The statistical significance was set at p < 0.05. The total number of kicks in FSKT_mult (FSKT_total) was significantly and positively correlated with MM (r = 0.521, R² = 0.27, p < 0.05) and negatively with BF% (r = −0.499, R² = 0.25, p < 0.05). The FSKT_total was significantly and positively correlated with SJ (r = 0.520, R² = 0.27, p < 0.05) and CMJ (r = 0.508, R² = 0.26, p < 0.05) performance. Body composition optimization, with appropriate physical training and dietary planning, is relevant in taekwondo as the improvement in the ability to repeat high-intensity intermittent efforts depends on MM, and its worsening on BF%. Lower limb muscle power positively influences the ability to repeat high-intensity intermittent efforts. Therefore, training programs should emphasize ballistic and plyometric exercises. Full article

The Sichuan Basin has abundant deep and ultra-deep natural gas resources, making it a primary target for exploration and the development of China’s oil and gas industry. However, during the drilling of ultra-deep wells in the Sichuan Basin, complex geological conditions frequently lead to gas kicks, posing significant challenges to well control and safety. Compared to traditional kick detection methods, artificial intelligence technology can improve the accuracy and timeliness of kick detection. However, there are limited real-world kick data available from drilling operations, and the datasets are extremely imbalanced, making it difficult to train intelligent models with sufficient accuracy and generalization capabilities. To address this issue, this paper proposes a kick data augmentation method based on a time-series generative adversarial network (TimeGAN). This method generates synthetic kick samples from real datasets and then employs a long short-term memory (LSTM) neural network to extract multivariate time-series features of surface drilling parameters. A multilayer perceptron (MLP) network is used for data classification tasks, constructing an intelligent kick detection model. Using real drilling data from ultra-deep wells in the SY block of the Sichuan Basin, the effects of k-fold cross-validation, data dimensionality, various imbalanced data handling techniques, and the sample imbalance ratio on the model’s kick detection performance are analyzed. Ablation experiments are also conducted to assess the contribution of each module in identifying kick. The results show that TimeGAN outperforms other imbalanced data handling techniques. The accuracy, recall, precision, and F1-score of the kick identification model are highest when the sample imbalance ratio is at 1 but decrease as the imbalance ratio increases. This indicates that maintaining a balance between positive and negative samples is essential for training a reliable intelligent kick detection model. The trained model is applied during the drilling of seven ultra-deep wells in Sichuan, demonstrating its effectiveness and accuracy in real-world kick detection. Full article

Maximal athletic performance can be limited by various factors, including restricted respiratory function. These limitations can be mitigated through targeted respiratory muscle training, as supported by numerous studies. However, the full potential of respiratory training in competitive finswimming has not been fully investigated. This case study aims to evaluate the effects of eight-week respiratory muscle training (RMT) on performance variability during the underwater phases of a 200 m bi-fins race simulation in an elite finswimmer (current world record holder and multiple world championship medalist). Performance variability was assessed based on pre-test, inter-test, and post-test data. Each measurement included pulmonary function and swim performance evaluations. In this study, underwater performance parameters, such as distance, time, velocity, and number of kicks, were assessed using video analysis synchronized with race timing and evaluated using the Dartfish software. The swimmer followed a 28-day training program with an Airofit PRO™ respiratory trainer between tests, with daily sessions targeting both inspiratory and expiratory muscles. The training involved 6–10 min of targeted exercises per day. Significant improvements were observed in Wilcoxon’s paired-sample test between the pre-test and post-test results in terms of underwater distance (p = 0.012; d = 1.26), underwater time (p = 0.012; d = 1.26), and number of underwater kicks (p = 0.043; d = 1.01), resulting in a 14.23% longer underwater distance, 14.08% longer underwater time, and 14.94% increase in underwater kicks. Despite the increased distance and time, underwater velocity remained stable, indicating improved underwater performance efficiency. Despite some improvements, it is not possible to conclude that respiratory muscle training (RMT) can contribute to improved finswimming performance during the underwater phases of a 200 m bi-fins race simulation in this particular athlete’s case. Further research with a larger sample size is necessary to fully understand the impact of RMT on finswimming performance. Full article

This review explores the prevalence and impacts of muscular power and dynamic balance motor asymmetry among football players, emphasizing its impact on performance and injury risk. Motor asymmetry frequently occurs in football, largely due to the sport’s specific demands, including the frequent use of one leg for kicking and passing. While some motor asymmetry may lead to functional specialization and does not always hinder performance, significant imbalances are often linked to an increased risk of injuries, particularly to the lower extremities. Dynamic balance motor asymmetry is also associated with a higher risk of non-contact injuries, underscoring the importance of joint stability in preventing such injuries. However, the direct impact of balance motor asymmetry on performance metrics like sprint speed and agility is less definitive, suggesting that compensatory mechanisms or training adaptations could mitigate potential negative effects. Technological advances in assessment, such as motion capture systems and wearable devices, have enhanced the precision of asymmetry evaluations, enabling more targeted interventions. In addition, personalized training interventions, informed by real-time data from these technologies, allow for tailored rehabilitation and performance optimization, addressing asymmetry-related risks early. Despite these technological advancements, there is a significant gap in understanding how motor asymmetry affects underrepresented groups, such as female football players and youth athletes. Further research is needed to investigate motor asymmetry in these populations, particularly to assess the long-term impact on injury risk and performance. Addressing these gaps will provide valuable insights into the development of gender- and age-specific training interventions. This review recommends a multidisciplinary approach, integrating biomechanics, sports medicine, and coaching insights, to develop comprehensive strategies for managing motor asymmetry in football. Such strategies, supported by real-time monitoring and tailored interventions, will be crucial for optimizing player performance, minimizing injury risk, and improving training and rehabilitation programs tailored to the diverse needs of football players. Full article

Training in team sports such as soccer requires advanced technical and tactical skills for effective decision-making, particularly when executing a shot. This study validates an innovative instrument, a training platform (TP), designed to measure and enhance decision-making in dual-task scenarios. The TP aims to improve visual–motor reactions in multitask environments that simulate real game conditions. Equipped with an LED panel, main circuitry, ball sensor, and targets, the TP challenges players to kick the ball in response to the illumination of the final LED array on the panel while hitting a designated target. The study evaluated three parameters: reaction time (RT), ball speed (BS) and accuracy. To validate the TP against a gold standard (GS), we conducted correlation analyses. The results exhibited very strong correlations for both RT (r = 0.997) and BS (r = 0.994). The mean differences between TP and GS measurements were 13 ± 15 ms for RT and 0.1 ± 0.5 km/h for BS. Bland–Altman plots revealed trend lines obtained by a simple linear regression of r = −0.507, p = 0.307 for RT and r = 0.134, p = 0.077 for BS. The TP effectively simulates game scenarios, offering advantages such as low-cost components, installation flexibility, test variability, instant feedback, and integration of physical and cognitive components of sports performance. Full article

The ATP-PCr system represents the main source of energy during high-intensity attack actions in taekwondo matches. In contrast, the glycolytic system supports the maintenance of these actions when repeated techniques are performed. Given the close relationship between anaerobic energy systems and attack activity in combat, the literature relating to the use of sport-specific test protocols for anaerobic assessment has experienced a remarkable increase. This narrative review aims to illustrate the sport-specific anaerobic tests available in taekwondo by retracing and examining development and validation process for each test. Forty-one articles published between 2014 and 2023 were selected via the MEDLINE and Google Scholar bibliographic databases. These tests are the Taekwondo Anaerobic Test and Adapted Anaerobic Kick Test (i.e., continuous mode testing); the 10 s and multiple Frequency Speed of Kick Tests; the chest and head Taekwondo Anaerobic Intermittent Kick Tests; and the Taekwondo-Specific Aerobic–Anaerobic–Agility test (i.e., intermittent mode testing). Coaches and strength and conditioning professionals can use all the tests described in taekwondo gyms as they feature short and easy-to-implement protocols for monitoring and prescribing specific anaerobic training. The guidelines in this review evaluate each test from several perspectives: basic (e.g., validity, reliability, and sensitivity), methodological (e.g., continuous or intermittent mode testing) and application (e.g., time–motion structure and performance parameters). This comprehensive approach aims to assist stakeholders in selecting the most appropriate test. Full article

(1) Background: The kick of the ball in soccer is considered one of the most important technical gestures in soccer. Despite this, there is little evidence on ball-striking performance factors in base soccer. The main objectives of the present study were to identify the potential factors of long-ball kicking (LBK) performance and to determine the target training cut-off for LBK performance in young soccer players. (2) Methods: A cross-sectional observational study was conducted with 31 soccer players, with ages ranging from 12 to 18 years. Age, anthropometric data, sport experience, range of motion (ROM) and maximal isometric strength (MIS) of the lower limb were noted. Kick-of-the-ball performance was assessed by maximum ball displacement per kick. A k-mean cluster analysis determined two groups according to ball-kicking performance: low group (LPG-LBK) and high group (HPG-LBK). (3) Results: Differences were found between both groups in age, body mass, body mass index, leg length and knee flexion ROM (BF10 ≤ 6.33; δ ≥ 0.86 (moderate or higher)). Among the factors discussed above, age was the strongest predictor of ball-striking performance (odds ratio = 2.867; p = 0.003). The optimal cut-off for age predicting those players most likely to have a higher ball-striking performance was determined to be 13.5 years (p = 0.001; area under the curve = 85.3%). (4) Conclusions: Age over 13.5 increases the chances of a higher optimal ball-striking performance. The flexibility (knee flexion ROM) and strength (knee flexors) must be specifically trained in soccer players beginning at an early age. Full article

Hamstring injuries (HSIs) are prevalent in sports that involve changes in direction, kicking, and sprinting. These injuries are a major cause of time lost from competition, practice, and training, as well as increased healthcare costs. In a Division I collegiate football program, the authors implemented a multifactorial approach that included repeated performance assessments, detailed data analysis, and a flexible strength and conditioning regimen. Over a three-year period, this resulted in no game time loss due to HSI. This model can be adapted and implemented across sports settings. Full article