The increase in the competitive level and popularity of handball necessitates the optimization of training methods, particularly in the development of explosive strength, which determines jump effectiveness and overall game performance. This study analyzed the impact of specific power training and conventional resistance training on jumping abilities of young handball players. A total of 48 athletes were selected for the experiment and randomly assigned to a power training (PT) group, a resistance training (RT) group, or a control (C) group. The training program included plyometric exercises, dynamic neuromuscular activations, and reaction-time-based stimuli, with their effects evaluated through vertical jump tests (CMJ and SJ). The results indicated significant increases in jump height, maximum power, and relative maximum power in the PT group (p < 0.05), suggesting that specific power training more effectively supported the development of dynamic variables than standard resistance training methods. While the RT group demonstrated gains in strength, the corresponding improvements in vertical jump performance were modest and not as substantial as those seen in the power training group. The findings highlight the crucial role of neuromuscular mechanisms in generating explosive power, as well as the importance of training methods based on the stretch-shortening cycle.
Precise timing of ball-racket contact is a critical determinant of stroke performance in tennis, yet few studies have objectively quantified this variable across different players’ groups. This study developed and validated a hybrid vision-based framework combining K-nearest neighbors (KNN) background subtraction with Hue-Saturation-Value (HSV) color segmentation to analyze the spatial relationship between the contact point and the apex of the ball’s trajectory. Twelve participants were recruited and stratified by skill level and gender, each performing 30 forehand and 30 backhand strokes, yielding 720 stroke events. Contact point overlap ratios and vertical height distributions were extracted, and two-way ANOVA was used to examine main and interaction effects. Results indicated a significant effect of the skill level, with top-level players demonstrating higher overlap ratios and reduced vertical deviations compared to average-level players (p < 0.001, partial η² = 0.386). Gender differences were negligible among top-level players but pronounced in the average-level group, particularly for backhand strokes (p < 0.001). These findings highlight the skill level as the dominant factor influencing contact point precision, while gender disparities emerge primarily among less experienced athletes. The proposed computer vision approach offers a low-cost and scalable tool for objective stroke assessment and has potential applications in individualized training feedback and performance monitoring.
Indoor tracking systems of varying technological complexity are commonly used to quantify physical demands in team-handball. However, there is a lack of research concerning IMU based tracking systems. Therefore, the aim of this study was to evaluate a recent IMU tracking system in team-handball. The evaluation steps included the examination of (i) the agreement between an established LPS+IMU and the IMU tracking system, (ii) the correlation structure of investigated variables, and (iii) differences between training drills using the IMU system. A total of 34 handball players from the female U18 and male U21 national teams of the German Handball Federation participated. Three training sessions including seven training drills and one simulated match were recorded using an established LPS+IMU and the recent IMU tracking system. Results showed that (i) the accumulated player load and time spent in the low speed zone presented substantial agreements (CCC > 0.95), (ii) the accumulated player load was highly correlated with total distance and time spent in very low, low, and very high speed zones (r ≥ 0.61), and (iii) accumulated player loads were highest in training drills covering the entire court. In German junior female and male national handball players, the recent IMU tracking system only allowed a valid assessment of variables that were directly assessed by the measurement technology, i.e., the accumulated player load. However, the player load indicated more the volume than the intensity of training and matches, which should be considered by coaches and scientists when monitoring physical demands in junior handball players.
Depending on the motor task or the situation, visual stimuli may facilitate or hinder task performance. The purpose of this study was therefore to investigate the role of vision in CMJ performance. The study was conducted on a group of 30 physically active men (age: 21.5 ± 1.1 years, body height: 1.83 ± 0.07 m, body mass: 78.6 ± 10.7 kg) with no visual impairment and high jumping abilities. All participants performed a total of 12 CMJs: 6 under a full-vision condition (FV) and 6 under a no-vision condition (NV), in randomized order. Measurements were conducted using two Kistler 9286A force plates with Noraxon MR3 software. No significant differences were found in jump height (JH), mean power (MP) in the propulsion phase, propulsive time (PT), countermovement depth (CD) or countermovement time (CT) between the FV and NV conditions. Under the FV condition, peak power (PP) in the propulsion phase was by 87 ± 222 W higher than under the NV condition (p < 0.05 with small effect size). Furthermore, the relationships among the variables describing the CMJs (JH, PP, MP, PT, CD, and CT) under the FV and NV conditions were large, very large or nearly perfect (p < 0.001). The results show that eliminating visual stimuli may not have a negative impact on CMJ performance. On the contrary, eliminating visual stimuli can reduce interference that negatively affects maximum performance (e.g., maximum jump height). This surprising observed phenomenon may be possible due to the important role played by the proprioceptive system and kinesthetic feedback.
This study aimed to identify the key technical and training-related factors that differentiated among performance levels in short-course (25 m) 100-m breaststroke swimmers. Sixteen male athletes were divided into two groups: Level 3 (682.3 ± 42.3 FINA points) and Level 4 (574.4 ± 28.7 FINA points). Anthropometry, muscle force characteristics, stroke efficiency, and underwater performance were assessed under competition conditions. A Bayesian regression model revealed that Level 3 swimmers achieved significantly faster 100-m times than Level 4 swimmers (β = 1.16, SE = 0.36, 95% CI [0.43, 1.87]). No significant between-group differences were observed in maximum voluntary force (Fmax), the rate of force development (RFD), or basic anthropometric variables, suggesting that strength and body size alone did not explain performance disparities. In contrast, Level-3 swimmers demonstrated a superior stroke index in the first half of the race, as well as significantly greater start-dive velocity and turn-dive length. Bayesian regression confirmed a decisive interaction between turn-dive length and start-dive velocity (β = −0.41, SE = 0.09, 95% CI [−0.59, −0.23]), underscoring the importance of efficient underwater transitions. These findings suggest that beyond a certain threshold, additional strength may not translate into faster race times, whereas technical skill, neuromuscular coordination, and efficient glide mechanics are decisive in short-course performance. Future studies should integrate fat-free mass and drag coefficient measures for a more comprehensive profile of performance determinants, and examine whether the dominance of underwater phases persists in long-course (50 m) pools, where stroke efficiency and in-swim propulsion may play a greater role.
Hyperbaric Oxygen Treatment (HBOT) is a therapeutic method that combines the effects of hyperoxia and increased pressure. This clinical trial aimed to assess how ten HBOT sessions would influence body composition and physical performance of healthy young men, and whether the frequency of treatment would affect these outcomes. Healthy adult males were enrolled and randomized into three groups: a control group (n = 15), frequent HBOT users (six sessions per week; n = 20), and rare HBOT users (three sessions per week; n = 19). Participants in the intervention groups received ten 60-min sessions of 100% oxygen at a pressure of 2.5 atmospheres absolute (ATA). Participants underwent body composition evaluation and performed an incremental treadmill test before and after the intervention. Marginal but statistically significant reductions in body mass and the body mass index (BMI) were observed only in the rare HBOT users. In both intervention groups, but not in the control group, a significant increase was noted in the maximal speed and distance covered during the treadmill test. Additionally, rare HBOT users showed a significant increase in relative maximal oxygen uptake, while absolute VO₂max remained unchanged. The main finding of our study was that ten hyperbaric oxygen treatments did not significantly enhance body composition or physical capacity in healthy young men. Furthermore, our study showed no indications for the daily HBOT administration in healthy individuals; instead, the findings suggested potential benefits from a less frequent, extended treatment protocol.
This study compared the effects of velocity-based training (VBT) and percentage-based training (PBT) on lower-body strength and the sticking region in squat exercises among resistance-trained males over a six-week intervention. Twenty resistance-trained males were randomized to train in a 10% velocity loss threshold VBT group (n = 10, age = 21.96 ± 2.27 years, body height = 1.79 ± 0.04 m, body mass = 70.98 ± 6.16 kg) or a traditional PBT group (n = 10, age = 22.12 ± 2.38 years, body height = 1.78 ± 0.02 m, body mass = 74.14 ± 4.87 kg), each training twice weekly for six weeks. Changes in the squat one-repetition maximum (1RM), relative strength, the countermovement jump (CMJ), the standing long jump (SLJ), duration of the sticking region, and average velocity in the sticking region were measured using pre- and post-tests. Results indicated significant improvements in the squat 1RM, relative strength, and the CMJ for both groups, with no significant changes in sticking region velocity (p > 0.05). Except for squat 1RM improvements (p < 0.01), no other significant differences were noted between groups post-intervention (p > 0.05). In conclusion, both interventions significantly enhanced lower-body strength, with the VBT regimen showing greater effectiveness. Neither approach significantly altered the duration or velocity of the sticking region, though the PBT regimen yielded more favorable improvements in sticking region performance. These findings suggest that differences in muscle adaptation and strength qualities between regimens might explain the varied impacts on the sticking region. Future research could explore these aspects to further refine training strategies for improving sticking region performance across various movement phases.
This study aimed to compare inhibitory control, perceived exertion, subjective mental fatigue, and countermovement jump (CMJ) height in young soccer players following three different conditioning activities: (a) a coordinative task, (b) sprinting, and (c) a combination of coordinative and sprint tasks. Twenty-five under-15 soccer players participated in four randomized and crossover experimental conditions: Coordinative (COORD), Sprint (SPRT), Combined (COMB), and Control with low cognitive demand (CONT). Before and after each warm-up activity, the following variables were measured: perceived exertion, perceived mental fatigue, CMJ height, stroop test response time, and accuracy. Generalised Estimating Equations analysis revealed a main effect of time for perceived exertion (p < 0.001), perceived mental fatigue (p < 0.001), the CMJ (p < 0.001), and response time (p = 0.012). After performing the SPRT and COMB warm-ups, players reported higher perceived exertion and reduced CMJ performance when compared to the other experimental conditions (p < 0.05). Greater subjective mental fatigue was observed following the COORD and COMB warm-ups than the CONT experimental condition (p < 0.05). However, only the COMB condition resulted in increased response time for the inhibitory control when compared to the CONT condition (p < 0.05). Caution is warranted when incorporating COMB warm-ups into training sessions that are followed by tasks requiring both physical and cognitive effort.
Pacing strategies are important factors for running performance and have been studied over the years. Nevertheless, whether the implementation of such strategies is crucial at ultramarathons under extreme weather conditions remains unclear. The purpose of this study was to investigate the use of running pace strategies in ultramarathons performed under very hot or cold weather conditions. Data from Desert Ultra 2022 and 2023 and Ice Ultra 2023 and 2024, each covering approximately 250 km during five consecutive days, were analyzed. Data from 143 runners included sex, finish time, pace, velocity, the number of runners who did not finish the ultramarathon, and the number of runners who did not start the ultramarathon. Participants were categorized into top 3, top 10, and top 20. Finish times were no equivalent between events (Ice Ultra; 43:47 ± 7:02 h:min vs. Desert Ultra; 48:10 ± 8:27 h:min; p = 0.002). The top 3 participants exhibited higher velocity in multiple stages compared with the other groups (p < 0.01). In top 20 runners, maintenance of the velocity pattern throughout the days was evident. However, the Ice Ultra group exhibited a decline in velocity between stages 1 and 2 (Δtop 3: 2.23 ± 0.14 km/h; Δtop 10: 2.11 ± 0.15 km/h; Δtop 20: 1.19 ± 0.18 km/h). Higher densities showed high heterogeneity among runners regardless of desert or ice running. Relief and weather are important factors in pacing strategies. Ice Ultra runners displayed a parabolic running strategy. In the Desert Ultra race, a substantial reduction in speed was observed even when there was no slope and even halfway through the completion of the pacing strategy stages. Managing fatigue from previous stages and temperature fluctuations are relevant factors that can be better explored.
While the influence of the load on mechanical outcomes has been investigated in weightlifting pulling derivatives, knowledge of these relationships in overhead pressing derivatives remains limited. To address this gap, this study examined the effects of varying loads on the force-time characteristics associated with peak power output in the behind-the-neck push jerk (BNPJ). Sixteen recreational male athletes were recruited and performed three repetitions of the BNPJ at 40%, 50%, 60%, 70%, and 80% of their 1RM. Mean system velocity (MSV), propulsive phase time (Time), peak force (PF), mean force (MF), peak power (PP), mean power (MP), the impulse and depth were calculated from force-time data during the propulsive phase and compared across loads. A series of one-way repeated measures analysis of variance (ANOVA) was used to compare the differences in each variable across intensities. The level of significance was set at p ≤ 0.05. Except for MSV, all variables progressively increased with loads. PF, MF, PP, MP, and the impulse were greatest at 80% 1RM with small to large significant differences between other intensities (p = 0.00–0.02, Hedge’s g = 0.26–2.49). There were no significant differences between 70% and 80% 1RM in PV (p = 0.35, g = 0.18), but there were significant differences between 80% 1RM and 40%, 50%, and 60% 1RM (p = 0.01–0.05, g = 0.14–0.64). Prescribing the BNPJ at 80% 1RM is beneficial in enhancing power and force output.
This study sought to investigate the genotypic and allelic frequencies of ACE I/D polymorphisms in elite Moroccan road cyclists and field hockey players. Forty-three Moroccan elite male athletes (19 cyclists; 24 field hockey players) and 28 healthy non-athletes were recruited for the study. All participants underwent ACE I/D polymorphism genotyping by the polymerase chain reaction (PCR) using genomic DNA from blood samples. The genotypic distribution of the ACE I/D polymorphism was similar in elite athletes (DD: 46.50, ID: 44.20, II: 9.30%) and controls (DD: 42.90, ID: 46.40, II: 10.70%; X2 = 0.103, p = 0.949). The allelic distribution was also similar in elite athletes (D allele; 68.60, I allele: 31.40%) and controls (D allele; 66.07, I allele: 33.93%; X2 = 0.099, p = 0.752) as well as cyclists (D allele; 63.16, I allele: 36.84%) and field hockey players (D allele; 72.92, I allele: 27.08%; X2 = 0.937, p = 0.332). These novel data indicate no significant differences in the genotypic and allelic frequencies of the ACE I/D polymorphism between athletes and controls or between elite road cyclists and field hockey players of Moroccan origin.
This study investigated how visual information blocking influenced drop jump (DJ) performance and lower limb mechanics, with a specific focus on its impact on stretch-shortening cycle (SSC) efficiency and neuromuscular adaptation in plyometric training. Fourteen male students (age: 22.0 ± 2.2 years; body height: 174.8 ± 2.4 cm; body mass: 70.3 ± 4.8 kg) performed DJs from a 0.3 m platform under normal and blind conditions. The DJ-index (jump height/contact time), joint kinematic and kinetic variables were measured. The blind condition resulted in a significantly lower DJ-index (p < 0.001) and longer contact time (p < 0.001), while jump height remained unchanged. Knee flexion (p = 0.028), hip flexion (p = 0.014), and knee extension (p = 0.046) increased significantly. Peak (p = 0.011) and mean (p = 0.006) ground reaction forces, as well as ankle joint kinetics were lower under blind condition. These results suggest that visual feedback enhances SSC efficiency by regulating lower limb joint movement and force production. Without visual input, increased joint flexion compensates for reduced ankle force exertion, leading to longer contact times. These findings suggest that while visual information blocking decreases SSC efficiency, explosive power can be maintained through biomechanical adjustments.
High-quality sports education has recently gained attention, boosting athletes' development and performance. Despite research on the impact of coaching input, training intensity, and team cohesion on performance across various sports disciplines, there is still a need for further investigation. This study investigated the impact of coaching feedback quality, training intensity, team cohesion, and motivation on athletes’ performance, with a focus on self-efficacy and coach-athlete interactions. The study also investigated whether and how these factors could enhance athletes' performance. Eight hundred twenty-five Chinese athletes from various sports were involved in this research. The relationships between the considered variables were examined using Structural Equation Modeling (SEM). The study employed descriptive and inferential statistics to investigate the impact of coaching assistance, training intensity, and other factors on athletes' performance. Players' satisfaction with coaching help, self-efficacy, motivation, training intensity, team cohesion, and coach-athlete relationships were found to be positively correlated. The data also demonstrated that high-quality coaching input improved team cohesion, athletes’ motivation, and performance. The study emphasizes the importance of effective coaching, suitable training intensity, and teamwork in teaching athletes these skills. Together with increasing self-efficacy and positive coach-athlete interactions, these factors would improve competitive performance
The present study aimed to investigate how hand use and the eye state affected handwriting performance. Twelve right-handed students (6 females and 6 males, aged 27.2 ± 2.4 years) completed handwriting tasks with both dominant and non-dominant hands under eyes-open and eyes-closed conditions. Handwriting tracing dynamics, handwriting quality, and legibility were measured, while electromyography signals were recorded bilaterally from the upper limb muscles. A two-way ANOVA revealed no significant interaction effects of hand use and the eye state on handwriting tracing dynamics or muscle activity. However, significant interaction effects were found for the number of intersection points (p = 0.034, ηp² = 0.129) and the legibility score (p = 0.004, ηp² = 0.205). Post hoc tests indicated greater handwriting accuracy degradation in the non-dominant hand under eyes-closed conditions, with significant differences in the number of intersection points (p = 0.016, d = 0.350) and the legibility score (p < 0.001, d = −0.130). To further explore relative differences between eyes-open and eyes-closed conditions, the ratio of change was calculated for each handwriting feature. The results showed a significantly greater change in the number of intersection points (p = 0.027, r = 0.639) and the legibility score (p = 0.012, r = −0.723) for the non-dominant hand compared with the dominant hand. These findings highlight distinct neural mechanisms underlying handwriting control, suggesting greater reliance of the non-dominant hand on visual feedback for handwriting accuracy. This study advances our understanding of motor skill learning and the acquisition of fine motor skills.
This study investigated the relationship between isometric pull forces measured during land-based simulations and propulsive forces generated in water during arm pulls and leg kicks in butterfly and freestyle swimming techniques. Thirty male competitive swimmers (age: 19.47 ± 2.35 years; FINA points: 626.57 ± 65.21; body height: 184.10 ± 5.14 cm; body mass: 70.61 ± 8.91 kg; training experience: 9.53 ± 2.00 years; BMI: 22.17 ± 2.03 kg/m²) volunteered to participate in the study. Isometric arm pull forces were measured on a swim bench (Vasa Swim Trainer), while aquatic forces were assessed using a custom-built tethered system to isolate kick, pull and full-stroke conditions. The results indicated that arm contribution to propulsion was 66.91% in butterfly and 69.03% in freestyle, while legs contributed 33.09% and 30.97%, respectively. Significant positive correlations (p < 0.05) were found between land-based and water-based force data and swimming performance. These findings suggest that such simulations can be useful for both short-term performance assessment and long-term training strategy development.
This study aimed to compare the effects of three distinct resistance training methods, i.e., complex strength training (CST), plyometric training with additional loading (PT), and eccentric training (ET), on lower-limb biomechanics in the sagittal plane and on performance during the first step after pushing off the starting block. This study assessed the effects of the training protocols on sprint acceleration performance and muscular explosiveness in sprinters over an 8-week intervention period. Twenty-four male sprinters, with personal best times ranging from 11.00 to 11.70 s, were randomly assigned to one of the three groups: CST, PT or ET. Each group completed an 8-week training intervention. Kinematic and kinetic data for the first step off the starting block were synchronously collected using an infrared motion-capture system and force plates. The results indicated that CST was more effective than both PT and ET in enhancing step frequency, peak ground reaction force, lower-limb joint torque, and joint stiffness during the first step in sprinters. Accordingly, CST interventions may be particularly beneficial for improving sprint starts. These findings highlight the need for further long-term intervention studies to explore this potential in greater depth.
This study examined acute responses of blood lactate concentration ([La]), the countermovement jump (CMJ) and the rating of perceived exertion (RPE) after performing flywheel exercise at different power-loss thresholds (10% vs. 15%). Fourteen senior male basketball players (mean ± SD; age: 24 ± 3 years; body height: 1.89 ± 0.06 m; body mass: 84.8 ± 10.1 kg) were recruited. Participants completed three sets with 2-min inter-set rest intervals using a squat flywheel device in counterbalanced and randomized order. [La] and the CMJ (jump height, peak force, and the reactive strength index modified (RSImod)) were assessed before and after the exercise protocol at 1-, 3-, 5-, 7-, and 9-min time points. The level of significance was set at 0.05. Very-large time effects were present on [La] (mmol·L−1), large-to-medium effects on jump height (cm), small-to-medium effects on peak force (N) and large effects on the RSImod (AU). There were differences between protocols only for [La] (medium effect). The 15% condition presented larger [La], greater jump height and RSImod reductions compared to the 10% condition. No differences were found for the rating of perceived exertion (AU), and delayed onset of muscle soreness (AU). In conclusion, high acute metabolic and neuromuscular stress was caused by both protocols, with greater detrimental effects following the 15% condition.
Golf courses often present sloped surfaces that require players to adjust their swing mechanics. Understanding these adaptations is important for optimizing performance and maintaining consistency. This research studied how low-handicap golfers adjusted their body when performing golf swings on flat, uphill, and downhill slopes. Sixteen right-handed male university golfers (mean age 21.4 ± 2.4 years; body height 177.7 ± 4.7 cm; body mass 80.4 ± 11.0 kg; handicap 3.6 ± 1.6) performed swings using a 7-iron to swing on flat (0°), uphill (+10°), and downhill (−10°) slopes. The golfers’ movements were recorded using an optical motion analysis system. Kinematic data were analyzed using one-dimensional statistical parametric mapping (SPM 1D) with one-way repeated measures ANOVA. Significant differences (p < 0.05) were found in lower-limb joint angles and upper body inclination across slope conditions, while no significant differences were found in clubhead speed or pelvis and thorax rotation velocity. The findings show how golfers adjusted their posture to compensate for the slope while maintaining clubhead speed despite these postural changes. Initially, golfers addressed the ball by shortening the upper-side leg and aligning the upper body parallel to the slope. During the downswing, they gradually shifted their upper-body inclination toward a more upright posture relative to the ground, with lower-limb adaptations differing between the uphill and downhill conditions. These adjustments serve as strategies to sustain clubhead speed and optimize performance during uphill and downhill swings.
This study investigated the effects of ankle bracing on proprioception, agility, and lower-extremity biomechanics in 12 professional male basketball players. Ankle proprioception was assessed using the joint position reproduction (JPR) test, and kinematic data were captured using a 3D wearable motion capture system (Xsens MVN Awinda) during the change of direction (COD) agility T-Test. Tests were performed under braced and non-braced conditions (W bracing and WO bracing conditions, respectively). No statistically significant differences were found in proprioceptive accuracy between conditions (p = 0.975 and p = 0.995 for performed vs. reference angle errors in WO bracing and W bracing conditions, respectively). Similarly, no significant differences were observed in average velocity or time during COD movements (p > 0.05). However, the brace significantly restricted ankle range of motion, with the absolute angular error (AAE) in internal/external rotation reaching 3.03. Knee kinematics showed increased flexion restriction (AAE = 4.86) and moderate changes in abduction/adduction (AAE = 1.36). At the hip, internal rotation increased under the braced condition, though differences were not statistically significant (AAE = 2.80). Despite these biomechanical alterations and a non-significant reduction in proprioceptive feedback, agility performance was maintained (p > 0.05). These results suggest that while ankle bracing alters joint kinematics and limits ROM—especially at the ankle and knee—it does not significantly compromise agility performance. Prolonged use, however, may increase reliance on external stabilization, emphasizing the need for concurrent proprioceptive training in injury prevention protocols.
CrossFit’s popularity has increased as an effective training program for physical fitness. The volume of published literature suggests a continuous effort to understand and optimize CrossFit training protocols. Therefore, this study aimed to analyze scientific literature findings related to CrossFit’s biomechanical and physiological demands via a systematic review. Systematic searches were conducted on PubMed, Web of Science, ScienceDirect, Scopus, and SciELO databases for articles reporting the effects of CrossFit training. Following the PRISMA guidelines, nineteen studies (n = 537 participants) examined the use of biomechanical and/or physiological variables in CrossFit performance. This review considered the one-repetition maximum, the countermovement jump, peak power, and movement technique as biomechanical variables most often used in literature. The physiological variables included blood lactate, maximal oxygen uptake, heart rate variability, and the rating of perceived exertion. These variables accurately measured strength, aerobic and anaerobic capacity, along with fatigue in training sessions and competitions. CrossFit training was shown to improve maximal oxygen uptake, muscle strength, hypertrophy, and muscular endurance while also inducing physiological stress. Strength and power variables correlated strongly with CrossFit performance, but movement technique and postural control also played significant roles. The combination of aerobic and anaerobic elements within CrossFit enhanced cardiovascular fitness and anaerobic capacity, reinforcing effectiveness when appropriately managed.
