Countermovement Jump Research Articles

Optimizing Muscle Performance in Young Soccer Players: Exploring the Impact of Resisted Sprint Training and Its Relationship with Distance Covered.

Speed training with resisted sprints has been shown to positively affect neuromuscular performance in soccer players. Various loads, ranging from 10% to 120% of body mass, have demonstrated performance improvements across the spectrum. However, the impact of sprint distance with optimal load on these adaptive responses has yet to be thoroughly described. To analyze the influence of sprint distance in resisted sprints on muscle performance in young soccer players. This quantitative study utilized a pre-post experimental design. The sample consisted of 24 young soccer players (15.3 ± 0.68 years; 61.4 ± 7.08 kg; 1.60 ± 0.06 m) randomized into three groups (10, 20, and 30 m) and subjected to 12 sessions of resisted sprint training over six weeks. The volume was homogenized across groups, with a total distance of 120 m for each. The intervention's effect was analyzed through performance in the isometric mid-thigh pull (IMTP), countermovement jump (CMJ), modified 505 agility test (505 m), and linear sprint tests. Differences were analyzed using a mixed ANOVA, incorporating a between-subjects factor (training group) and a within-subjects factor (pre- and post-intervention). Time-dependent differences were observed in all groups for peak force (PF) (p < 0.001; η2p = 0.62), time to PF (TPF) (p < 0.001; η2p = 0.53), impulse at 50 (p < 0.001; η2p = 0.57), 100 (p < 0.001; η2p = 0.60), and 200 ms (p < 0.001; η2p = 0.67) in IMTP; jump height by impulse-momentum (p < 0.001; η2p = 0.64), rate of force development (p = 0.04; η2p = 0.14), yielding impulse (p < 0.001; η2p = 0.49), and concentric impulse (p = 0.01; η2p = 0.19) in CMJ; time (p < 0.001; η2p = 0.46) in 505 m; and average speed in linear sprint (p = 0.003; η2p = 0.36), with moderate to large effect sizes, regardless of the distance covered. No differences were observed for the interaction between the time* and group or between groups. Performance improvements were independent of the sprint distance, with no differences between training groups. Distances between 10 and 30 m may enhance muscle performance in young soccer players.

Acute Effects of Foam Rolling and Stretching on Physical Performance and Self-Perceived Fatigue in Young Football Players.

Background/Objectives: The aim of this study was to examine the acute effects of foam rolling and traditional stretch treatments on physical performance and self-perceived fatigue in youth football players. Methods: The sample of participants consisted of 20 youth football players from the Serbia Under-17 league. Participants were randomly assigned to one of two groups, the Foam group (age: 16.6 ± 1.5 years) or the Stretch group (age: 16.9 ± 1.0 years), with each group consisting of 10 participants. The first measurement (I) was conducted before the match; then, the football players played the match, which was followed by the second measurement (II), and afterward, the groups performed their foam and stretch activities. The third measurement (III) was conducted 2 h after the recovery interventions, and the fourth measurement (IV) was conducted 24 h after the match. Players were tested for the following: linear sprints at 5 m, 10 m, and 20 m, squat jumps (SJs), countermovement jumps (CMJs), and arm-driven countermovement jumps (ACMJs). Participants also completed self-assessment questionnaires on fatigue (Hooper scales) and perceived exertion (Borg scales). Results: A 2 × 4 split-plot ANOVA revealed that there were no differences between the foam rolling and stretching treatments in any parameter of physical performance or self-perceived fatigue. However, a separate within-group analysis showed that the Foam group achieved significantly better sprint times in the third and fourth measurements (2 and 24 h post-match, respectively) compared to measurements taken immediately after the football match. Regarding self-perceived parameters, foam rolling reduced fatigue and stress at 2 and 24 h post-match. On the other hand, the stretching treatment only affected the stress parameter, which was reduced 24 h after the football match. Conclusions: These findings indicate that although there were no significant differences between treatments, foam rolling demonstrated certain advantages compared to stretching. Specifically, foam rolling may offer benefits in enhancing subjective recovery and reducing perceived exertion in young football players. However, these conclusions should be interpreted with caution, as the study was cross-sectional and involved a small sample of young football players.

The impact of fatigue on the jumping mechanics and injury risk of basketball players

Fatigue can significantly alter an athlete’s biomechanics and performance, which can increase their risk of injury. Important basketball moves like jump shots (JS) and countermovement jumps (CMJ) primarily use the muscles in the lower back and lower limbs. Basketball players’ jumping mechanics, performance, and risk of injury during CMJ, JS, and ankle sprains were all examined. A total of 415 male collegiate basketball players participated in the league, this season representing varying levels of jumping mechanics. Surface electromyography, a force plate, and a 3D motion analysis system were used to gather data. Field-goal percentage, the center of mass’s (CM) lowest point, joint angles during takeoff and landing, and Electromyography data from the lower leg muscles, erector spinae limbal, and rectus femoris were among the parameters that were recorded. Lower back muscle tiredness was created, and performance was evaluated after the fatigue. Data was analyzed using SPSS, with paired-sample t-tests, logistic, and Multiple Regression tests employed to examine the impact of fatigue on performance and injury risk. These tests assessed how fatigue affects shooting accuracy and joint angles, and increases the chance of injuries in basketball players. Following a period of tiredness, athletes’ field-goal percentages significantly decreased, whereas their CM lowest point increased on jump shots. In both CMJ and JS, fatigue leads to reduced knee flexion angles and increased ankle plantar flexion during landing, changing the contribution ratio of both legs. Due to impaired mechanics, these biomechanical changes suggest an increased probability of ankle sprains and an elevated risk of damage, especially during landing. The risk of lower back, knee, and ankle injuries increased due to major athletic impairments and altered landing mechanics caused by lower back muscular fatigue. To reduce basketball players’ risk of injury, these data highlight how crucial it is to address fatigue in training and recovery plans.

Specific Physical and Nutritional Preparation of a Professional Kata Karate Athlete: A Case Study with a Bronze Medallist from the Pan American Games.

In karate, particularly in the kata discipline, there is a notable lack of studies focused on specific physical preparation for competitions. This highlights an urgent need for more in-depth research into this crucial aspect of athletic training to optimize performance and athlete preparation. The objective of this study was to analyze the influence of a dietary plan combined with specific physical preparation on the performance and body composition of a professional kata athlete preparing for a Pan American championship. A 20-year-old elite female karateka (60.7 kg, 165.4 cm) followed a nutritional plan with an isocaloric diet. The strength and power of the upper and lower limbs were evaluated through countermovement jump (CMJ) and one-repetition maximum (1RM) tests in bench press and free squat over a five-month period before the competition. Following the nutritional plan and physical preparation, the athlete's body composition improved in terms of fat loss (from 12.17% to 10.68%) and increased muscle mass (from 51.45% to 53.09%). Moreover, these improvements translated into better performance in tests such as CMJ (from 38.29 cm to 44.14 cm), 1RM bench press (from 54.5 kg to 67.6 kg), and 1RM free squat (from 65.1 kg to 78.4 kg). This study demonstrates that a comprehensive approach to personalized physical, technical, and nutritional preparation over 16 weeks significantly improves muscle strength and performance in karate kata. The novelty of this intervention lies in the detailed description of the total workload, encompassing both physical and technical performance, with a specific plan tailored to the athlete's needs. Additionally, the preparation was precisely designed for a specific tournament, addressing the sport's unique demands.

Kinesio Taping does not Enhance Jump Performance and Muscle Activity in Female Athletes.

This study aimed to investigate the effect of Kinesio Taping (KT) application on the single-leg counter-movement jump (CMJ) and surface electromyographic (sEMG) activity in trained female athletes, in both resting and fatigued states. In this single-blind, randomized, sham-controlled trial, twenty-four healthy trained female athletes were randomly assigned to either the KT (n=12) or the sham tape group (n=12). KT was applied using an inhibition technique on rectus femoris, vastus medialis, biceps femoris, and lateral gastrocnemius muscles of the dominant leg. A single-leg CMJ test and sEMG activity were recorded at baseline (no tape), as well as at 1 hour, 24 hours, and 48 hours after taping. To induce acute neuromuscular fatigue, a 30-second repetitive CMJ test was used to evaluate KT in fatigued states. In the resting states, both groups exhibited improvements in jump height, power, mean velocity, and sEMG activity (%EMGmax) over time, with no significant between-group differences. The single-leg CMJ performance was similarly decreased after the muscle fatigue protocol in both groups, showing no between-group differences. Our findings suggest that KT treatment does not appear to influence jumping performance, sEMG activity, or muscle fatigue in female athletes.

Impact of Caffeine Intake on Female Basketball Players' Performance.

This study aimed to analyze the effect of caffeine ingestion on basketball performance in semi-professional female players. A double-blind, placebo-controlled, randomized experimental design was conducted, in two different periods separated by a week. Twelve female basketball players ingested 3 mg of caffeine/kg of body mass or a placebo. After 60 min, participants completed two repetitions of the specified sequence: Abalakov jump, countermovement jump (CMJ), 5-0-5 (505) test, and 20 m sprint. Later, external loads and game statistics were recorded during a 30-min simulated basketball game. Significant improvements were observed in CMJ height and 505 test with caffeine ingestion compared to the placebo. Significant moderate differences were evident between conditions in external load variables, specifically, an increased number of high-intensity changes of direction during simulated games with caffeine ingestion. Two-point shot efficiency significantly improved after pre-caffeine ingestion compared with placebo. Three mg of caffeine per kg of body mass may serve as an effective ergogenic aid to increase physical performance and some variables of performance index in highly trained basketball players.

Influence of the order of the physical qualities during the microcycle on the weekly external loads and match day's readiness level in highly trained academy soccer players.

Highly trained academy soccer practitioners usually implement an aerobic-oriented session followed by a speed-oriented session during the first and second heavy load session of a training week, respectively. This study aimed to investigate if the order of these physical training sessions would influence the external training loads and the subsequent readiness level on match day. Twenty-five highly trained academy soccer players (12 U17 and 13 U19) participated in two experimental weeks randomly presented. The AEROBIC-SPEED periodization implemented an aerobic-oriented session on MD-4 and a speed-oriented session on MD-2. The SPEED-AEROBIC periodization did the opposite. During these two sessions, players wore a global positioning system and rated their perceived exertion (RPE). Players were also tested on MD-4 for baseline values (CONTROL) and match-day (TEST). Tests included a counter movement jump (CMJ), a 20-m sprint, the Illinois agility test (IAT), and the Hooper questionnaire. For the aerobic-oriented session, players reported greater distances during AEROBIC-SPEED periodization than SPEED-AEROBIC in 15-20 km/h (1273.53±328.51 m vs. 1174.84±210.33 m, P<0.05) and 20-25 km/h (658.92±264.41 m vs. 478.17±259.10 m, P<0.01). For the speed-oriented session, players reported greater distances during SPEED-AEROBIC than AEROBIC-SPEED periodization in 20-25 km/h (298.84±120.12 m vs. 223.24±114.86 m, P<0.05) and >25 km/h (110.74±34.65 m vs. 84.96±43.85 m, P<0.05). Tests revealed similar values for CONTROL and TEST between the two experimental weeks for CMJ, 20m, IAT and Hooper. The physical qualities (both aerobic and speed), when periodized at the beginning of the week (on MD-4) rather than later (MD-2) showed higher external loads without changing the readiness level on MD. The results emphasize the need to periodize the training contents according to the aim of the cycle.

Concurrent Effects of Plyometric Interval Training Implemented in Physical Education Lessons on Adolescent Power and Endurance: An Analysis of Responder Prevalence.

Schools provide an ideal setting for enhancing adolescents' health and fitness. Short-term intensive interventions are particularly relevant, but the effectiveness of plyometric exercises in jointly improving aerobic and anaerobic performance remains uncertain. This study aimed to evaluate the effects of plyometric-based training, in the form of interval workouts during physical education lessons, on power and endurance in adolescents. A total of 87 boys and 95 girls (aged 14-15 years) participated in an 8-week intervention, performing plyometric exercises twice weekly during physical education classes. The analyzed parameters were jump height (JH) measured by countermovement jump (CMJ) and distance covered during multistage fitness test (MFT). The results showed significant improvements among boys participating in the JH experiment and the distance covered in the MFT (p < 0.05); thus, the effect sizes were relatively small (ES < 0.3). Also, the prevalence of positive responders was more common for boys than girls; however, the difference was statistically insignificant (p = 0.09). These findings suggest that plyometric training has the potential for improving physical fitness, even in the context of developing opposing physical abilities, particularly in boys. However, the effects varied across individuals and were generally small, highlighting the need to optimize the intervention to achieve more pronounced results tailored to individual characteristics.

Physiological Responses of Elite Cheerleaders During Training and Simulated Competition Routines.

Competitive cheerleading (cheersport) is a physically demanding sport; however, there is a lack of information regarding its acute physiological responses during training or competition in these athletes. Thus, this study aimed to investigate these responses during both training sessions and simulated cheerleading competition routines (full-outs) among elite cheersport athletes. Six Coed and 10 All Girl elite cheerleaders were included in this study. Countermovement-jump (CMJ) height and blood lactate concentration were measured prepractice, after warm-up, after a full-out, and at the end of the training session. Heart rate (HR) was monitored throughout all the sessions. One-way analysis of variance was used to analyze changes over time. Most of the training time (51%-68%) was spent between 50% and69% maximum HR. Only 3% to 4% was spent above 90% HRmax. During full-outs, most of the time (67%-80%), HR was ≥80% maximum HR. The blood lactate concentration was significantly elevated post-full-out (6.4 [1.6]mmol/L) compared with pretraining and post-warm-up (P < .001). In addition, blood lactate concentration was higher after training (3.4 [2.2]mmol/L) compared with prepractice and post-warm-up (P ≤ .025). CMJ height did not change over time (P ≤ .268). Cheersport training leads to a low overall metabolic demand but is interspersed with short, high-intensity "intervals." The highest intensities were achieved during full-outs, indicating the anaerobic nature of competition routines. Therefore, cheerleaders should train both the aerobic and the anaerobic systems to increase recovery capacity between drills and to maximize anaerobic power during competition.

Relationship between muscle power, muscle volume and limb length in healthy male and female adolescents.

Muscle power is essential for the activities of daily living. Muscle power production depends on numerous factors such as muscle size and length, muscle architecture and fiber type and varies with age during growth. The association between muscle power output during a jump and lower limb muscle volume and length in adolescents is largely unknown. This study determined the relationships between muscle power developed during a countermovement jump with lower limb muscle volume and length in adolescents aged between 16 and 19 years. Forty healthy adolescent males (n = 20) and females (n = 20) aged 16 to 19 years underwent a counter-movement jump (CMJ) test. Muscle power (MP) during the jump was calculated using the Gomez-Bruton equation. Lower limb muscle volume (MV) and length were calculated in both sexes using anthropometric methods. Pearson correlation was used to assess the associations between variables. Independent-sample t-tests were used to compare anthropometric and muscle performance data between males and females. Cohen's d was used to determine the size of the differences. There were differences in all anthropometric variables between males and females (p < 0.001). CMJ height (d = 4.45; p = 0.001) and MP (d = 4.74; p = 0.001) were greater in males than in females (p < 0.001). These differences persisted when jump performance was normalized to the MV (d = 1.05; p = 0.01) and length (d = 4.07; p = 0.001). There were correlations between MV and MP for males and females, with a significant correlation between limb length and MP for males (r = 0.55; p = 0.002). This study indicates that MV and length are associated with MP production during a CMJ in adolescents aged between 16 and 19 years, suggesting that these factors may be important determining factors for vertical jumping performance during adolescence. The sex-differences in jump performance variables persisted after normalization by MV and length, suggesting that MV and length did not entirely explain the sex difference in muscle power output during a CMJ.

Lower Extremity Stretch-Shortening Cycle Performance in the Vertical and Horizontal Direction as Key Determinants of Success in Collegiate Male Taekwondo.

The underlying mechanisms of taekwondo-specific jumping ability among different competition levels are still unknown. This study aimed to compare vertical and horizontal stretch-shortening cycle (SSC) performance between athletes of different competitive levels and examine the relationships of force and power production abilities between those two directions in Taiwanese collegiate-level male taekwondo athletes. Seventeen male collegiate taekwondo athletes were divided into two groups: medalists (MG, n = 8) and non-medalists (NMG, n = 9); both groups performed countermovement jumps (CMJ) on a force platform and single-leg lateral hops (SLLHs) via an optoelectronic measurement system. Eccentric and concentric phase measures from CMJ and distant and temporal variables of SLLH were collected for further analysis. The MG achieved statistically superior jump height (JH), concentric peak velocity, eccentric peak force, force at 0 velocity, and eccentric displacement than NMG (d = 1.05-1.36). Although non-significant differences showed in SLLH variables, MG had better results than NMG (d = 0.40-0.84). Moderate relationships were identified between SLLH step 1 and JH, reactive strength index modified, peak concentric power, and peak concentric velocity of CMJ (r = 0.50-0.57, p < 0.05). Furthermore, step 2 ground contact time and lateral reactive strength index from SLLH were associated with CMJ peak eccentric force, peak concentric force, and force at 0 velocity (r = 0.53-0.59, p < 0.05). Taekwondo MG achieved superior CMJ and SLLH performance. In addition, jumping abilities in vertical and lateral directions shared specific underlying mechanisms in collegiate male taekwondo athletes.

Carbohydrate Mouth Rinsing Improves Softball Launch Angle Consistency: A Double-Blind Crossover Study.

(1) Background: Carbohydrate mouth rinsing (CMR) stimulates the central nervous system and improves motor control. However, no studies have examined the effects of CMR on softball batting performance. The purpose of this study was to investigate the effect of CMR on softball batting performance. (2) Methods: Fifteen trained female collegiate softball players (age: 20.6 ± 0.9 years; height: 159.5 ± 5.2 cm; body weight: 58.1 ± 6.9 kg) completed two trials in a randomization crossover trail, in which they rinsed their mouths for 20 s with 25 mL of either 6.4% maltodextrin (CMR) or a placebo (PLA). After rinsing, the Posner cueing task and grip force, counter-movement jump (CMJ) and batting tests were performed in sequence. A tanner tee was utilized to hit five sets of five balls at a time, with a minimum 3 min rest between sets. The batting test recorded the average exit velocity, maximum exit velocity and launch angle consistency. The standardized standard deviation (SD) for launch angle represents the standardized variability. (3) Results: The consistency of the launch angle of the CMR trial was significantly greater (p = 0.025; Cohen's d = 0.69) than that of the PLA trial. There were no significant differences in the Posner cueing task, grip strength, vertical jump, or exit velocity. (4) Conclusions: The findings of this study indicate that CMR enhances the launch angle consistency of all-out-effort batting, but does not influence the exit velocity of softball hitting.

The Use of the Self-Selected Rest Interval Method Is as Effective for Optimizing Postactivation Performance Enhancement in Elite Athletes as Employing the Best Fixed Rest Interval.

Fontanetti, G, Barreto, RV, Junior, RC, Marangoni, V, Denadai, BS, Greco, CC, and Lima, LCR. The use of the self-selected rest interval method is as effective for optimizing postactivation performance enhancement in elite athletes as employing the best fixed rest interval. J Strength Cond Res 39(1): 10-15, 2025-This study investigated whether the adoption of a self-selected recovery interval (SSI) is more effective than the use of a fixed recovery interval (FRI) to elicit postactivation performance enhancement (PAPE). Ten male professional volleyball athletes (20.6 ± 1.5 years; 92.8 ± 4.9 kg; 195 ± 8 cm) participated in 3 experimental sessions, in random order, following familiarization with countermovement jump (CMJ) exercises and determination of the load for 5-repetition maximum (5RM: 146 ± 27 kg) squat exercise. The 3 experimental sessions consisted of (a) control session (CON), with measurement of CMJ height 4 minutes before and 2, 4, 6, 8, and 10 minutes after subjects rested while sitting in a chair without performing any preactivation (PA) protocol; (b) session with FRI, with measurement of CMJ height 2, 4, 6, 8, and 10 minutes after performing a PA exercise consisting of 5 squats with 5RM load; and (c) session with SSI, with evaluation of CMJ height once after performing the PA adopting a SSI based on a readiness scale. No significant differences were found between CMJ height in the CON session. Countermovement jump height was higher (p < 0.05) than the baseline measurement at minutes 4, 6, and 8 post-PA in the FRI session, for the best CMJ performance during the FRI session, and after the PA in the SSI session. No significant differences were found between the heights of the best CMJ in the FRI session (49.2 ± 6.8 cm) and post-PA in the SSI session (49.6 ± 6.6 cm). Therefore, adopting FRI and SSI is equally effective in eliciting PAPE in elite athletes. Despite being as effective as adopting FRI to elicit PAPE, SSI is more intuitive and easily applicable in contexts where PAPE can be implemented.

Neuromuscular Performance and the Intensity of External Training Load During the Preseason in National Collegiate Athletic Association Division I Men's Collegiate Basketball Players.

Curtis, M, Kupperman, N, Westbrook, J, Weltman, AL, Hart, J, and Hertel, J. Neuromuscular performance and the intensity of external training load during the preseason in National Collegiate Athletic Association Division I men's collegiate basketball players. J Strength Cond Res 39(1): 54-61, 2025-The aim of the study was to determine whether acute changes in neuromuscular performance can be detected through countermovement jumps (CMJs) conducted pre- and postpractice sessions in conditions of high or low intensity measured by microsensors technology. Using an observational repeated measures design, data were collected from 10 male collegiate basketball players. Countermovement jump data were collected before and after practice exposures over 4 weeks of preseason. Select CMJ kinetics were compared in conditions of high and low training load intensity to detect neuromuscular performance changes in displacement of the center of mass and kinetics. Kinetic measures were categorized as output, underpinning, and strategy-related variables. We investigated "output" defined as displacement (jump height [JH]), "underpinning" defined as force-related (mean eccentric force, mean concentric force, force at zero velocity), and "strategy" defined as time-related (countermovement depth [CMD], eccentric duration (EccDur), concentric duration [ConcDur]) variables. There were significant condition × time interactions in CMJ variables namely eccentric mean force (EccForce), force at zero velocity (Force@0), CMDepth, EccDur, and ConcDur. In conditions of high intensity, players had significant, but small decreases in EccForce and Force@0, with small increases in CMD, EccDur, and ConDur, respectively. However, there were no significant decreases in JH. High-intensity practice exposures did not impact neuromuscular performance specific to "output," suggesting that collegiate basketball athletes can maintain JH despite alterations in "underpinning" and "strategy-related" variables. This could have relevance in understanding how fatigue associated with higher-intensity training exposures may potentially alter jump strategy and force production capacities due to external load intensity in collegiate basketball athletes.

Effects of different pre-exercise strategies on jumping performance in female volleyball players.

The present study aimed to compare different pre-exercise strategies on jumping performance in female volleyball players. Fifteen healthy female volleyball players (age=18±0.6 years; training experience = 7.3±1.4 years; height = 164.8±5.4 cm; body mass = 57.2±8.1 kg) volunteered to participate in the study. Three different pre-exercise conditions (5 repetition maximum knee extension, electromyostimulation [EMS] and ischemic preconditioning [IPC]) were applied to the subjects and compared to a control condition performing a standardized warmup. Subjects performed the squat jump and 15 sec repeated countermovement jumps following a rest period. Measures associated with jumping performance were collected and compared between conditions. Rating of perceived exertion was also collected after each performance test. No pre-exercise condition outperformed a standardized warm-up on inducing improvements in jumping performance and in fact, EMS and IPC conditions resulted in performance decrements compared to control (P<0.05). We conclude that a standardized warm-up is enough to induce improvements in jumping performance in female volleyball players. Future research should examine alternative strategies alongside standardized warm-up to determine how best to prepare for jumping and related sport-specific tasks in female volleyball players.

Impact of Congested Match Schedules on Countermovement Jump Metrics in Elite Volleyball Players.

Rebelo, A, Loturco, I, Pereira, JR, Martinho, DV, Valente-dos-Santos, J, and Broek, GV. Impact of congested match schedules on countermovement jump metrics in elite volleyball players. J Strength Cond Res XX(X): 000-000, 2024-The aim of this study was to assess the impact of a congested match schedule on various countermovement jump (CMJ) metrics recorded across the braking, transfer, propulsive, and flight phases of the CMJ. Fourteen male elite volleyball players were monitored across 7 microcycles, with CMJ assessments conducted at 14 time points using portable force plates. Repeated measures analysis of variance with Bonferroni post hoc tests and coefficient of variation (CV) analysis were used to analyze the data. The CVs for all metrics indicated a moderate variability between microcycles and low variability between the beginning and end of the weeks. Significant variability was observed in key performance metrics, including peak propulsive power (p < 0.001, partial eta squared [ηp2] = 0.336), peak propulsive velocity (p = 0.005, ηp2 = 0.207), propulsive phase duration (p = 0.008, ηp2 = 0.197), and jump momentum (p = 0.019, ηp2 = 0.225), across microcycles. These findings indicate that these CMJ metrics may be used as sensitive indicators of fatigue and performance changes during intense training and competitive periods. The total score of athleticism, calculated by averaging a set of standardized scores from multiple tests or repeated measures of the same test, for the propulsive and flight phases, proved to be particularly useful in providing a comprehensive view of the neuromuscular status. This emphasizes the importance of recording and analyzing a range of CMJ metrics to optimize training and recovery strategies in elite volleyball players.

Acute Responses to Different Lifting Velocities During Squat Training With and Without Blood Flow Restriction.

Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Páez-Maldonado, J, Rodiles-Guerrero, L, Sánchez-Moreno, M, Gómez-Guerrero, G, León-Prados, JA, and Pareja-Blanco, F. Acute responses to different lifting velocities during squat training with and without blood flow restriction. J Strength Cond Res XX(X): 000-000, 2024-The aims of the research were to compare the acute mechanical, metabolic, neuromuscular, and muscle mechanical responses to different lifting velocities (maximal vs. half-maximal) under distinct blood flow conditions (free [FF] vs. restricted [BFR]) in full-squat (SQ). Twenty resistance-trained males performed 4 protocols that differed in the velocity at which loads were lifted (MaxV: maximal velocity vs. HalfV: half-maximal velocity) and in the blood flow condition (FF: free-flow vs. BFR: 50% of arterial occlusion pressure). The relative intensity (60% 1 repetition maximum), volume (3 sets of 8 repetitions), and resting time (2 minutes) were matched between protocols. Mean propulsive force (MPF), mean propulsive velocity (MPV), mean propulsive power (MPP), and electromyography (EMG) values were recorded for each repetition. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ), maximal voluntary isometric contraction in 90° SQ, and performance with the load that elicited a 1-m·s-1 velocity at baseline measurements (V1-load) in SQ were assessed at pre-exercise and postexercise. The MaxV protocols showed significantly greater MPF, MPV, MPP, and EMG amplitude during the exercise than the HalfV protocols (velocity effect, p < 0.05). The FF protocols achieved higher MPF and MPP during exercise than BFR (BFR effect, p < 0.05). The BFR protocols induced greater blood lactate after exercise (BFR × time interaction, p = 0.02), along with higher postexercise impairments in mechanical performance (BFR × time interaction, p < 0.05). The MaxV protocols elicited superior performance and greater muscle activation during exercise. The BFR protocols resulted in lower force and power production during exercise and exhibited higher performance impairments and increased metabolic stress postexercise.

Pes Planus Level and Foot Pain Affect Selected Performance Parameters: A Study on Team Sport Athletes

Aims to investigate the relationship between pes planus (PP) with foot pain (FP) and performance in team sport athletes. Correlational research was adopted to reveal the relationship between PP with FP and performance. There were 84 athletes were involved in this research. Measurement of PP with footprint test (FT), FP with knee pain intensity-visual analogue scale (KPI-VAS) and performance with items 30m sprint (30ms), modified agility t-test (MATT), counter movement jump (CMJ), standing stock balance test (SSBT). We observed that FT-PP variable has a moderate negative correlation with FP-KPI-VAS (p = 0.003), which shows that PP significantly causes foot pain. In CMJ (p = 0.035) and SSBT (p = 0.004) there is a moderate negative correlation, which shows that the PP level reduced the level of power and balance. Meanwhile, there is a moderate positive correlation with 30mS (p &lt; .001), and MATT (p &lt; .001), which shows that the level of PP will reduce the level of running speed and agility. At the same time, FP-KPI-VAS had a small negative correlation with 30mS (p = 0.017), MATT (p = 0.017) and CMJ (p = 0.048). Finally, FP-KPI-VAS was found to have a large positive correlation with SSBT (p &lt; .001). Thus, we confirm that PP is significantly correlated with FP and performance related to 30ms, MATT, CMJ, SSBT in team sports athletes.

Validity of the Enode Sensor and My Jump 3 App for Assessing Countermovement Jump Performance

Countermovement jump (CMJ) performance analysis is vital in sports science for assessing lower-body strength and neuromuscular efficiency. This study evaluated the validity of the Enode Sensor and My Jump 3 App for measuring vertical jump heights, comparing them to those measured using the established Force Plate. Twenty-nine participants performed CMJs measured using each device. Descriptive statistics indicated mean jump heights of 48.4 ± 4.18 cm (for the Enode Sensor), 47.3 ± 4.05 cm (for My Jump 3), and 46.1 ± 4.03 cm (for the Force Plate). Reliability was confirmed via Intraclass Correlation Coefficients (ICCs), with the Enode Sensor at 0.914 and My Jump 3 at 0.968, demonstrating excellent reliability. Bland–Altman analysis showed mean biases of 2.281 cm (for the Enode Sensor) and 1.297 cm (for My Jump 3) against the Force Plate, with limits of agreement suggesting close alignment. Strong positive correlations were observed (for the Enode Sensor, r = 0.972 and for My Jump 3, r = 0.987; p &lt; 0.001), and linear regression analysis produced R2 values of 0.945 and 0.973, respectively, confirming both tools’ accuracy for vertical jump measurement. These findings indicate that although both tools are suitable for CMJ assessment, My Jump 3 demonstrated slightly superior accuracy, underscoring the potential for accessible, reliable performance monitoring in sports contexts.

Short Term Effects of Proprioceptive Neuromuscular Facilitation Combined with Neuromuscular Electrical Stimulation in Youth Basketball Players: A Randomized Controlled Trial.

Background: Hamstring muscle injuries are common in basketball and result in long periods of inactivity. To reduce their incidence, preventive protocols, including proprioceptive neuromuscular facilitation (PNF) stretches, have been proposed. The aim of this study is to compare the short-term effects of PNF and PNF + neuromuscular electrical stimulation (NMES) on hamstring extensibility and, secondarily, on vertical jump capacity in young basketball players. Materials and Methods: The study was a randomized controlled trial. One group performed a PNF stretching protocol and the other PNF + NMES. Hamstring extensibility was measured using the Sit and Reach test and the popliteal angle and jump capacity were measured using the Counter Movement Jump, both before and immediately after the intervention. Results: Forty-five young male players participated. Both groups showed significant intra-group improvements (p < 0.001) in hamstring flexibility after the intervention. However, there were no significant intra-group differences (p > 0.05) in jump capacity. Additionally, no significant differences (p > 0.05) were observed between the two groups for any of the measured variables. Conclusions: Both programs are effective in increasing hamstring flexibility in the short term without impairing vertical jump capacity in young basketball players.