Countermovement Jump Height Research Articles

The Effects of Inter-Limb Asymmetry on Change of Direction Performance: A Systematic Review

Objectives: This review aimed to clarify the associations between COD performance and asymmetries on horizontal jumping, vertical jumping, and strength. Methods: Three databases, including PubMed, Web of Science, and MEDLINE(EBSCOhost) were used to perform a systematic literature search. The search was up to 13 March 2022 and was limited to the literature in the English language and on the human species. Studies included reported exact measurement tools and correlation coefficients and studies in which participants aged >14 years were included. Moreover, studies that were not peer-reviewed and those that did not report an asymmetry index were excluded, as were studies for which the full text was not available. The modified Downs and Black Quality Index tool was used to evaluate the quality of the studies. Results: The systematic literature identified 1151 studies, but only 12 studies were included in this review. A total of 354 participants, ranging from 15 to 23 years of age, were recruited for these studies. The methodological quality score ranged from 6 to 8, with an average of 7.25. The associations between COD performance and vertical jump height, horizontal jump distance, and lower-limb strength asymmetries were examined in 11, 5, and 2 studies, respectively. Six studies reported that vertical jump height asymmetries scores can significantly reduce COD performance, while significant associations between COD performance and horizontal jump distance asymmetries and strength asymmetries were only observed in one study each. Specifically, four studies explored the relationships between CMJ height asymmetries scores and COD performance, and all reported significant associations between them. The main limitations of this review were that it did not consider the sports in which the participants were involved. Conclusions: This study suggests that drop jump height and eccentric knee strength asymmetries can reduce COD performance. Moreover, low horizontal jump asymmetries may not influence COD performance. Further research needs to determine whether the minimal threshold of horizontal jump asymmetries would not affect COD performance.

Post-Isometric Back Squat Performance Enhancement of Squat and Countermovement Jump.

The effectiveness of isometric conditioning activity (CA) is not well described in terms of the level of performance enhancement and the presence of a stretch and shortening cycle in subsequent explosive tasks. Therefore, the aim of this study was to evaluate the effect of a maximum isometric squat as the CA and a subsequent squat jump (SJ) and countermovement jump (CMJ) height. A total of 31 semi-professional handball and soccer players were randomly assigned to two different conditions: (i) 3 sets of 3 repetitions (each lasting 3 s) of maximum isometric back squats (EXP), and (ii) no CA (CTRL). The jump height measurements were performed 5 min before the CA and approximately at the 4th and 8th minute following the completion of the CA. Due to the high inter-individual variability in the potentiation responses, the best value obtained post-CA was also analyzed. The SJ height significantly increased from baseline to the 8th minute post-CA (p = 0.004; ES = 0.31; Δ = +3.1 ± 5.0%) in the EXP condition. On the other hand, the CMJ height was significantly higher in the 4th (p = 0.001; ES = 0.23; Δ = +2.7 ± 3.7%) and 8th minute post-CA (p = 0.005; ES = 0.32; Δ = +3.6 ± 5.7%) in comparison to baseline during the EXP condition. Furthermore, SJ height significantly increased from baseline to the best time-point during the EXP (p < 0.001; ES = 0.47; Δ = +4.9 ± 4.9%) and CTRL (p = 0.038; ES = 0.21; Δ = +2.5 ± 5.8%) condition. Moreover, the CMJ height was significantly higher at the best time-points than at the baseline during EXP (p < 0.001; ES = 0.53; Δ = +5.6 ± 4.7%) and CTRL (p = 0.002; ES = 0.38; Δ = +3.1 ± 5.2%) condition. The findings from this study indicate that a maximum isometric squat, used as a CA, effectively improved SJ and CMJ height. This suggests that the presence or absence of a stretch and shortening cycle in both CA and post-CA tasks does not significantly impact the post-activation performance enhancement response.

Impact of maximal strength training on countermovement jump phase characteristics in athletes with cerebral palsy

ABSTRACT Analysis of the countermovement jump (CMJ) force–time curve phases provides insight into athlete neuromuscular function and methods by which jump height improves in response to training. A CMJ phase analysis and the dynamic strength index (DSI) have yet to be explored in athletes with cerebral palsy (CP). This study aimed to address this knowledge gap. Eleven state- to international-level athletes with CP completed a pre-post maximal strength training intervention with waitlist control. CMJ was assessed via force plate pre/post baseline and after the 12-week intervention. Following the intervention, CMJ height, takeoff velocity, and concentric phase peak and mean force, impulse and mean acceleration improved significantly (p = 0.006–0.001). No changes were observed in any eccentric braking phase variable (p = 0.79–0.13), while DSI lowered (p = 0.03). In athletes with CP, strength training increased CMJ concentric phase peak and mean force and impulse, increasing velocity and acceleration and therefore jump height. DSI lowered due to moderate and small increases in isometric mid-thigh pull and CMJ peak force, respectively. Unlike in non-disabled athletes, strength training did not alter any eccentric phase variable; therefore, other modalities may be required to further optimize jumping performance in athletes with CP.

Relationship between neuromuscular profile and total volume of resisted sprint training in male professional soccer players

PurposeThis 11-week study aimed to correlate the neuromuscular profile and the total volume of resisted sprint training (RST) under different velocity loss (VL) magnitudes in male professional soccer players.MethodsSeventeen soccer players (age 25.8 ± 4.3 years; height 180.0 ± 8.6 cm; weight 77.7 ± 9.7 kg) were randomly allocated into two training groups, who trained at distinct percentages of VL: 10% of VL (G10, n = 8) or 20% of VL (G20, n = 9). The velocity-based sled training consisted of 20 m resisted sprints executed with a progressive loading increase (45–65% of body-mass). Sprint times (10 m and 20 m), vertical jump height [countermovement jump (CMJ) and squat jump (SJ)], knee flexion and extension peak torque, as well as isometric rate of torque development, and lower limb lean mass were correlated with the total volume of RST performed by G10 and G20 groups.ResultsThe G10 performed 31% less repetitions and total RST distance than G20 (p = 0.002). Significant negative Pearson’s correlations (large-to-very large) were observed between total volume performed by G10 and CMJ height [r = − 0.85, confidence interval at 95% (95% CI) = − 0.98 to − 0.58, p = 0.02, Cohen’s D effect size (ES) = 0.41] as well as SJ height (r = − 0.90, 95% CI − 0.99 to − 0.66, p = 0.005, ES = 0.80), and knee extension concentric peak torque (r = − 0.69, 95% CI − 0.99 0.91, p = 0.05, ES = 0.03). No further correlation was found (p > 0.05).ConclusionsWhen lower magnitudes of VL were used during training sessions (10%), the stronger and more powerful players performed lower volume of RST. Interestingly, this relationship is not confirmed when higher magnitudes of VL (20%) are prescribed (greater fatigue incidence).

Do Primary School Children Benefit from Drop-Jump Training with Different Schedules of Augmented Feedback about the Jump Height?

In children, the training of jumps leads to improved jumping and running performance. Augmented feedback about the jump height is known to facilitate performance improvements in adults. In the present study, the impact of augmented feedback on jumping performance was investigated in 4th grade primary school children executing drop-jump training for 8 weeks (24 sessions, 3 times/week). Ten children (eight males, two females, aged 9.6 ± 0.3 years), received feedback for 8 weeks, and 11 children (nine males, two females, aged 9.5 ± 0.2 years) received feedback only during the last 4 weeks. Drop-jumps training was integrated in physical education classes. Drop-jump and countermovement-jump heights were improved after 24 training sessions (p < 0.01 for both types of jumps in both groups). Ground contact times of drop-jumps were quite long (>200 ms) and not altered by training, and the reactive strength index of drop-jumps was between 0.75 and 1.5 in most children. Augmented feedback did not facilitate jumping performance like in previous studies with adult participants. In contrast, withholding augmented feedback during the first 4 weeks of training was associated with a reduction in jumping performance (p < 0.01 for drop-jumps, p < 0.05 for countermovement-jumps). Finally, improvements did not transfer to functional motor tasks containing jumps. According to the costs and outcomes we do not recommend drop-jump training with augmented feedback about the jump height for 4th grade physical education classes.

The Effect Of Cluster-sets Resistance Priming Training On Delayed Potentiation Of Athletes

Cluster sets (CS) resistance training can induce greater post-activation potentiation (PAP) effects than traditional sets (TS) by reducing fatigue. The neuromuscular performance response demonstrated in delayed potentiation (DLP) effects is similar to that in PAP, they are all based on the relationship between potentiation and fatigue. However, it is not clear whether CS resistance training can induce greater DLP effects. OBJECTIVE The aim of the study was to compare the delayed potentiation (DLP) effects induced by cluster sets (CS) versus traditional sets (TS) resistance priming (RP) training. METHODS Sixteen male collegiate athletes were recruited for the study in a crossover design. All the subjects performed a CS (30s interval between reps, 4 minutes interval between sets) and a TS (no rest between reps, 4 minutes interval between sets) RP training sessions (3 sets of 3 repetitions of barbell back squat at 85%1RM) in random order separated by 72 hours. countermovement jump (CMJ),20-meters sprint, and T-test were evaluated at baseline and 6 hours after the RP training sessions. RESULTS 6 hours after the RP sessions, both the CS and TS significantly improved the CMJ height (CS: 50.44 ± 8.35 cm, ES = 0.48; TS: 48.35 ± 8.05 cm, ES = 0.23), CMJ take-off velocity (CS: 3.21 ± 0.28 m/s, ES = 0.56; TS: 3.16 ± 0.27 m/s, ES = 0.38), CMJ push-off impulse (CS: 237.3 ± 26.99Ns, ES = 0.38; TS: 233.8 ± 24.96Ns, ES = 0.26), 20-meters sprint (CS: 2.967 ± 0.139 s, ES = 0.85; TS: 3.007 ± 0.122 s, ES = 0.58) and T-test (CS:9.805 ± 0.535 s, ES = 0.99; TS: 9.921 ± 0.64 s, ES = 0.73) performance compared with baseline values. The CMJ peak power (64.42 ± 8.92 W/kg, ES = 0.3) were significant better following the CS compared with baseline values. The CMJ height (ES = 0.25), CMJ peak power (ES = 0.2), 20-meters sprint (ES = 0.31) were significant better following the CS compared with the TS training session. No inter-condition significant difference was observed in CMJ take-off velocity (ES = 0.18), CMJ push-off impulse (ES = 0.13), and T-test (ES = 0.2). CONCLUSIONS Compared with TS, CS RP training resulted in greater DLP effects after 6 hours, and significantly improving athletes’ lower limb speed performance and power output.

Influence of the sport specific training background on the symmetry of the single legged vertical counter movement jump among female ballet dancers and volleyball players

IntroductionVertical jumps are the key components of performance in the classical ballet and volleyball. Asymmetry of performance between the lower extremities is a potential risk factor for injury. PurposeThe purpose of this study was to analyse the symmetry of the unilateral vertical countermovement jump (CMJ) in a group of female ballet dancers and in a group of female college volleyball players. MethodsWe tested the CMJ with the dominant and nondominant leg and the bilateral CMJ among 15 female ballet dancers and 15 female volleyball players aged 18–24 years. Ground reaction forces were recorded with the force plate and five variables were analysed - jump height, power, energy, and time to flight and time to maximum force during landing. Results2 × 2 repeated measures of ANOVA indicates that type of sport is influencing some of the single leg CMJ variables (energy used and time to maximal force in landing), there was a significant asymmetry between dominant and non-dominant leg in some of the vertical CMJ variables (CMJ height, energy used and the average power was marginally significant). The interaction between the type of sport and leg dominance however was not significant for all of the analysed CMJ variables indicating no difference in asymmetry between the dominant and non-dominant leg in the two investigated sports. The results expressed in the percentage differences between both legs that is widely used in the scientific literature showed that ballet dancers exhibited more symmetrical CMJ height, power, and energy compared to volleyball players. The average percent difference in CMJ height between the dominant and non-dominant leg was 4.26 (10.60) % and 13.36 (14.72) %, respectively. On average, volleyball players jumped slightly higher at the bilateral CMJ (p < 0.001). ConclusionSport-specific training background could explain the observed contralateral deficit differences between two sport groups. The elements of ballet training could be introduced into the volleyball training to overcome observed this contralateral deficit.

Utilizing Countermovement Jumps As A Measure Of Match Preparedness In NCAA Division I Women’s Soccer

PURPOSE: Training load quantification and monitoring is used in collegiate athletics to help coaches and supporting staff to determine whether players are prepared for upcoming matches. The purpose of this study was to assess the within-subjects correlation of matchday countermovement jump (CMJ) height and the 7-day sum of training load variables preceding matchday in NCAA Division I women’s soccer athletes. The authors hypothesized that matchday CMJ height would show negative moderate correlations with the 7-day sum of training load variables. METHODS: A total of 23 female soccer players (20 ± 1.1 years; 1.70 ± 0.07 m; 64.6 ± 7.0 kg) participated in this study. Data from seven matches from the 2020 season were included in this analysis. Repeated measures correlations (rmcorr) were used to determine the within-subjects correlations of matchday CMJ height and total distance covered (TD), training load score (TLS; using training impulse [TRIMP] calculations), number of sprints, and distanced covered at high-speed (< 9.32 mph; HODO). Alpha was set a priori at p ≤ 0.05 and the data was analyzed using R Studio (version 1.4.1106, R Studio, Boston, MA, USA) executing R (version 4.0.4, University of California, Berkeley, CA, USA). RESULTS: The correlations between training load variables and matchday CMJ height were not statistically significant (p > 0.05). The matchday CMJ height showed very weak nonsignificant relationships with TD (r = -0.071, p = 0.450, 95% CI = -0.254, 0.116), TLS (r = -0.016, p = 0.874, 95% CI = -0.191, 0.223), number of sprints (r = -0.116, p = 0.218, 95% CI = -0.296, 0.071), and HODO (r = -0.011, p = 0.904, 95% CI = -0.175, 0.197). CONCLUSIONS: The results suggest that the CMJ height may not be a good indicator of matchday preparedness in collegiate Division I women’s soccer as it did not correlate with the 7-day sum of training load variables preceding matchday. Future research should aim to address other strategies to assess matchday preparedness in collegiate women’s soccer in order to enhance training periodization to better prepare the athletes for competition.

A Physiological Profile Of Male And Female Division I Collegiate Tennis Players

Tennis requires high levels of reaction time, muscular power, and aerobic capacity. Assessments of these physiological parameters can aid in making decisions on training priorities, adaptations, and overall readiness. PURPOSE: The purpose of this analysis was to evaluate physiological and performance characteristics of male and female tennis players and identify relationships between metrics. METHODS: Collegiate tennis players (male [M]: n = 7, age = 20.7 ± 1.3 y, height = 186 ± 4 cm, body mass = 82.2 ± 4.5 kg; female [F]: n = 10, age = 19.6 ± 1.3 y, height = 166 ± 5 cm, mass = 65.3 ± 9.2 kg) participated in preseason testing to assess body composition, reaction time, muscular power, and aerobic capacity. First, body composition (body fat percentage [%BF], fat-free mass [FFM]) was measured by air-displacement plethysmography (BODPOD), followed by simple (Dynavision D2) and whole-body dynamic (Trazer) reaction time (RT), muscular power via maximal countermovement vertical jump with hands on hips (CMJ), and aerobic capacity (VO2max) via maximal graded exercise testing. Descriptive statistics are presented as mean ± standard deviation, and relationships between metrics were assessed using Pearson’s correlations (r) with an alpha-level of 0.05. RESULTS: Average %BF and FFM were 10.8 ± 4.0% and 73.3 ± 3.6 kg for M and 21.6 ± 6.2% and 51.7 ± 6.7 kg for F. Simple RT was 0.7 ± 0.1 s for both M and F, and dynamic RT was 0.5 ± 0.0 s for M and F. CMJ height was 56.4 ± 6.2 cm for M and 41.9 ± 4.4 cm for F. VO2max was 57.1 ± 5.1 mL/kg/min for M and 47.3 ± 5.8 mL/kg/min for F. %BF was inversely related to both CMJ (r = -0.72; P < 0.01) and VO2max (r = -0.77; P < 0.01). CONCLUSIONS: Overall, this sample was relatively lean, though M met the “Good-Excellent” category while F met the “Fair” category according to ACSM standards. Both measures of RT were consistent across M and F, though M had higher CMJ. VO2max was also higher in M, but both teams were considered “Excellent.” Correlational findings suggest increased BF% may negatively impact both anaerobic and aerobic performance, as athletes with higher BF% had lower CMJ heights and cardiovascular fitness. Future research should assess how these measures, particularly reaction time metrics, relate to on-court tennis performance.

Relationships between Functional Movement Quality and Sprint and Jump Performance in Female Youth Soccer Athletes of Team China.

This study aimed to determine the optimal functional movement screen (FMS) cut score for assessing the risk of sport injury, and to investigate the correlations between functional movement quality and sprint and jump performance. Twenty-four (N = 24) athletes performed all tests in one day at 10–30 min intervals, and the FMS test was performed first, without a warm-up session. After a standard warm-up, athletes then completed the Y-balance Test (YBT), sprint, counter-movement jump (CMJ), and standing long jump (SLJ), in turn. For each test, the best of three attempts was recorded for further analysis. A receiver operating characteristic (ROC) curve and area-under-the-curve (AUC) were used to determine the optimal FMS cut score for assessing the risk of sport injuries, and Spearman’s rank correlation analysis was used to quantify associations between functional movement scores and athletic performance. The average FMS score was 16.2 and the optimal FMS cut score for assessing the risk of sport injuries was 14.5. There were moderate relationships between total FMS score and 10–20 m sprint time (r = −0.46, p < 0.05), between In-line Lunge and 0–20 m sprint time (r = −0.47, p < 0.05), between Shoulder Mobility and 0–10 m sprint time (r = −0.48, p < 0.05), and between Trunk-stability Push-up and 10–20 m sprint time (r = −0.47, p < 0.05). Moreover, Hurdle Step score was largely correlated with 0–10 m time (r = −0.51, p < 0.05). For Y-balance, moderate correlations were observed between CMJ height and anterior asymmetry score (r = −0.47, p < 0.05) and posteromedial asymmetry score (r = −0.44, p < 0.05). However, there were no significant associations between YBT performance (asymmetric in three directions and composite score) and sprint performance (p > 0.05). Taken together, the results indicate that a FMS score of 14 is not a gold standard for assessing the risk of injury in all populations; we recommend that the FMS cut score of 14.5 should be the optimal score for assessing risk of injury in young female elite soccer players. Moreover, the FMS and YBT were introduced to assess the quality of functional movements, and they cannot be used to assess sprint and jump performance. Practitioners can use components of the FMS that have similar characteristics to specific sports to assess athletic performance.

Stable vs. variable eccentric load. Do they induce different training and physical performance outcomes?

ABSTRACT Since most movements on the field require athletes to produce forces in variable and unpredictable contexts, the use of training programs based on identical repetitions of an exercise may not be optimal for movement transference. Therefore, the aim of this study was to analyse the effects of unexpected eccentric load variability during resistance training in team sport players. Sixty-three men were randomly allocated to two experimental groups (Variable (VTG) and stable (STG) training group) and control group: (CG) volunteered to participate in this study. Experimental groups trained with the same average load of half-squat exercise twice a week for six weeks using rotary inertial devices (RIDs) with (VTG) and without (STG) an unexpected variability of the load. The squat force was measured for every session with force plates. Counter-movement jump (CMJ), sprint, and change of direction performances were measured pre and post-test. CMJ performance improved for VTG (p = .014; ES = 0.7) and STG (p = .005; ES = 0.79) but not for CG. Exposure to high eccentric forces with RIDs lead athletes to improve physical performance in the trained force vector but, since RIDs induce in high levels of variability per se, increasing the level of variability of the exercise will not add benefits to physical performance and training outcomes. HIGHLIGHTS The relevance of the study is to analyse if increasing the variability of the load will improve the athlete output to different physical performance tests. The exposure to eccentric overload with RIDs during the squat exercise allows to greater CMJ height improvements than those seen in the literature with RIDs without overloading the eccentric contraction. RIDs induce in high level of variability per se. Therefore, increasing the level of variability of the exercise will not add benefits to physical performance and training outcomes.

Contribution of Strength, Speed and Power Characteristics to Change of Direction Performance in Male Basketball Players

This study aimed to investigate the relationships between the modified t−agility test (MAT) time and muscular strength and power of lower limb extensors, adductors (AD), and abductors (AB). Nineteen male basketball players performed: linear sprint tests at 5 m and 20 m, MAT, countermovement (CMJ) and drop jump (DJ), leg press exercise, AD and AB hip maximum isometric strength measurements. All of them were left leg dominant. The correlation analysis showed a significant, moderate to very large negative relationship between MAT test time initiated to the left and height of CMJ and DJ (r = −0.69 and −0.54; p &lt; 0.01, both), left (r = −0.56; p &lt; 0.01) and right leg (r = −0.41; p &lt; 0.05) AD, left leg AB (r = −0.48; p &lt; 0.05) maximum isometric strength, left (r = −0.72; p &lt; 0.01) and right (r = −0.64; p &lt; 0.01) leg power output in leg press. In the case of the MAT test initiated on the right side first, the correlations were found between CMJ height (r = −0.46; p &lt; 0.05), AD and AB maximum isometric strength of left (r = −0.58 and −0.84; p &lt; 0.01, both) and right leg (r = −0.58 and −0.79; p &lt; 0.01, both), and both legs power output in leg press (r = −0.66 for left and r = −0.59 for right; p &lt; 0.01, both). The regression analyses showed that the prediction model of left leg press peak power, left leg AD maximum isometric strength, and CMJ height could explain up to 93% of the MAT test time initiated to the left first. The model, including left leg AB and AD maximum isometric strength, could explain up to 83% of the MAT test time initiated to the right side first. Findings from this study demonstrate that AB and AD maximum isometric muscle strength are highly related to MAT test performance, which is particularly important when the first turn is performed in the non−dominant direction in this test.

Association between Phase Angle from Bioelectric Impedance and Muscular Strength and Power in Physically Active Adults.

Simple SummaryThis study compared muscle strength and power indicators in resistance-trained men by evaluating associations between phase angle and performance, while controlling for body composition. We evaluated dynamic muscle strength in bench press and back squat, and muscle power using the Wingate test and countermovement jump. Participants with higher phase angle displayed superior muscle strength of the upper limbs and greater muscle power of the lower limbs. Regarding countermovement jump and bench press, phase angle showed moderate association with performance, even after controlling for body composition. Still, lean soft tissue was the most important predictor of muscle strength and power.This study aimed to compare muscle strength and power indicators according to bioimpedance spectroscopy’s phase angle (PhA) values, in resistance-trained (RT) men, while exploring associations between PhA and performance. Forty-four men aged 18–45 years, engaged in RT, were allocated according to PhA tertiles. Lean soft tissue (LST) and fat mass (%FM) were assessed using dual-energy x-ray absorptiometry; dynamic muscle strength using 1 repetition maximum (1RM) of bench press (BP) and back squat (BS) and muscle power using Wingate test (WT) and countermovement jump (CMJ). For WT and CMJ, the 3rd tertile was significantly higher than the 1st tertile (p = 0.027 and p = 0.018, respectively). Regarding BP 1RM, the 3rd tertile was significantly higher than the 2nd tertile (p = 0.037). LST better explained the variability in the WT, BS and BP (p =< 0.001), while %FM better accounted for jump height in CMJ (p =< 0.001). PhA was a predictor of performance in both CMJ (p = 0.040) and BP (p = 0.012), independently of LST and %FM. Participants with higher PhA also displayed superior muscle strength of the upper limbs and greater muscle power of the lower limbs. PhA displayed significant moderate associations with performance in CMJ and BP, even after controlling for body composition. Still, LST was the most important predictor of muscle strength and power.

Monitoring the post-match neuromuscular fatigue of young Turkish football players

Neuromuscular fatigue tests have been used in previous studies to organize post-match training programs and to minimize injuries. The aim of this study is to describe the neuromuscular fatigue that occurs after a football match and to examine the relationship between internal and external load values in the match and fatigue parameters obtained at different time intervals. Twenty male U19 academy league soccer players (age: 19; height: 181.3 ± 4.3; weight: 73.4 ± 6.7) participated in the study. The countermovement jump (CMJ) test was applied to the players 24 h before, as well as 24, 48, 72, 96, and 120 h after a football match. During the CMJ tests, the maximum velocity of each player during the jump was recorded by using the GymAware linear position transducer. The CMJ maximum velocity values 24 h before and 24 h after the match, as well as the CMJ height values (Cohen’s d: 1.210; p < 0.001), were statistically different from the values recorded 24 h before and 24 and 48 h after the match (Cohen’s d: 1.578; p < 0.001; Cohen’s d: 0,922; p < 0.009). The correlation values were not statistically significant. The results suggest, CMJ height and CMJ maximum velocity values, which determine neuromuscular fatigue after a football match, can be used by practitioners to display post-match neuromuscular fatigue measurements.

Differences in Rate of Force Development, Muscle Morphology and Maximum Strength between Weightlifters and Track and Field Throwers

The purpose of this study was to investigate the differences between weightlifters and track and field throwers in terms of the rate of force development (RFD), lean mass, muscle architecture and one-repetition maximum (1-RM) muscle strength. Sixteen elite male athletes (eight weightlifters and eight track and field throwers) participated in the study. Measurements were performed one week after the annual national championships and included anthropometry, body composition analysis (dual X-ray absorptiometry), vastus lateralis (VL) muscle architecture (ultrasonography), countermovement jump (CMJ), leg press isometric RFD and 1-RM strength in snatch and back squat. RFD was similar between groups (p &gt; 0.05), although RFD relative to lean mass was higher for weightlifters (p &lt; 0.05). Throwers had a higher trunk lean mass compared to weightlifters (p = 0.007). Weightlifters had a longer VL fascicle length compared to throwers (p = 0.037). Performances in CMJ height, CMJ power relative to body mass and 1-RM strength were higher for the weightlifters (p &lt; 0.05). Lean body mass index was correlated with back squat (r = 0.667) and snatch (r = 0.498). VL fascicle length was significantly correlated with snatch (r = 0.631) and back squat (r = 0.718). These results suggest that weightlifters may produce greater power outputs and 1-RM strength than track and field throwers, which may be associated with longer VL fascicle length.

The relationship between external and internal load parameters in 3 × 3 basketball tournaments

Purpose3 × 3 basketball games are characterized by high-intensity accelerations and decelerations, and a high number of changes of direction and jumps. It is played in tournament form with multiple games per day. Therefore, optimal regeneration is crucial for maintaining a high performance level over the course of the tournament. To elucidate how load of a match affects the athletes' bodies (i.e., internal load), muscular responses to the load of 3 × 3 games were analyzed. We aimed to investigate changes in contractility of the m. rectus femoris (RF) and m. gastrocnemius medialis (GC) in response to the load of single 3 × 3 games and a 3 × 3 tournament.MethodsInertial movement analysis was conducted to capture game load in 3 × 3. Changes in contractility were measured using tensiomyography (TMG). During a two-day tournament, TMG measurements were conducted in the morning and after each game. Additionally, off-game performance analysis consisting of jump and change-of-direction (COD) tests was conducted the day before the tournament.ResultsSignificant changes of the muscle contractility were found for GC with TMG values being higher in the baseline than in the post-game measurements. In contrast to athletes of the GC group, athletes of the RF group responded with either decreased or increased muscle contractility after a single 3 × 3 game. A significant correlation between external and internal load parameters could not be shown. Concerning off-game performance, significant correlations can be reported for COD test duration, CMJ height and ∆Vc as well as COD test duration and ∆Dm. No systematic changes in muscle contractility were found over the course of the tournament in RF and GC.ConclusionThe athletes' external 3 × 3 game load and their performance level did not seem to affect muscular contractility after a single 3 × 3 game or a complete 3 × 3 tournament within this investigation. This might indicate that elite athletes can resist external load without relevant local muscular fatigue. With respect to the course of the tournament, it can therefore be concluded that the breaks between games seem to be sufficient to return to the initial level of muscle contractility.

Comparison of The Effect of High- and Low-Frequency Vibration Foam Rolling on The Quadriceps Muscle.

Vibration foam rolling (VFR) intervention has recently gained attention in sports and rehabilitation settings since the superimposed vibration with foam rolling can affect several physiological systems. However, the sustained effect and a comparison of the effects of different VFR vibration frequencies on flexibility and muscle strength have not been examined. Therefore, in this study, we aimed to investigate the acute and sustained effects of three 60-s sets of VFR with different frequencies on knee flexion range of motion (ROM) and muscle strength of the knee extensors. Using a crossover, random allocation design, 16 male university students (21.2 ± 0.6 years) performed under two conditions: VFR with low (35 Hz) and high (67 Hz) frequencies. The acute and sustained effects (20 min after intervention) of VFR on knee flexion ROM, maximum voluntary isometric contraction (MVC-ISO) torque, maximum voluntary concentric contraction (MVC-CON) torque, rate of force development (RFD), and single-leg countermovement jump (CMJ) height were examined. Our results showed that knee flexion ROM increased significantly (p &lt; 0.01) immediately after the VFR intervention and remained elevated up to 20 min, regardless of the vibration frequency. MVC-ISO and MVC-CON torque both decreased significantly (p &lt; 0.01) immediately after the VFR intervention and remained significantly lowered up to 20 min, regardless of the vibration frequency. However, there were no significant changes in RFD or CMJ height. Our results suggest that VFR can increase knee flexion ROM but induces a decrease in muscle strength up to 20 min after VFR at both high and low frequencies.

Altered countermovement jump force profile and muscle-tendon unit kinematics following combined ballistic training.

Combined heavy‐ and light‐load ballistic training is often employed in high‐performance sport to improve athletic performance and is accompanied by adaptations in muscle architecture. However, little is known about how training affects muscle‐tendon unit (MTU) kinematics during the execution of a sport‐specific skill (e.g., jumping), which could improve our understanding of how training improves athletic performance. The aim of this study was to investigate vastus lateralis (VL) MTU kinematics during a countermovement jump (CMJ) following combined ballistic training. Eighteen young, healthy males completed a 10‐week program consisting of weightlifting derivatives, plyometrics, and ballistic tasks under a range of loads. Ultrasonography of VL and force plate measurements during a CMJ were taken at baseline, mid‐test, and post‐test. The training program improved CMJ height by 11 ± 13%. During the CMJ, VL's MTU and series elastic element (SEE) length changes and velocities increased from baseline to post‐test, but VL's fascicle length change and velocity did not significantly change. It is speculated that altered lower limb coordination and increased force output of the lower limb muscles during the CMJ allowed more energy to be stored within VL's SEE. This may have contributed to enhanced VL MTU work during the propulsion phase and an improved CMJ performance following combined ballistic training.

Regional Lean Soft Tissue and Intracellular Water Are Associated with Changes in Lower-Body Neuromuscular Performance: A Pilot Study in Elite Soccer Players.

The assessment of body composition over a competitive season provides valuable information that can help sports professionals to evaluate the efficacy of training and nutritional strategies, as well as monitoring athletes’ health status. The purpose of this study was to examine the association of changes in body composition and hydration status with changes in lower-body neuromuscular performance in soccer. Twenty-two male professional soccer players (mean ± SD; age: 26.4 ± 4.8 years; height: 184.3 ± 5.7 cm; body mass: 81.1 ± 6.5 kg; body fat: 11.6 ± 1.5%) took part in the study, for which they were tested at the initial and final stage of the competitive season. Total (whole body) and regional (arms and legs) lean soft tissue (LST) were estimated to obtain the body composition profile. Total body water (TBW) content, including extracellular (ECW) and intracellular (ICW) water, was obtained to monitor players’ hydration status. Countermovement jump (CMJ) height, power, and strength were used to derive players’ lower-body neuromuscular performance. The results showed that changes in legs LST and ICW significantly (p < 0.01) explained (r2 = 0.39) the improvements in CMJ height, power, and strength from the initial to the final stage of the season. Given the high demand imposed on the lower limbs during a soccer season, being more susceptible to change compared to whole-body LST, assessing regional LST and ICW would be more appropriate to provide extended information on players’ readiness.

Movement Velocity as a Determinant of Actual Intensity in Resistance Exercise.

This study aimed to analyze the acute mechanical, metabolic and EMG response to five resistance exercise protocols (REP) in the full squat (SQ) exercise performed with two velocity conditions: maximal intended velocity (MaxV) vs. half-maximal velocity (HalfV). Eleven resistance-trained men performed 10 REP (5 with each velocity conditions) in random order (72-96 h apart). The REP consisted of three sets of 8-3 repetitions against 45-65% 1RM. The percent change in countermovement jump (CMJ) height, velocity attained with the load that elicited a ~1.00 m·s-1 (V1-load), surface EMG variables and blood lactate concentration were assessed pre- vs. post-exercise protocols. MaxV resulted in greater percent changes (Δ: 12-25%) and intra-condition effect sizes (ES: 0.76-4.84) in loss of V1-load and CMJ height compared to HalfV (Δ: 10-16%; ES: 0.65-3.90) following all REP. In addition, MaxV showed higher post-exercise lactate concentration than HalfV (ES: 0.46-0.83; p<0.05). For EMG variables, only the Dimitrov index resulted in relevant changes after each REP, with MaxV showing greater magnitude of changes (23-38%) than HalfV (12-25%) across all REP. These results suggest that voluntary movement velocity is a key aspect to consider since it clearly determines the overall training intensity during resistance exercise.