Countermovement Vertical Jump Performance Research Articles

Changes in Countermovement Vertical Jump Force-Time Metrics Across Different Competitive Levels in Women’s Volleyball

As one of the most fundamental skills in volleyball, the countermovement vertical jump (CVJ) has been commonly implemented as a non-invasive and time-efficient method for the assessment of lower-body neuromuscular function. The purpose of the present study was to examine differences in CVJ performance between three different competitive levels in female volleyball players (i.e., national team [n=20], professional league [n=16], collegiate [n=16]). While standing on a uni-axial force plate system sampling at 1000 Hz, athletes performed three maximal-effort CVJs with no arm swing (i.e., hands on the hips during the entire movement). Each jump was separated by a 10-15 second rest interval to minimize the possible influence of fatigue. Significantly greater eccentric braking impulse, peak velocity, peak force, mean and peak power, vertical jump height, reactive strength index-modified, countermovement depth, and shorter braking phase, eccentric duration, and contraction times were observed for the national team and professional players when compared to collegiate athletes. Also, national team players demonstrated significantly greater eccentric braking impulse, peak velocity, mean and peak power, reactive strength index-modified, and countermovement depth than professional volleyball players. However, during the concentric phase of the CVJ, the only significant differences observed were between national team players and collegiate athletes, where national team players exhibited significantly greater peak velocity, impulse, and mean and peak power. Thus, it can be concluded that higher-level players may be more capable of effectively utilizing the eccentric phase of the CVJ and executing the stretch-shortening action more rapidly, which contributes to better CVJ height.

Comparison of vertical jump and sprint performances between 3 × 3 and 5 × 5 elite professional male basketball players.

Given its fast-growing popularity and unique on-court competitive demands, 3 × 3 basketball has captured a considerable amount of attention over recent years. However, unlike research focused on studying 5 × 5 basketball players, there is a lack of scientific literature focused on examining countermovement vertical jump (CMJ) and sprint performance characteristics of 3 × 3 athletes. Thus, the purpose of the present study was to compare force-time metrics during both eccentric and concentric phases of the CMJ and acceleration and deceleration capabilities between 3 × 3 and 5 × 5 top-tier professional male basketball athletes. Ten 3 × 3 and eleven 5 × 5 professional basketball players volunteered to participate in the present study. Upon completion of a standardized warm-up, each athlete performed three maximum-effort CMJs, followed by two 10 m sprints. A uni-axial force plate system sampling at 1,000 Hz was used to analyze CMJ force-time metrics and a radar gun sampling at 47 Hz was used to derive sprint acceleration-deceleration measures. Independent t-tests and Hedge's g were used to examine between-group statistically significant differences (p < 0.05) and effect size magnitudes. The findings of the present study reveal that 3 × 3 and 5 × 5 professional male basketball players tend to display similar neuromuscular performance characteristics as no significant differences were observed in any force-time metric during both eccentric and concentric phases of the CMJ (g = 0.061-0.468). Yet, prominent differences were found in multiple measures of sprint performance, with large effect size magnitudes (g = 1.221-1.881). Specifically, 5 × 5 basketball players displayed greater average and maximal deceleration and faster time-to-stop than their 3 × 3 counterparts. Overall, these findings provide reference values that sports practitioners can use when assessing athletes' CMJ and sprint performance capabilities as well as when developing sport-specific training regimens to mimic on-court competitive demands.

Comparison of Force-Time Metrics Between Countermovement Vertical Jump With and Without an Arm Swing in Professional Male Basketball Players

With technological developments over the last decade, a wide range of countermovement vertical jump (CMJ) force-time metrics can be derived from commercially available portable force plate systems. However, it should be noted that how the test is performed can have a substantial impact on the outcome of the assessment. Thus, the purpose of the present study was to determine differences in biomechanical variables between CMJ with and without an arm swing in a cohort of elite athletes. Ten professional male basketball players volunteered to participate in the present study. Following a standardized warm-up procedure, athletes stepped on a uni-axial force plate sampling at 1000 Hz and performed three CMJ without arm swing (i.e., hands on the hips) followed by three CMJ with an arm swing (i.e., arms positioned slightly in the front of the body with elbows flexed at a 90-degree angle). To minimize the possible influence of fatigue, each jump was separated by a 15-30 s rest interval. The findings of the present study indicate phase- specific differences in multiple force-time metrics between the two CMJ testing modalities. While having greater eccentric duration, CMJ with an arm swing had lower eccentric braking and deceleration rate of force development and lower eccentric peak force when compared to CMJ without an arm swing. During the concentric phase of the jump, concentric duration, impulse, peak velocity, and peak power were significantly greater in favor of CMJ with an arm swing. Also, despite longer contraction time, incorporating an arm swing resulted in greater vertical jump heights. Overall, these data describe the CMJ performance of professional male basketball players and provide helpful information for practitioners when designing assessment protocols to monitor athletes’ neuromuscular performance.

Seasonal Change in Countermovement Jump Performance in NCAA Women’s Golfers

Background of Study: The countermovement vertical jump (CMJ) task has been reported to have positive associations with golf-specific performance variables. Additionally, the CMJ is commonly used to assess neuromuscular fatigue in athletic populations. Objective: Thus, this investigation sought to examine the changes in CMJ performance throughout a competitive season in NCAA collegiate women’s golfers. Methods: Using a longitudinal study design, six collegiate women golfers completed three sessions (pre, mid, and post) of CMJ testing during the spring competition period. During each testing session, two successful jump trials were collected using a portable force platform sampling at 1000 Hz. During each trial, an arm swing was restricted by the use of a dowel placed across the upper back. A one-way repeated measures analysis of variance was used to determine if differences were present between testing sessions. Results: Propulsive net impulse significantly increased from pre to mid (p 0.05) and pre to post (p 0.05). No other variables showed a statistically significant change over the duration of the study, though moderate effect size increases were in countermovement depth from pre to mid-testing (0.73) and jump height from pre to post-testing (0.72). Conclusions: These findings support previous findings of an increase in vertical jump performance over the course of a season in collegiate golfers, though strategies for maximal performance may shift.

Relationships among countermovement vertical jump performance metrics, strategy variables, and inter-limb asymmetry in females

ABSTRACT Dependent variables commonly studied during countermovement vertical jump (CMVJ) tests largely stem from male-only studies despite females’distinct energy storage and reutilisation strategies. This could limit progress among females seeking increased CMVJ performance through targeted changes in certain variables. We explored relationships between CMVJ performance metrics (jump height, modified reactive strength index, jump power, and takeoff momentum) and (a) temporal and force application variables and (b) inter-limb force and yank (i.e., rate of force development) asymmetry in 31 recreationally active females. Participants performed eight CMVJs while ground reaction force (GRF) data were obtained. Pearson product-moment correlation coefficients assessed the strength and direction of the associations. Twenty-six significant relationships (r ≥ ±0.357; p < 0.05) were detected across the CMVJ performance variables. The significantly correlated variables were generally isolated to only one of the four performance metrics. Only the percentage of concentric phase inter-limb force asymmetry was significantly associated with CMVJ performance, specifically jump power and takeoff momentum. Coaches and physical performance professionals should be aware of popular strategy variables’ association or lack of association with commonly studied performance metrics when seeking to understand or improve specific CMVJ jumping abilities in females.

MATLAB Guide for Analyzing Countermovement Jump Strategies and Performance Over Time

ABSTRACT Valid and reliable countermovement vertical jump (CMJ) assessments using force platforms can require complex data analysis processes not typically explored during strength and conditioning professionals' training. Although commercially available software programs with focused functionality for force platform-based CMJ analyses have become accessible to help simplify the process, such programs require costly annual subscriptions and can promote reliance on the “black box” for analysis. The purpose of this report was to provide a guide and template aimed to help strength and conditioning professionals create data analysis programs using MATLAB to monitor CMJ performance and performance changes across multiple testing sessions. The guide focuses on programming strategies to import multiple CMJ trials, treat data (i.e., filtering), calculate performance and strategy variables, and create graphics documenting an athlete's performance changes over time. The provided example script can be used as standalone analysis program for the CMJ, to help coaches learn basic script-writing strategies to create their own analysis programs for the CMJ and other performance tests, or both. Ultimately, strength and conditioning professionals should seek to have ownership of their data and analysis processes, and this guide can help coaches start or continue that process.

Acute Effects of Static and Ballistic Stretching on Muscle-Tendon Unit Stiffness, Work Absorption, Strength, Power, and Vertical Jump Performance.

Gesel, FJ, Morenz, EK, Cleary, CJ, and LaRoche, DP. Acute effects of static and ballistic stretching on muscle-tendon unit stiffness, work absorption, strength, power, and vertical jump performance. J Strength Cond Res 36(8): 2147-2155, 2022-The purpose of this study was to evaluate the effects of static and ballistic stretching on muscle-tendon unit (MTU) stiffness, work absorption (WA), strength, power, and countermovement vertical jump (CMJ) performance. Using a within-subject design, 22 subjects performed 3 separate experimental conditions: no-stretching, ballistic stretching, and static stretching for the quadriceps, hamstrings, gluteus, and plantarflexor muscle groups. After each condition, plantarflexor MTU stiffness, WA, isometric strength, and power were measured, followed by a CMJ on a force plate to obtain peak center of mass velocity, peak power, rate of force development, peak force, work, and vertical jump height. Repeated measures analysis of variance with Bonferroni corrected post-hoc tests were used to detect differences between conditions for plantarflexor and CMJ measures. An acute bout of static stretching significantly reduced WA by 12% ( p = 0.049) and isokinetic power by 8% ( p = 0.047) compared with the control condition but ballistic stretching did not ( p = 0.624, p = 0.692, respectively). Significant positive correlations existed between MTU stiffness, WA, strength, and power ( r = 0.64-0.77, p < 0.001). Despite significant positive correlations between MTU stiffness, WA, and CMJ performance measures ( r = 0.40-0.72, p < 0.001), neither static nor ballistic stretching affected CMJ performance ( p > 0.05). These data show that stiffer MTU that absorb more work (energy) are associated with greater muscle force, power, and CMJ performance. Although an acute bout of static stretching impaired MTU passive-elastic properties and power production, neither static nor ballistic stretching impaired isometric strength or CMJ performance.

Effects of different training strategies with a weight vest on countermovement vertical jump and change-of-direction ability in male volleyball athletes.

Weight vest training (WVT) is a strategy used to improve the physical performance of athletes. The objective of this study was to determine the effects of different training strategies with weight vests on vertical jump and change-of-direction ability (CODA) in male volleyball athletes. Fifteen volleyball athletes (22.87±3.04 years, 83.22±10.84 kg, 1.86±0.69 m) participated in a six-week training programme and were randomized into three groups: weight vest plyometric training (WPG), weight vest technical-tactical training (WTG) and a control group (CG). The additional weight of 7.5% of individual body mass was employed in the experimental groups. Before and after the WVT, athletes performed countermovement vertical jump (CMJ) and CODA (t-test) tests. Two-way ANOVA with repeated measures showed that CMJ height increased in all training groups (P<0.05), with the WTG inducing greater CMJ height gains in comparison to the CG (P<0.05). According to magnitude-based inference, the effects of the WTG strategy were "very likely" beneficial for the CMJ compared to the CG. In addition, t-test time decreased similarly among the three training groups (P<0.05). The results suggested that WVT may be incorporated in a volleyball training routine as an effective strategy for improving the CMJ performance in male volleyball athletes.

Maximalist shoes do not alter performance or joint mechanical output during the countermovement jump

ABSTRACT This study examined potential differences between maximally cushioned (MAX) shoes and standard cushioned (STND) shoes during countermovement vertical jump (CMVJ) performance. Twenty-one males (23[2] y; 86.5[15.4] kg; 179.8[6.3] cm) completed eight jumps each in MAX and STND shoes while three-dimensional kinematic and kinetic data were collected. Paired-samples t-tests (α = 0.05) and Cohen’s d effect sizes (ES) were used to compare the following variables: vertical jump displacement, jump time, hip, knee and ankle joint angles at the start of the countermovement, the end of the unloading phase, the end of the eccentric phase, and at takeoff, peak joint power, and the joint contributions to total lower extremity work during the eccentric and concentric phases. The ankle was more dorsiflexed at the end of the countermovement in the MAX shoe (p = 0.002; ES = 0.55) but greater plantarflexion occurred in the STND shoes at takeoff (p = 0.028; ES = 0.56). No other differences were observed. The result of this study suggests that unique ankle joint angular positioning may be employed when wearing MAX versus STND shoes. Since the unique ankle joint positioning did not alter jump performance, potential MAX footwear users might not need to consider the potential for altered CMVJ performance when determining whether to adopt MAX footwear.

Phase-Specific Predictors of Countermovement Jump Performance That Distinguish Good From Poor Jumpers.

Krzyszkowski, J, Chowning, LD, and Harry, JR. Phase-specific predictors of countermovement jump performance that distinguish good from poor jumpers. J Strength Cond Res 36(5): 1257-1263, 2022-The modified-reactive strength index (RSImod) is commonly examined during the countermovement vertical jump (CMJ) to assess neuromuscular characteristics (i.e., explosiveness, fatigue, adaptation, etc.) of an athlete. However, both phase-specific variables explaining RSImod and corresponding differences between good and poor jumpers are not well understood in trained populations. This study sought to (a) identify predictors of RSImod during the CMJ based on phase-specific temporal and rate of force development (RFD) variables, and (b) identify differences in those predictors between performers with high and low RSImod performances from a sample of collegiate male basketball players (n = 22; 20 ± 2 years; 1.99 ± 0.06 month; 93.8 ± 7.5 kg). Subjects performed 3 maximal effort CMJ trials while ground reaction force data was recorded using 2 force platforms. Phase-specific temporal and RFD variables were calculated and entered into separate stepwise regression models using backward elimination to identify predictors RSImod. Individuals were then categorized into high (n = 11; RSImod = 0.68 ± 0.10) and low (n = 11; RSImod = 0.48 ± 0.04) RSImod groups according to the overall median RSImod (RSImod = 0.55). Independent t-tests (α = 0.05) were conducted and supplemented by Cohen's d effect sizes (d ≥ 1.2, large) to compare groups relative to significant predictors identified by the linear regression models and related variables. The temporal regression model (R2 = 0.530) retained unloading time and concentric time, whereas the RFD regression model (R2 = 0.429) retained unloading RFD and braking RFD. The high RSImod group exhibited significantly greater RSImod scores (d = 2.51, p < 0.001) and jump heights (d = 1.58, p < 0.001), shorter times to takeoff (d = 1.27, p = 0.007) and concentric times (d = 1.51, p = 0.002), and a greater braking RFD (d = 1.41, p = 0.005) than the low RSImod group. Individuals targeting enhanced CMJ performance may consider exploring strategies or interventions to develop quicker unloading and concentric phases and increasing eccentric RFD abilities.

The Acute Effects of Different Squat Intensities on Vertical Jump Performance

Andrew R. Hill1,2, Daniel L Laudermilk1, Soon-Mi Choi1. 1Midwestern State University, Wichita Falls, TX, 2Endunamoo Strength & Conditioning, Wichita Falls, TX. Post activation potentiation (PAP) is defined as a short-term improvement in performance as a result of using a resistance exercise. The phenomenon of PAP has been shown to acutely increase athletic performance with back squats as an effective modality. PURPOSE: This study investigated acute effects of different back squat intensities on the countermovement vertical jump (CMJ). METHODS: Participants were 13 to 18-yr-old healthy male (n=8) and female (n=3) who participated in regular resistance training for at least 6 months and have played in a University Interscholastic League (UIL) within the past 6 months. One Repetition Maximum (1-RM) was measured within 4 weeks before testing and all participants abstained from strenuous exercise for 48 hours prior to testing. Each participant performed a standard warm-up for 5 minutes and measured a baseline (PRE) CMJ by a Vertec ®. One minute of resting interval time was provided after PRE test. The CMJ performed by a randomized counterbalanced order with repeated measures under five different barbell back squat trials: 70, 75, 80, 85, and 90% of 1-RM. Between each barbell back squat trial and CMJ test, the participants rested for one minute. Peak power values were estimated by equation (Harman Formula): Peak power (W) = 61.9 · jump height (cm) + 36.0 · body mass (kg) + 1,822. All Data were represented mean and standard deviation and analyzed by one-way ANOVA with repeated measures. RESULTS: There was no significant difference at 70, 85, and 90% of 1-RM. The CMJ increased significantly in 1-RM 75% (PRE: 51.3 ± 13.9 cm, 75%: 52.8 ± 13.6 cm, p=.036). At 1-RM 80%, increasing tendency was shown (PRE: 51.3 ± 13.9 cm, 80%: 52.8 ± 14.5 cm, p=.069). CONCLUSION: The results may indicate that barbell back squat at 75-80% of 1-RM can improve a CMJ performance acutely in adolescence who plays in UIL level.

Variable, but not free-weight, resistance back squat exercise potentiates jump performance following a comprehensive task-specific warm-up.

Studies examining acute, high-speed movement performance enhancement following intense muscular contractions (frequently called "post-activation potentiation"; PAP) often impose a limited warm-up, compromizing external validity. In the present study, the effects on countermovement vertical jump (CMJ) performance of back squat exercises performed with or without elastic bands during warm-up were compared. After familiarization, fifteen active men visited the laboratory on two occasions under randomized, counterbalanced experimental squat warm-up conditions: (a) free-weight resistance (FWR) and (b) variable resistance (VR). After completing a comprehensive task-specific warm-up, three maximal CMJs were performed followed by three back squat repetitions completed at 85% of 1-RM using either FWR or VR Three CMJs were then performed 30seconds, 4minutes, 8minutes, and 12minutes later. During CMJ trials, hip, knee, and ankle joint kinematics, ground reaction force data and vastus medialis, vastus lateralis, and gluteus maximus electromyograms (EMG) were recorded simultaneously using 3D motion analysis, force platform, and EMG techniques, respectively. No change in any variable occurred after FWR (P>0.05). Significant increases (P<0.05) were detected at all time points following VR in CMJ height (5.3%-6.5%), peak power (4.4%-5.9%), rate of force development (12.9%-19.1%), peak concentric knee angular velocity (3.1%-4.1%), and mean concentric vastus lateralis EMG activity (27.5%-33.4%). The lack of effect of the free-weight conditioning contractions suggests that the comprehensive task-specific warm-up routine mitigated any further performance augmentation. However, the improved CMJ performance following the use of elastic bands is indicative that specific alterations in force-time properties of warm-up exercises may further improve performance.

Kinetic and Electromyographic Subphase Characteristics With Relation to Countermovement Vertical Jump Performance.

This study sought to identify kinetic and electromyographic subphase characteristics distinguishing good from poor jumpers during countermovement vertical jumps (CMVJs), as defined by the reactive strength index (RSI, CMVJ displacement divided by jump time; cutoff = 0.46m·s-1). A total of 15 men (1.8 [0.6]m, 84.5 [8.5]kg, 24 [2]y) were stratified by RSI into good (n = 6; RSI = 0.57 [0.07]m·s-1) and poor (n = 9; RSI = 0.39 [0.06]m·s-1) performance groups. The following variables were compared between groups using independent t tests (α = .05) and Cohen's d effect sizes (d ≥ 0.8, large): jump height, propulsive impulse, eccentric rate of force development, and jump time, unloading, eccentric, and concentric subphase times, and average electromyographic amplitudes of 8 lower extremity muscles. Compared with the poor RSI group, the good RSI group exhibited a greater, though not statistically different CMVJ displacement (d = 1.07, P = .06). In addition, the good RSI group exhibited a significantly greater propulsive impulse (P = .04, d = 1.27) and a significantly more rapid unloading subphase (P = .04, d = 1.08). No other significant or noteworthy differences were detected. Enhanced RSI appears related to a quicker unloading phase, allowing a greater portion of the total jumping phase to be utilized generating positive net force. Poor jumpers should aim to use unloading strategies that emphasize quickness to enhance RSI during CMVJ.

Improving Vertical Jump Profiles Through Prescribed Movement Plans.

Mayberry, JK, Patterson, B, and Wagner, P. Improving vertical jump profiles through prescribed movement plans. J Strength Cond Res 32(6): 1619-1626, 2018-Developing practical, reliable, and valid methods for monitoring athlete wellness and injury risk is an important goal for trainers, athletes, and coaches. Previous studies have shown that the countermovement vertical jump (CMJ) test is both a reliable and valid metric for evaluating an athlete's condition. This study examines the effectiveness of prescribed workouts on improving the quality of movement during CMJ. The data set consists of 2,425 pairs of CMJ scans for high school, college, and professional athletes training at a privately owned facility. During each scan, a force plate recorded 3 ground reaction force (GRF) measurements known to impact CMJ performance: eccentric rate of force development (ERFD), average vertical concentric force (AVCF), and concentric vertical impulse (CVI). After an initial scan, coaches either assigned the athlete a specific 1- or 2-strength movement plan (treatment group) or instructed the athlete to choose their own workouts (control group) before returning for a follow-up scan. A multivariate analysis of covariance (MANCOVA) revealed significant differences in changes to GRF measurements between athletes in the 2 groups after adjusting for the covariates sex, sport, time between scans, and rounds of workout completed. A principal component analysis of GRF measurements further identified 4 primary groups of athlete needs and the results provide recommendations for effective workout plans targeting each group. In particular, split squats increase CVI and decrease ERFD/AVCF; deadlifts increase AVCF and decrease CVI; alternating squats/split squats increase ERFD/CVI and decrease AVCF; and alternating squats/deadlifts increase ERFD/AVCF and decrease CVI.

An examination of action capabilities and movement time during a soccer anticipation task

This study examined the anticipation responses of twenty skilled youth players who were assigned to either a change of direction (CODG) or small-sided games group (SSGG). Action capabilities were assessedviaa countermovement vertical jump (CMVJ), 20 m sprint, 5 m acceleration and arrowhead change of direction (COD) test. Anticipation was measuredviaa soccer-specific anticipation test (SSAT), which required participants to anticipate the actions of an opposing player and intercept a pass. Pre- and post-intervention testing procedures were identical for both groups. Following training there was an overall improvement in CMVJ performance (p &lt; 0.05,r = 0.52) for both training groups and this improvement was correlated with movement initiation in the SSAT (r = 0.61,p &lt; 0.05). The novel findings of this study highlight that different training modes can potentially have a positive impact on anticipation performance. Further investigation focussing on an examination of the relationship between training, anticipation, and action capabilities in sport is warranted for the development of research and applied perspectives in expertise.

Effect of an Arm Swing on Countermovement Vertical Jump Performance in Elite Volleyball Players: FINAL.

The aim of this study was to determine how elite volleyball players employed the arm swing (AS) to enhance their jump performance. The study assessed how the AS influenced the duration and magnitude of the vertical ground reaction force (VGRF) during the main phases (preparatory, braking and accelerating) of the countermovement vertical jump (CMVJ), the starting position of the body at the beginning of the accelerating phase and the moment when the AS began contributing to increasing the jump height. Eighteen elite volleyball players performed three CMVJs with and without an AS. Kinetics and kinematics data were collected using two Kistler force plates and the C-motion system. The time and force variables were evaluated based on the VGRF, and the position of the body and the trajectory of the arm movement were determined using kinematic analysis. The AS improved the CMVJ by increasing the jump height by 38% relative to jumping without an AS. The AS significantly shortened the braking phase and prolonged the accelerating phase, however, it did not influence the preparatory phase or the overall jump duration. The AS also significantly increased the average force during the accelerating phase as well as the accelerating impulse. The AS upward began at 76% into the overall jump duration. The AS did not influence the body position at the beginning of the accelerating phase. These findings can be used to improve performance of the CMVJ with the AS and in teaching beginning volleyball players proper jumping technique.

Associations between Testosterone, Body Composition, and Performance Measures of strength and Power in Recreational, Resistance- Trained Men

Associations between Testosterone, Body Composition, and Performance Measures of strength and Power in Recreational, Resistance- Trained Men The objective of the current cross-sectional study was to determine whether relationships existed between testosterone (TEST), back squat (BS) one-repetition maximum (1RM), body composition, and power-oriented tests of horizontal ((standing long jump (SLJ)) and vertical ((countermovement vertical jump (CMVJ)) jumping ability in recreational, resistance-trained males. Twenty-nine men (mean ± SD; age 26.2 ± 4.5 years; height 176.6 ± 6.9 cm; weight 84.7 ± 11.7 kg; 15.2 ± 6.3 % body fat) participated. Total TEST, body composition, SLJ, CMVJ, and BS 1RM were assessed. Lower body power output was calculated from body mass and CMVJ height. Bivariate (Pearson) correlations were computed to determine significance (p<0.05). The 1RM BS-to-body-mass ratio was 1.80 ± 0.2. Total TEST was 34.3 ± 10.2 nmol•L-1. There were correlations between lean mass (LM) and peak power (r=0.48; p=0.01), LM and BS 1RM (r=0.64; p=0.001), BS 1RM and peak power (r=0.70, p=0.001), and CMVJ and SLJ (r=0.57, p=0.001). There were no correlations between TEST and performance measures (SLJ, r= -0.03; CMVJ, r= -0.18; 1RM BS, r= -0.21). Total TEST levels are not correlated with performance measures of lower body strength and power in this population; however, BS 1RM is correlated with lower body power and LM. TEST cannot be used to predict select measures of performance in a cross-sectional sample of recreational lifters, but consistent adherence to recreational resistance training may have a positive effect on SLJ and CMVJ performance.

Effects of Muscle Action Type With Equal Impulse of Conditioning Activity on Postactivation Potentiation

This study investigated the effects of muscle action type during conditioning activity (half-squat) on subsequent vertical jump performance. Fourteen track and field athletes (relative half-squat of 2.3 ± 0.3 times their body weight) completed 4 main trials in a randomized and counterbalanced order 5-7 days apart: (a) concentric (CON) half-squats: 7.5 ± 1.2 repetitions against 90% of 1 repetition maximum (1RM), (b) eccentric (ECC) half-squats: 9.3 ± 1.5 repetitions against 70% of 1RM, and (c) 3 sets of 3-second maximal isometric (ISO) half-squats, (d) a control (CTRL) trial, where subjects rested for 10 minutes. The number of repetitions in CON and ECC was adjusted so that the impulse of the vertical ground reaction force was similar to ISO. Countermovement vertical jump (CMJ) performance was evaluated for 21 minutes after each main trial. Countermovement vertical jump performance in ISO was higher than CTRL from the second to the 10th minute of recovery, whereas CMJ performance in ECC was higher than CTRL from the sixth and 10th minute of recovery. Analysis of the peak individual responses revealed an increase in CMJ performance compared with baseline only in ISO (3.0 ± 1.2%; p = 0.045), whereas no significant increases were observed in ECC and CON. Peak CMJ performance for all subjects in ISO and ECC was achieved within 2-10 minutes after the conditioning muscle actions. Isometric were more effective than CON and ECC muscle actions in increasing explosive leg performance when the impulse of the ground reaction force of the conditioning exercise was equated.

Effect of Hang Cleans Or Squats Paired With Countermovement Vertical Jumps on Vertical Displacement

Complex training is characterized by pairing resistance exercise with plyometric exercise to exploit the postactivation potentiation (PAP) phenomenon, thereby promising a better training effect. Studies on PAP as measured by human power performances are equivocal. One issue may be the lack of analyses across multiple sets of paired exercises, a common practice used by athletes. We evaluated countermovement vertical jump (CMJ) performance in 19 women, collegiate athletes in 3 of the following trials: (a) CMJs-only, where 1 set of CMJs served as a conditioning exercise, (b) heavy-load, back squats paired with CMJs, and (c) hang cleans paired with CMJs. The CMJ vertical displacement (3-attempt average), as measured with digital video, served as the dependent variable of CMJ performance. Across 3 sets of paired-exercise regimens, CMJ-only depreciated 1.6 cm and CMJ paired with back squats depreciated 2.0 cm (main effect, p < 0.05). Conversely, CMJ paired with hang cleans depreciated 0.30 cm (interaction, p < 0.05). Thus, the best complex training scheme was achieved by pairing CMJs with hang cleans in comparison to back squats or CMJs in and of themselves. Future research on exercise modes of complex training that best help athletes preserve and train with the highest power possible, in a given training session, is warranted.

The Acute Effects of Manipulating Volume and Load of Back Squats on Countermovement Vertical Jump Performance

The acute effects of manipulating the volume and load of back squats on subsequent countermovement vertical jump performance were investigated in the present study. Eleven National Collegiate Athletic Association division II female volleyball players performed 10 countermovement vertical jumps (CMJs) on a force platform 2 minutes after the last squat repetition of a high-load (HL) or high-volume (HV) squat protocol. Two minutes of rest was provided between each CMJ. The HL protocol culminated in the subjects having to perform 3 repetitions with a load equivalent to 90% 1 repetition maximum (1RM) back squat, whereas 12 repetitions with a load equivalent to 37% 1RM were performed in the HV protocol. During an initial familiarization session, knee angles were recorded during a series of CMJs, and these angles were used to control the depth of descent during all subsequent back squats. Jump height (JH) and vertical stiffness (VStiff) were calculated during each of the 10 CMJ, and the change in these variables after the 2 squat protocols was assessed using an analysis of variance model with repeated measures on 2 factors (Protocol [2-levels]; Time [2-levels]). There was no significant difference in JH after the HL and HV protocols (p > 0.05). A significant Protocol × Time interaction for VStiff resulted from the increase after the HL protocol being greater than that after the HV protocol (p = 0.03). The knee angles before the HL and HV protocols were significantly greater than those measured during the initial familiarization session (p = 0.001). Although neither squat protocol provided any benefit in improving JH, the heavy squat protocol produced greater increases in VStiff during the CMJ. Because of the increased VStiff caused by the HL protocol, volleyball coaches may consider using such protocols with their players to improve performance in jumps performed from a run such as the spike and on-court agility.