The Functional Movement Screen and Self-reported Injury in Senior Military College Cadets.

INTRODUCTION: Secular trend of increasing musculoskeletal injuries (MSKIs) across all branches of the U.S. Military is a critical limiting factor in the effective and efficient process of preparing military personnel for combat. The need to evaluate functional capacity beyond current physical fitness test (PFT) standards is the key in understanding an individual's risk of noncombat-related injury. The purpose of this study is to evaluate the relationship between Functional Movement ScreenTM (FMS) scores, incidence of musculoskeletal injuries, and standardized PFT scores among freshman Cadets during their first 10 weeks of enrollment at a senior military college. MATERIALS AND METHODS: Eighty-two participants (72 male and 10 female participants; mage: 18.2 years) completed the FMS, an institution-specific PFT (2-min maximum pushups, 2-min maximum abdominal crunches, and 1.5 mile timed run), and an Incidence of Injury and Incidence of Pain Questionnaire. Independent t-tests, Spearman's rank correlation coefficients logistic regression analysis, and Receiver Operator Curves were performed to evaluate relationships between the study variables. RESULTS: FMS composite and PFT sex-normed total scores were higher in females (16.4, 236.1) than in males (15.0, 204.9). Ninety percent of all females reported injury or pain during the 10-week survey period compared to 48% of males. CONCLUSIONS: No significant difference between FMS scores and injury and pain was found within both sex groups. Therefore, use of the composite FMS score as an indicator for risk of injury or to predetermine PFT performance is not recommended for this study's population. The rate of incidence of injury or pain in Cadets during a 10-week enrolment period is high. Females outperformed males in the FMS and PFT and reported higher rates of injury and pain. The utility of the FMS may be limited when substantially scaled for implementation across entire military populations. Future research should evaluate performance associations of the FMS with Army Combat Fitness Test components in a population of equally distributed sex and race.

Effect of Neuromuscular Fatigue on the Countermovement Jump Characteristics: Basketball-Related High-Intensity Exercises.

ABSTRACT: Yoshida, N, Hornsby, WG, Sole, CJ, Sato, K, and Stone, MH. Effect of neuromuscular fatigue on the countermovement jump characteristics: basketball related high-intensity exercises. J Strength Cond Res 38(1): 164-173, 2024-The purpose of this study was to investigate basketball specific neuromuscular (NM) fatigue effect on countermovement jump (CMJ) force-time (F-T) curve characteristics. Eleven male college-level basketball athletes performed 6 CMJ trials at 3 baseline (pre) and 6 postexercise time points. The fatiguing protocol consisted of high-intensity basketball related exercises commensurate with basketball game or practice. Typical CMJ (CMJ-TYP) and phase-specific CMJ variables were derived from the F-T curve. Meaningful differences in CMJ performance were examined using effect size (ES) compared with baseline and previous postexercise time point. Baseline with 3 separated measurements demonstrated suitable CMJ variables reproducibility (CV, coefficient of variation). Most CMJ-TYP output and performance variables displayed substantial alterations immediately postexercise (0 hour) and returned to baseline at 24 hours postexercise, whereas the time and rate-related CMJ-TYP and CMJ-phase variables tended to display delayed decline peaked at 2 hours and delayed recovery to baseline at 48 hours postexercise. In conjunction with the return of the time and rate-related variables, CMJ performance displayed supercompensation at 72 hours postexercise. The results indicate altered NM functions with desired CMJ performance, such as jump height, which imply an altered movement strategy at early stage of recovery process. Full recovery may take 48-72 hours. Practitioners are, therefore, advised to monitor variables reflecting NM functions for precise manipulation of the intensity and volume of exercise to avoid prolonging the recovery from NM fatigue.

The Pathophysiology of Osteoporosis after Spinal Cord Injury.

Spinal cord injury (SCI) affects approximately 300,000 people in the United States. Most individuals who sustain severe SCI also develop subsequent osteoporosis. However, beyond immobilization-related lack of long bone loading, multiple mechanisms of SCI-related bone density loss are incompletely understood. Recent findings suggest neuronal impairment and disability may lead to an upregulation of receptor activator of nuclear factor-κB ligand (RANKL), which promotes bone resorption. Disruption of Wnt signaling and dysregulation of RANKL may also contribute to the pathogenesis of SCI-related osteoporosis. Estrogenic effects may protect bones from resorption by decreasing the upregulation of RANKL. This review will discuss the current proposed physiological and cellular mechanisms explaining osteoporosis associated with SCI. In addition, we will discuss emerging pharmacological and physiological treatment strategies, including the promising effects of estrogen on cellular protection.

Dynamic Strength Index: Relationships with Common Performance Variables and Contextualization of Training Recommendations.

The purposes of this study were to examine the relationships between dynamic strength index (DSI) and other strength-power performance characteristics and to contextualize DSI scores using case study comparisons. 88 male and 67 female NCAA division I collegiate athletes performed countermovement jumps (CMJ) and isometric mid-thigh pulls (IMTP) during a pre-season testing session as part of a long-term athlete monitoring program. Spearman's correlations were used to assess the relationships between DSI and CMJ peak force, height, modified reactive strength index, peak power and IMTP peak force and rate of force development (RFD). Very large relationships existed between DSI and IMTP peak force (r = -0.848 and -0.746), while small-moderate relationships existed between DSI and CMJ peak force (r = 0.297 and 0.313), height (r = 0.108 and 0.167), modified reactive strength index (r = 0.174 and 0.274), and IMTP RFD (r = -0.341 and -0.338) for men and women, respectively. Finally, relationships between DSI and CMJ peak power were trivial-small for male (r = 0.008) and female athletes (r = 0.191). Case study analyses revealed that despite similar DSI scores, each athlete's percentile rankings for each variable and CMJ force-time characteristics were unique, which may suggest different training emphases are needed. Based on the explained variance, an athlete's IMTP performance may have a larger influence on their DSI score compared to the CMJ. DSI scores should be contextualized using additional performance data to ensure each individual athlete receives the appropriate training stimulus during different training phases throughout the year.

Intrasession and Intersession Reliability of Countermovement Jump Testing in Division-I Volleyball Athletes.

Carroll, KM, Wagle, JP, Sole, CJ, and Stone, MH. Intrasession and intersession reliability of countermovement jump testing in Division-I volleyball athletes. J Strength Cond Res 33(11): 2932-2935, 2019-The countermovement jump (CMJ) is a reliable and noninvasive test of lower-body neuromuscular performance. Many of the investigations used to establish the reliability of CMJ have been conducted in a controlled environment (i.e., laboratory setting). To better inform coaches, reliability of key CMJ variables should be examined in a practical environment. This study assessed intrasession and intersession reliability of CMJ variables in NCAA D-I volleyball athletes. Eleven female volleyball players (age = 19.8 ± 0.8 years, height = 1.75 ± 0.07 m, body mass = 71.6 ± 8.9 kg) performed twice weekly CMJ testing on force platforms across 14 weeks of training. Dependent variables were CMJ height (CMJH), reactive strength index modified (RSIMOD), relative peak power (rPP), and countermovement depth (CM depth). Intraclass correlation coefficients (ICCs), coefficient of variation (CV), and typical error (TE) were calculated, along with Pearson correlation coefficients. Intrasession reliability revealed excellent reliability values for CMJH (ICC = 0.94, CV = 2.9 ± 2.4%, TE = 1.25) and RSIMOD (ICC = 0.93, CV = 4.7 ± 4.9, TE = 0.03). Good reliability values were observed for rPP (ICC = 0.79, CV = 6.1 ± 10.9%, TE = 4.48), with only moderate reliability for CM depth (ICC = 0.61, CV = 7.1 ± 10.9%, TE = 16.9). Intersession reliability indicated excellent reliability for CMJH (ICC = 0.92, CV = 3.2 ± 2.8%, TE = 1.4) and RSIMOD (ICC = 0.92, CV = 5.4 ± 4.3%, TE = 0.03). However, poor reliability was observed for rPP (ICC = 0.41, CV = 10.4 ± 15.4%, TE = 7.95) and CM depth (ICC = 0.39, CV = 7.7 ± 10.8%, TE = 6.42). These results suggest that in the context of weekly athlete monitoring, measures such as CMJH and RSIMOD exhibit the greatest reliability. Conversely, measures such as CM depth and rPP exhibit high levels of variability. Practitioners seeking to track jump performance over time should be cognizant of CM depth variability and its potential impact on CMJ variables.

Influence of Sex and Maximum Strength on Reactive Strength Index-Modified.

Reactive strength index-modified (RSImod) is a measure of lower body explosiveness calculated by dividing jump height by time to takeoff. RSImod is different between stronger and weaker athletes and between males and females. The purpose of this study was to evaluate differences in RSImod between males and females while controlling for maximal strength and lower body explosiveness. Forty-three female and fifty-eight male Division-I athletes performed countermovement jumps on a force plate during unloaded (0kg) and loaded (20kg) conditions. We used an ANCOVA to test whether RSImod is different between sexes conditioning on relative maximum strength (PFa) and average RFD 0-200ms (RFD200) measured during the isometric mid- thigh pull (IMTP). Differences of 0.087 (95% CI: 0.040-0.134; p = 0.0005) and 0.075 (95% CI: 0.040-0.109, p < 0.0001) were observed for RSImod between sexes in unloaded and loaded conditions, respectively. A male with PFa of 186 (grand mean of the sample) and RFD200 of 6602 N/s (grand mean of the sample) is predicted to have 28% greater RSImod than a female of similar PFa and RFD200. Maximum strength development should be a primary aim of training in female athletes, in addition to other trainable factors, such as stiffness and RFD.

Preliminary Scale of Reference Values for Evaluating Reactive Strength Index-Modified in Male and Female NCAA Division I Athletes.

The purpose of this analysis was to construct a preliminary scale of reference values for reactive strength index-modified (RSImod). Countermovement jump data from 151 National Collegiate Athletic Association (NCAA) Division I collegiate athletes (male n = 76; female n = 75) were analyzed. Using percentiles, scales for both male and female samples were constructed. For further analysis, athletes were separated into four performance groups based on RSImod and comparisons of jump height (JH), and time to takeoff (TTT) were performed. RSImod values ranged from 0.208 to 0.704 and 0.135 to 0.553 in males and females, respectively. Males had greater RSImod (p < 0.001, d = 1.15) and JH (p < 0.001, d = 1.41) as compared to females. No statistically significant difference was observed for TTT between males and females (p = 0.909, d = 0.02). Only JH was found to be statistically different between all performance groups. For TTT no statistical differences were observed when comparing the top two and middle two groups for males and top two, bottom two, and middle two groups for females. Similarities in TTT between sexes and across performance groups suggests JH is a primary factor contributing to differences in RSImod. The results of this analysis provide practitioners with additional insight as well as a scale of reference values for evaluating RSImod scores in collegiate athletes.

Force-Time Differences between Ballistic and Non-Ballistic Half-Squats.

The purpose of this study was to examine the force-time differences between concentric-only half-squats (COHS) performed with ballistic (BAL) or non-ballistic (NBAL) intent across a range of loads. Eighteen resistance-trained men performed either BAL or NBAL COHS at 30%, 50%, 70%, and 90% of their one repetition maximum (1RM) COHS. Relative peak force (PF) and relative impulse from 0⁻50 ms (Imp50), 0⁻90 ms (Imp90), 0⁻200 ms (Imp200), and 0⁻250 ms (Imp250) were compared using a series of 2 × 4 (intent × load) repeated measures ANOVAs with Bonferroni post hoc tests. Cohen's d effect sizes were calculated to provide measures of practical significance between the BAL and NBAL COHS and each load. BAL COHS produced statistically greater PF than NBAL COHS at 30% (d = 3.37), 50% (d = 2.88), 70% (d = 2.29), and 90% 1RM (d = 1.19) (all p < 0.001). Statistically significant main effect differences were found between load-averaged BAL and NBAL COHS for Imp90 (p = 0.006, d = 0.25), Imp200 (p = 0.001, d = 0.36), and Imp250 (p < 0.001, d = 0.41), but not for Imp50 (p = 0.018, d = 0.21). Considering the greater PF and impulse observed during the BAL condition, performing COHS with BAL intent may provide a favorable training stimulus compared to COHS performed with NBAL intent.

Jumping Performance is Preserved but Not Muscle Thickness in Collegiate Volleyball Players After a Taper.

Bazyler, CD, Mizuguchi, S, Sole, CJ, Suchomel, TJ, Sato, K, Kavanaugh, AA, DeWeese, BH, and Stone, MH. Jumping performance is preserved but not muscle thickness in collegiate volleyball players after a taper. J Strength Cond Res 32(4): 1020-1028, 2018-The purpose of this study was to examine changes in muscle architecture and jumping performance in NCAA division I women's volleyball players throughout a competitive season and in preparation for conference championships. Ten women volleyball players were tested at preseason (T1), pretaper (T2), and post-taper (T3) on measures of vastus lateralis muscle thickness (MT), pennation angle (PA) and fascicle length (FL) using ultrasonography, and unloaded and loaded squat jump height (SJH) and peak power allometrically scaled to body mass (SJPPa) on a force platform. Rating of perceived exertion training load and strength training volume load were monitored weekly. Player's MT (p < 0.001, Glass's Δ = 2.8) and PA increased (p = 0.02, Δ = 3.9) after in-season training. However, MT decreased after the taper (p = 0.01, Δ = 0.6) but remained elevated above preseason values (p < 0.001, Δ = 1.7). There were no statistical changes in FL, SJH, or SJPPa. Large-to-very large negative relationships (r = -0.51 to -0.81) were observed between preseason relative maximal strength and changes in SJH and SJPPa with various loads over the season. These findings demonstrate that relatively low volumes of strength training and concurrent sport training during a tapering period are capable of preserving jumping performance, but not MT in women's volleyball players; however, jumping performance changes seem to be related to the player's strength level. Stronger players may benefit from an overreaching microcycle before the taper to preserve previously accrued muscular adaptations and jumping performance.

Phase Characteristics of the Countermovement Jump Force-Time Curve: A Comparison of Athletes by Jumping Ability.

Sole, CJ, Mizuguchi, S, Sato, K, Moir, GL, and Stone, MH. Phase characteristics of the countermovement jump force-time curve: a comparison of athletes by jumping ability. J Strength Cond Res 32(4): 1155-1165, 2018-The purpose of this study was to compare the phase characteristics of the countermovement jump (CMJ) force-time (F-t) curve between athletes based on jumping ability. An initial sample of one-hundred fifty Division-I collegiate athletes were ranked based on CMJ height. Three performance groups were then formed by taking the top, middle, and lower 30 athletes (15 men and 15 women) from the sample. Phases of the CMJ F-t curve were determined and then characterized by their duration, magnitude, area (impulse), and shape (shape factor). A series of 3-way mixed analysis of variance were used to determine statistical differences in phase characteristics between performance groups as well as between male and female athletes. Statistically significant phase-by-performance group interactions were observed for relative phase magnitude (p < 0.001), relative phase impulse (p < 0.001), and shape factor (p = 0.002). Phase-by-sex interactions were statistically significant for both relative phase magnitude (p < 0.001) and relative phase impulse (p < 0.001). Post hoc comparisons indicated that higher jumpers exhibited larger relative magnitude and impulse in the phases contained within the positive area of the F-t curve. Similarly, relative phase magnitude and impulse were the only phase characteristics to be statically different between men and women. Finally, the relative shape of the phase representing the initial rise in force was found to relate to jump height. These results provide some information regarding the diagnostic value of qualitative analysis of the CMJ F-t curve.

Power-Time Curve Comparison between Weightlifting Derivatives.

This study examined the power production differences between weightlifting derivatives through a comparison of power-time (P-t) curves. Thirteen resistance-trained males performed hang power clean (HPC), jump shrug (JS), and hang high pull (HHP) repetitions at relative loads of 30%, 45%, 65%, and 80% of their one repetition maximum (1RM) HPC. Relative peak power (PPRel), work (WRel), and P-t curves were compared. The JS produced greater PPRel than the HPC (p < 0.001, d = 2.53) and the HHP (p < 0.001, d = 2.14). In addition, the HHP PPRel was statistically greater than the HPC (p = 0.008, d = 0.80). Similarly, the JS produced greater WRel compared to the HPC (p < 0.001, d = 1.89) and HHP (p < 0.001, d = 1.42). Furthermore, HHP WRel was statistically greater than the HPC (p = 0.003, d = 0.73). The P-t profiles of each exercise were similar during the first 80-85% of the movement; however, during the final 15-20% of the movement the P-t profile of the JS was found to be greater than the HPC and HHP. The JS produced greater PPRel and WRel compared to the HPC and HHP with large effect size differences. The HHP produced greater PPRel and WRel than the HPC with moderate effect size differences. The JS and HHP produced markedly different P-t profiles in the final 15-20% of the movement compared to the HPC. Thus, these exercises may be superior methods of training to enhance PPRel. The greatest differences in PPRel between the JS and HHP and the HPC occurred at lighter loads, suggesting that loads of 30-45% 1RM HPC may provide the best training stimulus when using the JS and HHP. In contrast, loads ranging 65-80% 1RM HPC may provide an optimal stimulus for power production during the HPC.

Injuries in Collegiate Women's Volleyball: A Four-Year Retrospective Analysis.

A four-year retrospective analysis of injury data was conducted on a collegiate (NCAA Division I) women's volleyball team. Twenty athletes (Year 1: age = 19.4 ± 0.9 y, height = 175.2 ± 5.1 cm, body mass = 70.5 ± 10.2 kg; Year 2: age = 20.1 ± 1.0 y, height = 175.7 ± 4.7 cm, body mass = 69.5 ± 10.1 kg; Year 3: age = 20.1 ± 1.4 y, height = 173.8 ± 6.3 cm, body mass = 69.9 ± 10.8 kg; Year 4: age = 19.5 ± 1.4 y, height = 174.4 ± 8.6 cm, body mass = 72.7 ± 10.8 kg) participated in this study, accounting for 1483 total training exposures. Injury was defined as any damage to a body part, incurred during volleyball or strength and conditioning-related activities, which interfered with training and/or competition. Injury rate was normalized to the number of athletes and exposure and expressed as injuries per 1000 exposures. A total of 133 injuries were recorded. The most common injury was to the knee (left = 7.5%, right = 12.0%). Injuries occurred most often in volleyball practice (75.2%), followed by competition (20.3%), and strength and conditioning-related activities (4.5%). Non-contact injuries (upper body = 26.3%, lower body = 53.4%) were more common than contact injuries (upper-body = 13.5%, lower-body = 6.8%). An examination of injury rates relative to the training year revealed patterns in injury occurrence. Specifically, spikes in injury rate were consistently observed during periods of increased training volume that were preceded by breaks in organized training, such as the early pre-season and off-season training periods.

Force-Time-Curve Comparison Between Weight-Lifting Derivatives.

The force-production characteristics of 3 weight-lifting derivatives were examined by comparing the force-time curves of each exercise. Sixteen resistance-trained men performed repetitions of the hang power clean (HPC), jump shrug (JS), and hang high pull (HHP) on a force platform at several relative loads. Relative peak force (PFRel), relative impulse (IMPRel), peak rate of force development (PRFD), and time-normalized force-time curves of each exercise were compared. The JS produced greater PFRel than the HPC (P < .001, d = 1.38) and HHP (P < .001, d = 1.14), while there was no difference between the HPC and HHP (P = .338, d = 0.26). Similarly, the JS produced greater IMPRel than the HPC (P < .001, d = 0.52) and HHP (P = .019, d = 0.36). The HHP also produced greater IMPRel than the HPC (P = .040, d = 0.18). Finally, the JS produced greater PRFD than the HPC (P < .001, d = 0.73) and HHP (P = .001, d = 0.47), while there was no difference between the HPC and HHP (P = .192, d = 0.22). The HPC, JS, and HHP force-time profiles were similar during the first 75-80% of the movement; however, the JS produced markedly different force-time characteristics in the final 20-25% of the movement. The JS produced superior force-production characteristics, namely PFRel, IMPRel, and PRFD, as well as a unique force-time profile, compared with the HPC and HHP across several loads.

Comparison of Methods That Assess Lower-body Stretch-Shortening Cycle Utilization.

The purpose of this study was to compare 4 methods that assess the lower-body stretch-shortening cycle (SSC) utilization of athletes. Eighty-six National Collegiate Athletic Association Division I athletes from 6 different sports performed 2 squat jumps and 2 countermovement jumps on a force platform. Pre-stretch augmentation percentage (PSAP), eccentric utilization ratio (EUR), and reactive strength (RS) for jump height (JH) and peak power (PP) magnitudes, and reactive strength index-modified (RSImod) were calculated for each team. A series of one-way analyses of variance with a Holm-Bonferroni sequential adjustment were used to compare differences in PSAP, EUR, RS, and RSImod between teams. Statistical differences in RSImod (p < 0.001) existed between teams, whereas no statistical differences in PSAP-JH (p = 0.150), PSAP-PP (p = 0.200), EUR-JH (p = 0.150), EUR-PP (p = 0.200), RS-JH (p = 0.031), or RS-PP (p = 0.381) were present. The relationships between PSAP, EUR, and RS measures were all statistically significant and ranged from strong to nearly perfect (r = 0.569-1.000), while most of the relationships between PSAP, EUR, and RS measures and RSImod were trivial to small (r = 0.192-0.282). Pre-stretch augmentation percentage and EUR, RS, and RSImod values indicate that women's tennis, men's soccer, and men's soccer teams may use the SSC most effectively, respectively. Pre-stretch augmentation percentage, EUR, RS, and RSImod values may show vastly different results when comparing an individual's and a team's ability to use the SSC. Practitioners should consider using RSImod to monitor the SSC utilization of athletes due to its timing component.

A comparison of reactive strength index-modified between six U.S. Collegiate athletic teams.

The purpose of this study was to examine the differences in reactive strength index-modified (RSImod), jump height (JH), and time to takeoff (TTT) between 6 U.S. collegiate sport teams. One hundred six male and female Division I collegiate athletes performed unloaded (<1 kg) and loaded (20 kg) countermovement jumps as part of an ongoing athlete monitoring program. Reactive strength index-modified, JH, and TTT values for each team were compared using 1-way analysis of variance. Statistically significant differences in RSImod (p < 0.001), JH (p < 0.001), and TTT (p = 0.003) existed between teams during the unloaded jumping condition. Similarly, statistically significant differences in RSImod (p < 0.001), JH (p < 0.001), and TTT (p = 0.028) existed between teams during the loaded jumping condition. Men's soccer and baseball produced the greatest RSImod values during both the unloaded and loaded jumping conditions followed by women's volleyball, men's tennis, women's soccer, and women's tennis. The greatest JH during unloaded and loaded jumping conditions was produced by men's baseball followed by men's soccer, women's volleyball, men's tennis, women's soccer, and women's tennis. Men's soccer produced shorter TTT compared with men's baseball (12.7%) and women's soccer (13.3%) during the unloaded and loaded jumping conditions, respectively. Collegiate sport teams exhibit varying reactive strength characteristics during unloaded and loaded jumping conditions. Understanding the differences in RSImod between sports may help direct the creation of training and monitoring programs more effectively for various sports.

Using reactive strength index-modified as an explosive performance measurement tool in Division I athletes.

The purposes of this study included examining the reliability of reactive strength index-modified (RSImod), the relationships between RSImod and force-time variables, and the differences in RSImod between male and female collegiate athletes. One hundred six Division I collegiate athletes performed unloaded and loaded countermovement jumps (CMJs). Intraclass correlation coefficients and typical error expressed as a coefficient of variation were used to establish the relative and absolute reliability of RSImod, respectively. Pearson zero-order product-moment correlation coefficients were used to examine the relationships between RSImod and rate of force development, peak force (PF), and peak power (PP) during unloaded and loaded jumping conditions. Finally, independent samples t-tests were used to examine the sex differences in RSImod between male and female athletes. Intraclass correlation coefficient values for RSImod ranged from 0.96 to 0.98, and typical error values ranged from 7.5 to 9.3% during all jumping conditions. Statistically significant correlations existed between RSImod and all force-time variables examined for male and female athletes during both jumping conditions (p ≤ 0.05). Statistically significant differences in RSImod existed between male and female athletes during both unloaded and loaded CMJs (p < 0.001). Reactive strength index-modified seems to be a reliable performance measurement in male and female athletes. Reactive strength index-modified may be described and used as a measure of explosiveness. Stronger relationships between RSImod, PF, and PP existed in female athletes as compared with that in male athletes; however, further evidence investigating these relationships is needed before conclusive statements can be made. Male athletes produced greater RSImod values as compared with that produced by female athletes.

Mechanical analysis of the acute effects of a heavy resistance exercise warm-up on agility performance in court-sport athletes.

The purpose of this study was to determine the acute effects of heavy resistance exercise on agility performance in court-sport athletes. Five men (age: 20.6 ± 1.9 years; body mass: 79.36 ± 11.74 kg; body height: 1.93 ± 0.09 m) and five women (age 21.2 ± 2.7 years; body mass: 65.8 ± 10.18 kg; body height 1.77 ± 0.08 m) volunteered to participate in the present study. All subjects were NCAA Division II athletes who currently participated in tennis or basketball and all had previous resistance training experience of at least one year. In a counterbalanced design, agility performance during a 10 m shuttle test was assessed following either a dynamic warm-up (DW) or heavy resistance warm-up (HRW) protocol. The HRW protocol consisted of three sets of squats at 50, 60, and 90% of 1-RM. Agility performance was captured using an eight camera motion analysis system and the mechanical variables of stride length, stride frequency, stance time, flight time, average ground reaction force, as well as agility time were recorded. No significant differences were reported for the HRW and DW protocols for any of the mechanical variables (p>0.05), although there was a trend towards the HRW protocol producing faster agility times compared to the control protocol (p = 0.074). Based on the trend towards a significant effect, as well as individual results it is possible that HRW protocols could be used as an acute method to improve agility performance in some court-sport athletes.