Collegiate Soccer Research Articles

The influence of menstrual cycle phase on isokinetic knee flexor and extensor strength in female soccer players: a pilot study

ABSTRACT The prevalence of anterior cruciate ligament injury in female soccer players has been attributed to hormonal fluctuations during the menstrual cycle (MC), with injury incidence greatest during the follicular phase. Eight, eumenorrheic, collegiate soccer players (19.5 ± 0.75 years, 1.62 ± 4.90 cm, 61.12 ± 7.6 kg mean ± SD) completed eccentric knee flexor and concentric knee extensor trials at 60 and 240°·s−1 during the follicular, ovulation and luteal phases of their MC. Peak torque and corresponding angle of peak torque were maintained across all phases of the MC, irrespective of testing modality and speed (p ≥ 0.149). Strength ratios defined using peak torque were also not sensitive to MC phase (p ≥ 0.933). However, Functional Range in eccentric knee flexion was significantly lower during the follicular phase (p = 0.017), at both testing speeds. This supports epidemiological observations but highlights the importance of analysing isokinetic data beyond the peak of the strength curve. Interpretation of isokinetic data should therefore focus on points of “weakness” as opposed to maximum strength, whilst (p)rehabilitative strategies should consider strength through range of motion, and at different speeds. Eccentric hamstring strength was observed to decrease significantly at the higher speed, contrary to observations in elite male players, and potentially reflecting a differential training adaptation.

The Accuracy of the Titan 1+ 10 Hz Global Positioning System for Measures of Time, Distance, and Top Speed

Introduction: Global Positioning System (GPS) technology provide quantifiable data concerning the number and types of movements athletes complete across training session and match player. The Titan 1+ is a novel GPS device that has not been investigated to establish measures of accuracy or reliability. The purpose of this study was to establish device accuracy for metrics including distance, top speed, and time between the Titan 1+ 10 Hz GPS device and criterion measures. Criterion measures include tape measure, stopwatch, and radar gun for measures of distance, time, and top speed, respectively. Methods and Materials: 16 male NCAA collegiate soccer players completed running protocols of varying distances and speeds, including long and short duration straight-line running (100m Run and SLR), tight and gradual change of direction running (COD T and COD G), and a team-sport simulated circuit. Results: The Titan 1+ was not significantly different from tape measured distance during the SLR protocol for 10m jog and all movements speed across 20m and 40m (p < .05). The Titan 1+ was significantly correlated to radar gun top speed measures for all distances and movement speeds during the SLR (p < .01). The Titan 1+ was significantly different from the stopwatch for measures of time accuracy (p < .0001), however significant correlations were identified for all jogging distances (p < .01), the 20m and 40m strides (p < .01), and the 10m sprint (p < .01). COD G and COD T distances were accurately measured between the Titan 1+ and tape measure (p < .05). The Titan 1+ revealed correlations for time measures during jogging and striding during the COD G (p = .001 and p < .0001) and during the COD T (p < .0001 and p< .0001). Device accuracy was established for measure of time during the TSSC (p < .05), with time measures significantly correlated between the Titan 1+ and stopwatch (p < .01). Top speed for the TSSC was significantly different between the radar gun and Titan 1+ device (p = .001), but both devices were significantly correlated (p < .01). Conclusions: The results of the present study indicate that the Titan 1+ demonstrates accurate measures of time, distance, and top speed when compared to criterion measures.

Less Total-Body Fat and Lower-Extremity Fat Are Associated with More High-Intensity Running during Games in Female University Soccer Players

This study examined the relationship between body composition and on-field, in-game physical performance in female collegiate soccer players. Body composition, including total mass, fat mass, and lean tissue mass for the lower extremities and total body, was measured in 10 starting players using dual energy x-ray absorptiometry (DXA). On-field, in-game physical performance was tracked via a global positioning system (GPS) over 14 regular-season games, measuring total distance and distance covered in six speed zones. Players covered 4544.7 ± 495.2 m in the first half of the game and significantly less distance in the second half (3356.5 ± 1211.7 m, p = 0.004). A repeated measures ANOVA revealed decreased distances in jogging, low-, and moderate-intensity running during the second half compared to the first half of the game (p < 0.001). Lower total-body fat mass, total-body fat percentage, and lower-extremities fat mass were correlated with greater distances at moderate- and high-intensity running during the second half and entire game (r values from −0.644 to −0.745, p < 0.01 to 0.04). These findings suggest that body composition can influence the distance covered at moderate- and high-intensity running speed during competitive games. Training strategies aimed at reducing fat mass and incorporating high-intensity training may benefit female soccer players and enhance team success.

Female Collegiate Soccer Player With Atypical Healing Following ACL Reconstruction: A Level 3 Case Study

Female Collegiate Soccer Player With Atypical Healing Following ACL Reconstruction: A Level 3 Case Study

Eversion Force Control and Neural Drive to the Peroneus Muscles in Male Collegiate Soccer Athletes With and Without Perceived Ankle Instability

OBJECTIVE: To investigate whether individuals with perceived ankle instability (PAI) exhibited lower force control capacity and higher neural drive variability during ankle eversion force control tests compared to individuals without PAI. DESIGN: Cross-sectional case-control study. METHODS: We included male collegiate soccer athletes with ( n = 16) and without PAI ( n = 11). Force steadiness and accuracy tests were performed at 10%, 30%, and 50% of maximal voluntary contraction. Neural drive to the peroneal muscles was calculated using high-density surface electromyography. We analyzed force error, force complexity, and force and neural drive variability. RESULTS: Eversion strength was higher in the PAI group (0.36 ± 0.1 N m/kg) ( P = .03). Force error (mean difference [MD], 0.05; 95% confidence interval [CI]: −0.31, 0.21), force complexity (approximate entropy) (MD, 0.08; 95% CI: − 0.34, 0.50), force (MD, 0.20; 95% CI: −1.77, 1.36), and neural drive (MD, 1.75; 95% CI: −2.48, 5.91) variability at 10% maximal voluntary contraction did not differ between groups ( P>.05). There were no significant differences between groups in other intensities and variables ( P>.05). CONCLUSION: Eversion force control and neural drive to the peroneal muscles in male collegiate soccer athletes with PAI did not differ from those in athletes without PAI. JOSPT Open 2024;2(4):315-321. Epub 15 July 2024. doi:10.2519/josptopen.2024.0360

Relationship between fat-free mass index and nutrient intake in protein supplement user among Japanese collegiate soccer athletes.

Protein supplements are widely used by athletes, prompting the scrutiny of their impact on low energy availability. This study investigated whether habitual protein supplement use is linked to physical characteristics and nutrient intake in Japanese university soccer athletes. In addition, an attempt was made to examine the differences in physical characteristics and nutrient intake according to muscle mass in protein supplement users using the fat-free mass index (FFMI), which reflects muscle mass. A dietary survey, physical activity survey, and measurement of the physical characteristics of 38 Japanese collegiate soccer players were conducted. The habitual protein supplement utilization rate among the participants was 50%, and the participants exhibited an FFMI of 19.2 ± 1.3 kg/m2. Significant disparities between the two groups were noted in exercise energy expenditure (p = 0.023); carbohydrates (p = 0.039); copper (p = 0.003); and vitamins B1 (p = 0.016), B2 (p = 0.040), B6 (p = 0.003), C (p = 0.012), and D (p = 0.033), with higher levels observed in the protein-consuming cohort compared to the non-consuming cohort. Protein supplement users (n = 15) were stratified into two groups based on the median FFMI of the entire population (18.9 kg/m2). While the energy balance ratios were comparable between the groups, the high FFMI group tended to exhibit elevated energy intake (p = 0.169), consumption (p = 0.076), and carbohydrate consumption (p = 0.092), compared to the low FFMI group. These findings suggest that adequate carbohydrate and protein intakes are crucial for preserving or augmenting muscle mass in young Japanese soccer athletes, including those consuming protein supplements.

Impressions of an Electrolyte Hydration Beverage among Individuals Participating in Collegiate Soccer

Impressions of an Electrolyte Hydration Beverage among Individuals Participating in Collegiate Soccer

Classification of movements of collegiate female soccer players using inertial measurement units

This study aimed to classify the movements of female soccer players during matches using raw data measured by inertial measurement units (IMUs). Twelve collegiate female soccer players were equipped with IMUs (100 Hz), and raw triaxial acceleration data from eight official matches were analyzed. The measurement data were separated every 3 s, and a Fast Fourier Transform (FFT) was performed. After FFT, the Euclidean distances between the data when the players were in the stationary state and other states were calculated to classify the movements of the players using the k-means method. The data of the clustering numbers classified as the stationary state were eliminated after analyzing the movements of players by video filming the matches. After classification, the average Euclidean distances between the stationary state and other movements were calculated. Consequently, the results showed that the upward and downward directions of the raw data affected the classification. Using the methods of this study, it was also shown that the distribution of Euclidean distances differed from player to player. Our findings indicate that the method used in this study can be used to classify and characterize the movements of female collegiate soccer players.

Seasonal Changes in Match Demands and Workload Distribution in Collegiate Soccer Across Two Seasons.

Floersch, S, Vidden, C, Askow, AT, Jones, MT, Fields, JB, and Jagim, AR. Seasonal changes in match demands and workload distribution in collegiate soccer across two seasons. J Strength Cond Res 38(8): 1440-1446, 2024-The purpose of this study was to examine seasonal changes in match demands in a collegiate women's soccer team. Forty-eight NCAA Division III women soccer athletes (age: 19.5 ± 1.2 years; height: 1.67 ± 0.05 m; body mass: 64.8 ± 7.4 kg; fat-free mass: 50.0 ± 4.5 kg; body fat %: 22.6 ± 6.0) were equipped with wearable global positioning systems with inertial sensors and heart rate (HR) monitors during matches throughout the 2019 (n = 22) and 2021 seasons (n = 26). Players were classified by position: flank player (FP; n = 28), center midfielder (CM; n = 11), and center back fielder (CB; n = 9) and as starters (S, n = 17) or reserves (R, n = 31). Variables included HR, training load, total distance, high-speed distance, distance per minute, and weighted distance. Differences in match and practice session demands were analyzed using linear mixed-effects models with season (2 levels; 2019 and 2021) as a fixed factor, with alpha set to p = 0.05. Data across all matches and training sessions were collapsed and presented as mean ± SD for descriptive purposes and then grouped by session type (i.e., match or training) and position. Athletes traveled more distance at high speeds during match play in the 2021 season compared with 2019 (mean difference, 95% confidence intervals [CI]) (200, 95% CI: 104, 304 km; p < 0.05) but had a lower training load in 2021 compared with 2019 (-50, 95% CI: -63, -36; p < 0.05) during match play. For training sessions, mean HR (4, 95% CI: 2, 5 bpm), total distance (0.5, 95% CI: 0.4, 0.7), distance per minute (5.6, 95% CI: 4.5, 6.7 m·min-1), high-speed distance (43, 95% CI: 43, 18, 67 m), high accelerations (8.6, 95% CI: 5.4, 11.8 n), and high accelerations per minute (0.1, 95% CI: 0.1, 0.1 n·min-1) were all higher in 2021 compared with 2019 (p < 0.05). As a team, several differences in measures of external workload were found between seasons in both session types (training and matches). Variations in positional demands of match play appear to fluctuate by year.

Relationship between Workload, Psychological State and Recovery in Female Soccer Athletes.

This study assessed the multifaceted relations between measures of workload, psychological state, and recovery throughout an entire soccer season in female collegiate soccer athletes (19.8±1.2 yrs, 132±12.3 lbs, 63±3.2 in). A prospective longitudinal study was utilized to measure workload (GPS training load, Rate of Perceived Exertion (RPE), psychological state (mental stress, mental fatigue, and mood), and recovery (sleep duration, sleep quality, and soreness), during 90 observations (59 training sessions and 21 games). Separate linear-mixed effect models were used to assess outcomes of RPE, soreness, and sleep duration. A linear mixed-effects model explained 59% of the variance in RPE following each session. Specifically, each standard deviation increase in GPS load and mental stress in the morning prior to training increased RPE by 1.46 (SE=0.08) and 0.29 (SE=0.07), respectively, following that day's training. Furthermore, a significant interaction was found between several predictor variables and chronological day in the season while predicting RPE. Specifically, for each standard deviation increase in GPS load, RPE went up by 0.0055 per day during the season suggesting that load had a higher impact on RPE as the season progressed. In contrast, the interaction of day by mental stress, sleep duration, and soreness continued to be stronger as the season progressed. Each linear mixed-effect model predicted a larger amount of variance when accounting for individual variations in the random effects.

Sex Differences in Physiological Responses to a National Collegiate Athletic Association Division I Soccer Season.

McFadden, BA, Walker, AJ, Cintineo, HP, Bozzini, BN, Sanders, DJ, Chandler, AJ, and Arent, SM. Sex differences in physiological responses to a national collegiate athletic association division I soccer season. J Strength Cond Res XX(X): 000-000, 2024-Identifying physiological changes that occur in response to workload demands can help to elucidate athlete management and recovery strategies. The purpose of this study was to compare the physical and physiological demands between men and women throughout the course of a collegiate soccer season. Men (N = 23) and women (N = 26) soccer players participated in blood draws before preseason (T1) and every 4 weeks thereafter (T2-T4). Workload was determined at all practices and games via heart rate and global positioning satellite monitoring systems. Repeated measures multivariate analysis of variance and linear mixed models were used to assess workload and biomarker responses throughout the season (p < 0.05). Both teams experienced the highest workloads during the first 4 weeks of the season (p < 0.05), which was followed by several biomarker perturbations. Sex-by-Time interactions were observed for total cortisol, growth hormone, insulin-like growth factor-1, thyroxine, thyroid-stimulating hormone, vitamin D, and omega 3 fatty acid index (p < 0.05). Additional Sex effects were observed for free and total testosterone, estrogen, prolactin, sex-hormone binding globulin, creatine kinase, and iron levels (p < 0.05). Women soccer players experienced further Time effects for free cortisol, iron, ferritin, and percent transferrin saturation (p < 0.05). Male soccer players experienced additional Time effects for total testosterone, estrogen, creatine kinase, interleukin-6, triiodothyronine, and ferritin (p < 0.05). Despite similar patterns of change in workloads, differential fluctuations in physiological markers were observed between the sexes. Understanding sex differences in response to comparable workloads may enhance exercise prescriptions for better athlete management plans. Additional strategies to increase iron may be warranted in female athletes.

Snooze it or Lose it: Understanding Sleep Disturbance and Injuries in Soccer and Basketball Student-Athletes.

To assess the sleep characteristics of collegiate soccer and basketball student-athletes and explore the associations between sleep and injury risk. Cohort study. NCAA D1 and NAIA Tier 1. One hundred eighty-one collegiate soccer and basketball student-athletes (42% female; mean age: 20.0 ± 1.7 years). Questionnaires were administered during the 2020/2021 and 2021/2022 preseason, collecting demographic, injury history, medical history, and sleep information, including sleep difficulty category scores of 0 to 4 (none), 5 to 7 (mild), and ≥8 (moderate/severe) and other sleep disturbance measures derived from the Athlete Sleep Screening Questionnaire (ASSQ), including insufficient sleep duration (<7 hours of sleep) and poor subjective sleep quality. All-complaint knee and ankle injuries. According to the ASSQ, 25.4% (95% confidence interval [CI], 17.9-34.3) of the student-athletes had mild sleep difficulty and 12.7% (95% CI, 7.3-20.1) had moderate/severe sleep difficulty. 36.1% (95% CI, 29.1-43.6) had insufficient sleep duration. 17.1% (95% CI, 11.7-23.7) were not satisfied with the quality of their sleep (poor sleep quality), and 13.8% (95% CI, 9.1-19.7) had an "eveningness" chronotype. Based on multivariable logistic regression models, student-athletes with poor sleep quality had significantly higher odds for injury (OR: 2.2, 95% CI, 1.04-4.79, P = 0.039). Clinically relevant dysfunctional sleep patterns are prevalent among collegiate soccer and basketball student-athletes. Poor sleep quality was significantly associated with injury risk among student-athletes. Findings suggest a substantial sleep problem in collegiate soccer and basketball student-athletes and warrant that student-athletes are regularly screened and timely interventions applied.

Neural Mechanisms Associated With Postural Control in Collegiate Soccer and Non-Soccer Athletes.

Sport-specific training may improve postural control, while repetitive head acceleration events (RHAEs) may compromise it. Understanding the neural mechanisms underlying postural control may contextualize changes due to training and RHAE. The goal of this study was to determine whether postural sway during the Balance Error Scoring System (BESS) is related to white matter organization (WMO) in collegiate athletes. Collegiate soccer ( N =33) and non-soccer athletes ( N =44) completed BESS and diffusion tensor imaging. Postural sway during each BESS stance, fractional anisotropy (FA), and mean diffusivity (MD) were extracted for each participant. Partial least squares analyses determined group differences in postural sway and WMO and the relationship between postural sway and WMO in soccer and non-soccer athletes separately. Soccer athletes displayed better performance during BESS 6, with lower FA and higher MD in the medial lemniscus (ML) and inferior cerebellar peduncle (ICP), compared to non-soccer athletes. In soccer athletes, lower sway during BESS 2, 5, and 6 was associated with higher FA and lower MD in the corticospinal tract, ML, and ICP. In non-soccer athletes, lower sway during BESS 2 and 4 was associated with higher FA and lower MD in the ML and ICP. BESS 1 was associated with higher FA, and BESS 3 was associated with lower MD in the same tracts in non-soccer athletes. Soccer and non-soccer athletes showed unique relationships between sway and WMO, suggesting that sport-specific exposures are partly responsible for changes in neurological structure and accompanying postural control performance and should be considered when evaluating postural control after injury.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content, available at: http://links.lww.com/JNPT/A472 ).

The 11+ injury prevention programme decreases rate of hamstring strain injuries in male collegiate soccer players

ObjectivesTo investigate if the 11+ injury prevention programme decreases the risk of hamstring injury and improves recovery time and determine whether compliance with the 11+ affects hamstring injury risk.MethodsThis study...

Sex Differences in Wellness Scores in Collegiate Athletes

Subjective wellness scores reflect athlete responses to training, fatigue, personal experiences, and recovery, and evidence suggests these scores may differ between athletes based on sex. This study aimed to evaluate the differences in daily wellness scores between sexes in collegiate soccer, swimming, and basketball athletes. Athletes (n = 294, 63% female) completed daily wellness surveys for energy, health status, mood, muscle readiness, sleep quality, sleep duration, stress, diet, and overall wellness. Variables were evaluated on a 5-point Likert scale, except sleep duration, quantified in hours. Repeated measures, mixed linear models, repeated measures, and ordinal logistic models were used to assess sex differences in wellness outcomes. In basketball, females have 0.30 times the odds (95% CI 0.19, 0.48) of males of a worse health status score. For soccer, females have 2.45 times the odds (95% CI 1.32, 4.44) of males with a worse stress wellness score. In swimming, females, on average, slept 0.40 more hours of sleep per night (95% CI 0.02, 0.79) as compared to males. These data suggest that differences in wellness subcomponents are nuanced by sport. This information can be used to provide targeted programming for athletes to improve wellness and reduce stress, which may subsequently enhance mental health, academic performance, and sports performance.

Effects of plyometric training on heading jump performance and motion in collegiate soccer players

Effects of plyometric training on heading jump performance and motion in collegiate soccer players

Residual Effects of Same Day Lower Extremity Strength Training on Countermovement Jump Performance in Collegiate Women Athletes.

Balancing of strength programming intensity with sport demands is necessary to avoid excessive workloads that could inhibit performance. To expand previous jump height focused literature, this study evaluated whether countermovement jump (CMJ) movement strategies, including eccentric characteristics, might reveal CMJ execution strategy shifts to achieve similar afternoon CMJ height following a morning resistance training session (RTS). Fifteen collegiate women's soccer and volleyball athletes (18-24 years, 73.6 ± 8.4 kg, 1.74 ± 0.19 m) participating in an offseason RTS completed five CMJs during two afternoon sessions (48 h apart), one 4-6 h post morning RTS, and one on a rest day. The RTS consisted of 2 sets of 10 repetitions at 70-80% 1RM for the back squat, the front squat, and the forward lunge. Vertical ground reaction forces were recorded from which 13 outcome measures describing elements of the eccentric and concentric CMJ phases were computed. No significant differences in jump height (p = 0.427, d = 0.17) or outcome measures (p = 0.091-0.777, d = -0.07-0.21) between sessions with exception of a significant concentric phase time decrease (p = 0.026, d = 0.23) following the RTS were identified. Given the magnitude of the mean concentric phase time change (0.01 s), the result likely has limited practical meaning. As these results confirm previous CMJ height literature, practitioners have further evidence that a morning RTS does not interfere or enhance afternoon CMJ performance in athletic women.

Mechanisms of Injury Leading to Concussions in Collegiate Soccer Players: A CARE Consortium Study

Background: Few previous studies have investigated how different injury mechanisms leading to sport-related concussion (SRC) in soccer may affect outcomes. Purpose: To describe injury mechanisms and evaluate injury mechanisms as predictors of symptom severity, return to play (RTP) initiation, and unrestricted RTP (URTP) in a cohort of collegiate soccer players. Study Design: Cohort study; Level of evidence, 2. Methods: The Concussion Assessment, Research and Education (CARE) Consortium database was used. The mechanism of injury was categorized into head-to-ball, head-to-head, head-to-body, and head-to-ground/equipment. Baseline/acute injury characteristics—including Sports Concussion Assessment Tool–3 total symptom severity (TSS), loss of consciousness (LOC), and altered mental status (AMS); descriptive data; and recovery (RTP and URTP)—were compared. Multivariable regression and Weibull models were used to assess the predictive value of the mechanism of injury on TSS and RTP/URTP, respectively. Results: Among 391 soccer SRCs, 32.7% were attributed to a head-to-ball mechanism, 27.9% to a head-to-body mechanism, 21.7% to a head-to-head mechanism, and 17.6% to a head-to-ground/equipment mechanism. Event type was significantly associated with injury mechanism [χ2(3) = 63; P < .001), such that more head-to-ball concussions occurred in practice sessions (n = 92 [51.1%] vs n = 36 [17.1%]) and more head-to-head (n = 65 [30.8%] vs n = 20 [11.1]) and head-to-body (n = 76 [36%] vs n = 33 [18.3%]) concussions occurred in competition. The primary position was significantly associated with injury mechanism [χ2(3) = 24; P < .004], with goalkeepers having no SRCs from the head-to-head mechanism (n = 0 [0%]) and forward players having the least head-to-body mechanism (n = 15 [19.2%]). LOC was also associated with injury mechanism (P = .034), with LOC being most prevalent in head-to-ground/equipment. Finally, AMS was most prevalent in head-to-ball (n = 54 [34.2%]) and head-to-body (n = 48 [30.4%]) mechanisms [χ2(3) = 9; P = .029]. In our multivariable models, the mechanism was not a predictor of TSS or RTP; however, it was associated with URTP (P = .044), with head-to-equipment/ground injuries resulting in the shortest mean number of days (14 ± 9.1 days) to URTP and the head-to-ball mechanism the longest (18.6 ± 21.6 days). Conclusion: The mechanism of injury differed by event type and primary position, and LOC and AMS were different across mechanisms. Even though the mechanism of injury was not a significant predictor of acute symptom burden or time until RTP initiation, those with head-to-equipment/ground injuries spent the shortest time until URTP, and those with head-to-ball injuries had the longest time until URTP.

Variability in Limb Occlusion Pressures Across Visits and Between Limbs in Collegiate Soccer and Cross Country Athletes

Variability in Limb Occlusion Pressures Across Visits and Between Limbs in Collegiate Soccer and Cross Country Athletes

Eccentric Hamstring Strength Imbalance among Football and Soccer Athletes.

Hamstring strain injuries (HSI) are common among football and soccer athletes. Eccentric strength imbalance is considered a contributing factor for HSI. There is, however, a paucity of data on hamstring imbalances of soccer and American football athletes as they age and advance in skill level. High school athletes will display greater interlimb discrepancies compared with collegiate and professional athletes. In addition, soccer athletes will exhibit greater hamstring asymmetry than American football athletes. Hamstring testing was performed on soccer and American football athletes using the NordBord Hamstring Testing System (Vald Performance, Albion, Australia). Age, sex, weight, sport specialization, and sport level were recorded. Maximum hamstring forces (N), torque (N · m), and work (N · s) were measured. Hamstring imbalance (%) was calculated by dividing the absolute value of the difference in leg forces divided by their sum. One-way analysis of variance and independent sample t tests compared measurements between athlete groups. A total of 631 athletes completed measurements, including 88 high school male soccer, 25 college male soccer, 23 professional male soccer, 83 high school female soccer, 28 college female soccer, 288 high school football, and 96 college football athletes. High school soccer players displayed significantly greater imbalances for torque (P = 0.03) and work (P < 0.01) than football athletes. Imbalances for maximum force (P = 0.035), torque (P = 0.018), and work (P = 0.033) were significantly higher for male soccer athletes in high school compared with college- and professional-level athletes. Female high school soccer players had significantly higher imbalance in torque (P = 0.045) and work (P = 0.001) compared with female collegiate soccer players. Football athletes did not experience significant changes in force imbalances between skill levels. High school soccer athletes exhibit greater hamstring imbalances than football athletes. Higher levels of play in soccer, for both male and female athletes, correlate with less hamstring asymmetry.