Journal of Strength and Conditioning Research最新文献

{"title":"Biomechanical Insights Into Rotary Inertial Devices vs. Traditional Resistance Training in Half-Squats: A Comparative Analysis of Force, Velocity, and Displacement.","authors":"Carlos Galiano, Francisco Javier Nuñez, Stuart McErlain-Naylor, Pablo Floria","doi":"10.1519/JSC.0000000000005073","DOIUrl":"10.1519/JSC.0000000000005073","url":null,"abstract":"<p><strong>Abstract: </strong>Galiano, C, Nuñez, FJ, McErlain-Naylor, S, and Floria, P. Biomechanical insights into rotary inertial devices vs. traditional resistance training in half-squats: a comparative analysis of force, velocity, and displacement. J Strength Cond Res 39(5): 531-539, 2025-Although rotary inertial devices (RIDs) have been used in resistance training for many years, there is still limited knowledge of the specific biomechanics that distinguish them from traditional resistance training (TRT) methods. The aim of this study is to compare the serial data of force, velocity, and displacement over time in half-squats performed with both devices when the intensity is based on the concentric mean propulsive velocity (MPV). A total of 20 experienced subjects completed 3 sets of 6 half-squats using both RID and TRT. To ensure a similar load intensity, the concentric phase was matched according to the MPV. Measurements of vertical ground reaction force (vGRF), velocity, and displacement were taken for each repetition of the half-squat. The results showed that TRT exhibited a higher vGRF than RID during 0-57% of the concentric phase but a lower vGRF during 74-93% ( p < 0.001). Eccentric vGRF was also higher for TRT throughout much of the eccentric phase (0-13%, 38-54%, and 68-100%, p < 0.001). Rotary inertial device demonstrated faster vertical velocity than TRT during 31-52% of the concentric phase and 1-40% of the eccentric phase ( p < 0.001). However, during the latter part of the concentric phase (72-99%), TRT exhibited faster vertical velocity compared with RID. In addition, TRT resulted in a higher vertical position than RID at the end (67-100%) of the concentric phase ( p = 0.036). Coaches should be aware of these biomechanical differences when prescribing resistance training with RID or TRT, as even with similar loads, distinct patterns in vGRF and velocity over time can lead to different effects on the athlete.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"531-539"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143605298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shoulder Internal and External Rotation Strength Assessment in Baseball Pitchers: Normative Data and Reliability.","authors":"Trey D W Job, Matthew R Cross, John B Cronin","doi":"10.1519/JSC.0000000000005072","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005072","url":null,"abstract":"<p><strong>Abstract: </strong>Job, TDW, Cross, MR, and Cronina, JB. Shoulder internal and external rotation strength assessment in baseball pitchers: normative data and reliability. J Strength Cond Res 39(5): e634-e638, 2025-Rotator cuff strength assessments are valuable for monitoring throwing athlete injury and performance status. Portable technology enables \"in-field\" assessment and, therefore, increases utility. The purpose of this study was to quantify the reliability of strain gauge technology for measuring shoulder rotator strength and provide normative strength values for high school and college pitchers. Subjects (n = 15) participated in 3 testing sessions consisting of 5 maximal isometric shoulder internal rotation (IR) and 5 external rotation trials separated by 7 days. Variables of interest included peak force (Fmax), peak torque (Tmax), rate of force development, and rate of torque development. Coefficients of variation ranged from 4.3 to 5.8% for peak values and 16.0-28.5% for rate measures. Intraclass correlation coefficient estimates ranged from 0.79 to 0.89 for peak values, and 0.80-0.91 for rate measures, with IR typically marginally better than ER. Although practitioners need to be mindful of managing error (e.g., through familiarity), peak measures of rotator cuff strength assessed using portable strain gauge are promising for simple field-based monitoring of shoulder health for throwing athletes.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":"39 5","pages":"e634-e638"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143970941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acute Effects of Assisted and Resisted Sprint Training on Subsequent Sprint Performance: A Systematic Review and Meta-Analysis.","authors":"Kai Xu, MingYue Yin, YuMing Zhong, KongYun Huang, YiMeng Xu, Jing Zhou, Ran Wang","doi":"10.1519/JSC.0000000000005087","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005087","url":null,"abstract":"<p><strong>Abstract: </strong>Xu, K, Yin, M, Zhong, Y, Huang, K, Xu, Y, Zhou, J, and Wang, R. Acute effects of assisted and resisted sprint training on subsequent sprint performance: A systematic review and meta-analysis. J Strength Cond Res 39(5): e711-e720, 2025-The aim of the meta-analysis was to determine the acute effects of resisted (RST), assisted (AST), and unresisted (UST) sprint training on sprint performance and to identify the optimal training protocol. A computerized search was conducted in 5 databases, resulting in the inclusion of 23 studies and 395 subjects. The findings indicated that RST acutely improved sprint performance (effect size [ES] -0.20; p < 0.05), while UST (ES = -0.03) and AST (ES = -0.18) did not produce significant improvements (p > 0.05). Subgroup analyses revealed that RST load as a percentage of body mass (%BM) showed the greatest improvement with heavy loads (50-75% BM, ES = -0.40) compared with light (0-19% BM, ES = -0.22), moderate (20-49% BM, ES = -0.21), and very heavy (>75% BM, ES = 0.10) loads. Further analyses indicated that sled pushing (ES = -0.60) was more effective than sled pulling (ES = -0.34) under heavy load RST conditions. Nonlinear meta-regression results demonstrated that sprint performance improvement exhibited an inverted-U relationship with RST load. In addition, heavy load RST and moderate load AST did not disrupt subsequent sprinting technique. In conclusion, only RST acutely improved subsequent sprint performance, whereas AST and UST did not. For optimal results with RST, it is recommended to use 1 set of heavy loads (50-75% BM) for sled pushing for a distance of 15-20 meters, followed by a rest period of 4-8 minutes before performing 0-30 meters of UST.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":"39 5","pages":"e711-e720"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143970905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effects of Repeated-Sprint Training vs. Short-Bout High-Intensity Interval Training on Hamstring Architecture and Physical Fitness.","authors":"Fraser Thurlow, Ryan Timmins, Shaun J McLaren, Bradley Lawton, Nicholas Cowley, Andrew Townshend, Jonathon Weakley","doi":"10.1519/JSC.0000000000005064","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005064","url":null,"abstract":"<p><strong>Abstract: </strong>Thurlow, F, Timmins, R, McLaren, SJ, Lawton, B, Cowley, N, Townshend, A, and Weakley, J. The effects of repeated-sprint training vs. short-bout high-intensity interval training on hamstring architecture and physical fitness. J Strength Cond Res 39(5): e620-e627, 2025-The aim of the study was to quantify and compare the effects of repeated-sprint training (RST) vs. short-bout high-intensity interval training (HIIT) on hamstring architecture and physical fitness in rugby league players. A parallel, 2-group, pretest posttest design was used, whereby 24 representative U20 players were assigned to either RST or short-bout HIIT for a 6-week intervention delivered alongside usual training. Assessments of biceps femoris long-head (BFlh) muscle architecture, countermovement jump (CMJ), eccentric hamstring strength, sprint force-velocity power (FVP) profiles, and 1,200 m shuttle run time (i.e., aerobic fitness) were performed. Compared with baseline, the RST group was associated with moderate improvements in aerobic fitness (change ±90% confidence interval [CI]: -4 ± 5 seconds) and maximal theoretical velocity (0.11 ± 0.10 m·s-1), as well as a moderate increase in BFlh fascicle length (1.05 ± 0.46 cm), a small increase in BFlh muscle thickness (0.12 ± 0.16 cm), and a moderate reduction in the BFlh pennation angle (-0.85 ± 0.64°). The short-bout HIIT group was associated with a moderate improvement in aerobic fitness (-10 ± 4 seconds) and a small improvement in CMJ peak power (1.4 ± 1.4 W·kg-1), as well as a large increase in BFlh fascicle length (0.99 ± 0.44 cm), a moderate increase in BFlh muscle thickness (0.15 ± 0.13 cm), and a small reduction in the BFlh pennation angle (-0.67 ± 0.50°). Changes in aerobic fitness were greater for short-bout HIIT when compared to RST, and this difference was moderate (effect size ±90% CI: 0.89 ± 0.82; pMET 0.108). Conversely, changes in 10-m sprint (0.82 ± 0.66; pMET 0.062), 20-m sprint (0.95 ± 0.71; pMET 0.043), 30-m sprint (0.104 ± 0.73; pMET 0.031) times, and certain FVP characteristics, were greater for RST, and these differences were moderate. Both groups increased fascicle length, but RST was more effective at improving sprint speed, while short-bout HIIT was more effective for improving aerobic fitness. Collectively, our findings demonstrate the potential benefits of these conditioning methods, which may cause morphological, physiological, and neuromuscular adaptations in athletes when applied alongside usual training practice.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":"39 5","pages":"e620-e627"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143989047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Associations Between Maximum Isometric Strength and Weightlifting Performance in Youth Weightlifters.","authors":"Marcos A Soriano, Francisco J Flores, Diego A Alonso-Aubín, Carlos García-Sánchez, Julio A Ceniza-Villacastín, Ester Jiménez-Ormeño, Juan Lama-Arenales, Paul Comfort","doi":"10.1519/JSC.0000000000005052","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005052","url":null,"abstract":"<p><strong>Abstract: </strong>Soriano, MA, Flores, FJ, Alonso-Aubín, DA, García-Sánchez, C, Ceniza-Villacastín, JA, Jiménez-Ormeño, E, Lama-Arenales, J, and Comfort, P. Associations between maximum isometric strength and weightlifting performance in youth weightlifters. J Strength Cond Res 39(5): 570-578, 2025-The aim of this study was to explore the differences between the isometric start position pull (ISPP) and mid-thigh pull (IMTP) peak forces in youth weightlifters and their associations with weightlifting performance. Forty-six male and female youth weightlifters (age: 15.4 ± 1.3 years, height: 1.66 ± 0.91 m, body mass: 65.7 ± 10.0 kg, weightlifting experience: 2.5 ± 1.6 years) participated. Weightlifting performance was evaluated as the sum of the heaviest snatch and clean and jerk. Isometric start position pull and IMTP kinetics were calculated using a force plate. Weightlifting performance, ISPP, and IMTP were evaluated in 3 different sessions and were calculated in absolute, relative, and allometrically scaled forms. Paired samples t-tests were conducted to analyze the differences between the ISPP and IMTP. Pearson's r correlation coefficient was used to determine the relationship between weightlifting performance and the ISPP and IMTP. Fisher's r-z transformation was performed to determine the differences in the magnitude of correlations between the ISPP and IMTP with weightlifting performance. Statistical significance was set at p ≤ 0.05. All subjects had a significantly (p < 0.001) lower performance when performing the ISPP compared with IMTP. Significant (p < 0.001) and strong correlations were found between ISPP and IMTP with weightlifting performance (r = 0.56-0.91). Weightlifting performance was more strongly associated with ISPP than IMTP, although only significant in the relative and allometrically scaled forms (z = 2.19, p = 0.01, z = 2.34, p = 0.01, respectively). The ISPP is highly associated with weightlifting performance in youth weightlifters and should be included in talent identification and development testing batteries.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":"39 5","pages":"570-578"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144004929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intensity of National Collegiate Athletics Association Division I Women's Soccer Regular Season Games.","authors":"Mario Norberto Sevilio De Oliveira Junior, Victor Geovani Soares de Sousa, Jefferson Fernando Coelho Rodrigues Junior, Nilo César Ramos, Jason Cholewa","doi":"10.1519/JSC.0000000000005053","DOIUrl":"10.1519/JSC.0000000000005053","url":null,"abstract":"<p><strong>Abstract: </strong>Sevilio De Oliveira Junior, MN, Soares de Sousa, VG, Coelho Rodrigues, JF, Ramos, NC, and Cholewa, J. Intensity of National Collegiate Athletics Association Division I women's soccer regular season games. J Strength Cond Res 39(5): 602-607, 2025-This study assessed the intensity of National Collegiate Athletics Association Division I women's soccer regular season games. Thirteen regular season games of one team (18 subjects) were analyzed. Data were collected on average intensity, accumulated time per heart rate (HR) zone, and HR behavior throughout each game. The HR zones adopted were as follows: Z1 = 50-59%, Z2 = 60-69%, Z3 = 70-79%, Z = 80-89%, and Z5 = 90-100% of maximum HR (HRmax). One-way analysis of variance (ANOVA) with repeated measures was performed for comparisons between games, by time range, and by HR zone. Two-way ANOVA with repeated measures compared average intensity of each game and high- and low-intensity zones between the first and second half ( p ≤ 0.05). Average intensity of games was 89.08 ± 1.42% of HRmax, with minimum values of 67.12 ± 2.71% and maximum of 97.66 ± 0.98%, corresponding to 176 ± 2.13, 132.88 ± 5.50, and 193.66 ± 1.40 b·min -1 , respectively. There was no significant difference in intensity between games ( p = 0.09). Players spent more time in high-intensity zones Z5 and Z4. The average time in Z5 was 33 minutes 03 seconds ± 2 minutes 45 seconds and in Z4 was 18 minutes 24 seconds ± 2 minutes 34 seconds ( p = 0.252). No significant differences were found in intensity comparisons between first and second half ( p = 0.32) and 15-minute periods ( p = 0.25). The intensity of games was high and constant throughout the 90 minutes in all games. Heart rate monitoring and planned substitutions during matches and training that focus on intermittent high-intensity activities and recovery, such as cold-water immersion may optimize match performance and prevent injuries.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"602-607"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143605238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative Analysis of Elbow Flexor Morphology, Physiology, and Performance Between Arm Wrestlers and Strength-Trained Athletes.","authors":"Francesco Coletta, Leonardo Cesanelli, Sigitas Kamandulis, Daniele Conte","doi":"10.1519/JSC.0000000000005071","DOIUrl":"10.1519/JSC.0000000000005071","url":null,"abstract":"<p><strong>Abstract: </strong>Coletta, F, Cesanelli, L, Kamandulis, S, and Conte, D. Comparative analysis of elbow flexor morphology, physiology, and performance between arm wrestlers and strength-trained athletes. J Strength Cond Res 39(5): 579-586, 2025-This study aims to compare the morphological, performance, and physiological characteristics of the elbow flexors between arm wrestlers and strength-trained athletes. Nine national and international level arm wrestlers (age = 30.5 ± 7.7 years, body mass = 89.4 ± 7.5 kg, stature = 183 ± 7.3 cm, strength training experience = 12.7 ± 8.6 years, arm wrestling training experience = 4.8 ± 2 years) and 9 strength-trained athletes (age = 28.6 ± 4.6 years, body mass = 88.2 ± 15.4 kg, stature = 179.4 ± 5.8 cm, strength training experience = 11.3 ± 8 years) voluntarily participated in the study. Arm and forearm circumferences of the dominant upper limb were measured to assess the anthropometric characteristics. Moreover, morphological evaluations of the biceps brachii muscle and distal tendon thickness were conducted using ultrasound. Peak torque (PT) and rate of force development (RFD) were assessed using 2 elbow flexion maximally voluntary isometric contraction tests (test-1: 3 × 3 seconds; test-2: 3 × 20 seconds). During test-2, biceps brachii oxygenation levels were measured using near-infrared spectroscopy. Arm wrestlers exhibited greater forearm hypertrophy compared with strength-trained athletes ( p = 0.005; effect size [ES] = 1.54; large), whereas no differences ( p > 0.05) were found in arm circumference and biceps brachii muscle and tendon thickness (normalized by muscle thickness). In addition, arm wrestlers showed higher PT in both tests ( p < 0.05; ES = moderate-to-large) and higher RFD only in test-1 ( p < 0.005). Finally, a greater reduction in muscle oxygenation levels ( p = 0.025; ES = 0.277; moderate) was found compared with strength-trained athletes. This study provides insights of the arm wrestlers' physiological and performance characteristics allowing coaches to design appropriate training sessions in this unique sport.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"579-586"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143605360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of 6-Week Vibration vs. Nonvibration Foam Rolling on Performance-Related Physical Fitness Parameters in Young Male Soccer Players: A Randomized Controlled Trial.","authors":"Erhan Secer, Derya Ozer Kaya","doi":"10.1519/JSC.0000000000005062","DOIUrl":"10.1519/JSC.0000000000005062","url":null,"abstract":"<p><strong>Abstract: </strong>Secer, E and Kaya, DO. Effects of 6-week vibration vs. nonvibration foam rolling on performance-related physical fitness parameters in young male soccer players: A randomized controlled trial. J Strength Cond Res 39(5): e647-e658, 2025-The purpose of this study was to examine the effects of 6-week vibration foam rolling (VFR) and nonvibration foam rolling (FR) on performance-related physical fitness parameters in young male soccer players. Thirty-six, volunteer, young, male soccer players (mean age: 15.55 ± 0.55 years) were randomly assigned into 3 groups: a VFR group ( n = 12), a FR group ( n = 12), and a control group (CG) ( n = 12). The players in VFR and FR groups performed VFR or FR interventions thrice per week for 6 weeks (3 × 30 seconds for each muscle or body side). Testing measures included reaction time, assessed with the reaction time measuring device; agility, assessed with the t test; sprint, assessed with the 20-m sprint test; and anaerobic power, assessed with the Wingate anaerobic power test. Dominant lower-extremity reaction time improved in the VFR group when compared with the FR group {-1.93 seconds (95% confidence interval [CI]: -3.07 seconds/-0.78 seconds)} and CG [-2.05 seconds (95% CI: -3.43 seconds/-0.67 seconds)]. Agility improved in the VFR and FR groups when compared with the CG [-0.90 seconds (95% CI: -1.26 seconds/-0.53 seconds), -0.53 seconds (95% CI: -0.95 seconds/-0.11 seconds), respectively]. Sprint improved in the VFR and FR groups when compared with the CG [-0.13 seconds (95% CI: -0.18 seconds/-0.07 seconds), -0.14 seconds (95% CI: -0.21 seconds/-0.06 seconds), respectively]. In conclusion, both 6-week VFR and FR increased agility and sprint performances. Vibration foam rolling is more effective than FR for improving lower-extremity reaction time. Vibration foam rolling and FR could be relevant options for strength and conditioning coaches to improve the physical performance of soccer players.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e647-e658"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143604910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hamstring Muscle Stiffness During Isometric Contractions Until Task Failure in Footballers With and Without Injury History.","authors":"Antonio Martínez-Serrano, Régis Radaelli, Tomás Trindade de Freitas, Pedro Emilio Alcaraz, Sandro Remo Freitas","doi":"10.1519/JSC.0000000000005061","DOIUrl":"10.1519/JSC.0000000000005061","url":null,"abstract":"<p><strong>Abstract: </strong>Martínez-Serrano, A, Radaelli, R, Trindade de Freitas, T, Alcaraz, PE, and Freitas, SR. Hamstring muscle stiffness during isometric contractions until task failure in footballers with and without injury history. J Strength Cond Res 39(5): e659-e667, 2025-Despite various proposed prevention strategies, the incidence of hamstring injuries in modern soccer is still elevated. Recent research has focused on exploring how muscle tissue stiffness behaves under fatigue conditions as a potential risk factor. This study aimed to examine the active stiffness of biceps femoris long head (BFlh) and semitendinosus (ST) muscles using ultrasound-based shear wave elastography (SWE) during a knee flexors' submaximal contraction until exhaustion in highly trained national-level male footballers, comparing previously injured and noninjured limbs. A case-control study was performed including 94 highly trained male footballers. Using SWE, the passive and active stiffness of the BFlh and ST were assessed at rest and during a knee flexors' submaximal isometric contraction at 40% of maximal voluntary isometric contraction (MVIC) until exhaustion. Differences in stiffness patterns between previously injured and noninjured limbs were analyzed, along with passive muscle stiffness, knee flexors' MVIC, and endurance capacity. No statistically significant differences in the active stiffness of BFlh and ST between previously injured and noninjured limbs throughout the contraction task were found ( p > 0.05; 0-100% contraction time). Similarly, there were no statistically significant differences in BFlh (mean difference [mean diff.] = 0.2 kPa; p > 0.05) and ST (mean diff. = 0.9 kPa; p > 0.05) passive stiffness, knee flexors' MVIC (mean diff. = -8.5 Nm; p > 0.05), or time to exhaustion (mean diff. = 6.95 seconds; p > 0.05). Load-sharing between the BFlh and ST did not change significantly throughout the contraction ( p > 0.05; 0-100% contraction time). These results suggest that players with a history of hamstring injuries may retain similar mechanical properties and coordination strategies as noninjured players.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"e659-e667"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143604931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Rapid Weight Loss in Male and Female Wrestlers.","authors":"Andrew D Marten, Michael D Mattin, Mia V Rumps, Shreya M Saraf, Mary K Mulcahey","doi":"10.1519/JSC.0000000000005097","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005097","url":null,"abstract":"<p><strong>Abstract: </strong>Marten, AD, Mattin, MD, Rumps, MV, Saraf, SM, and Mulcahey, MK. Effects of rapid weight loss in male and female wrestlers. J Strength Cond Res 39(5): e721-e729, 2025-The long-standing practice of rapid weight loss (RWL) of wrestlers and other combat athletes is known as \"cutting weight.\" This practice often consists of rapid dehydration and malnutrition to \"weigh-in\" at a lower weight class for competition. There are multiple negative nutritional and psychological implications in wrestlers because of cutting weight including significantly increased risk of athletic injury, decreased serum testosterone and increased serum cortisol, as well as an increased risk of eating disorders and hormone fluctuations in female athletes. In addition, literature suggests a decrease in athletic performance for athletes undergoing >5% RWL. The purpose of this narrative review was to provide an overview of the implications of weight cutting on athletic performance and overall well-being, and to highlight specific medical, physiological, and psychological effects in male and female wrestlers to aid healthcare workers in making recommendations regarding weight cutting practices.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":"39 5","pages":"e721-e729"},"PeriodicalIF":2.5,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144026993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}