Journal of Strength and Conditioning Research最新文献

{"title":"Beta-Alanine Supplementation Improves Isotonic Strength Endurance Performance Without Altering Psychological Responses During Drop-Set and Bi-Set Resistance Exercises in Resistance-Trained Individuals.","authors":"Cecilia L Colini, Emerson L Teixeira, Leonardo V Andreato, Déborah C Marques, Braulio H M Branco, Vitor de Salles Painelli","doi":"10.1519/JSC.0000000000005500","DOIUrl":"10.1519/JSC.0000000000005500","url":null,"abstract":"<p><strong>Abstract: </strong>The ergogenic effects of beta-alanine (BA) supplementation are widely recognized, yet its effects on resistance exercises remain uncertain. It is possible that previous protocols were not sufficiently 'acidotic,' such as advanced drop-set and bi-set training systems. This study investigated whether BA supplementation improves isotonic strength endurance performance and psychological responses (perceived exertion, motivation, affect) during drop-set and bi-set protocols. In a double-blind parallel-group design, 22 young resistance-trained men and women were randomly assigned to either a BA group (6.4 g·day -1 , n = 12) or a placebo (maltodextrin, n = 10). After familiarization with psychological scales, maximal strength (1-RM), and strength endurance tests, subjects' total number of repetitions and psychological responses were recorded during drop-set (three sets at 80% 1-RM, with 3 successive 20% load reductions) and bi-set (three sets at 70% 1-RM, consisting of inclined bench press followed by flat bench press) protocols before and after a 4-week supplementation period. Outcomes were analyzed using mixed models for repeated measures ( p < 0.05). The total number of repetitions increased with BA in the drop-set (+17.3%, effect size [ES] = 0.74, p = 0.007) and bi-set (+18.2%, ES = 0.98, p < 0.0001) protocols, but not with placebo (respectively, -0.98%, ES = -0.06, p = 0.988; and +5.6%, ES = 0.01, p = 0.406). Perceived exertion increased across sets during drop-set and bi-set protocols (both p < 0.0001), but without between-group differences (both p > 0.05). Other psychological responses were not influenced by set, group, or time (all p > 0.05). Four weeks of BA supplementation enhanced isotonic strength endurance performance in trained individuals performing drop-set and bi-set resistance protocols, without concurrent change in psychological responses.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"1245-1252"},"PeriodicalIF":3.0,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148405019","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":"Compression Garments and Adaptations to Plyometric Training in Soccer Players: A Randomized-Controlled Study.","authors":"Marius Gosset, Alexis Coquart, Benoit Delaval, Jonathan Catalano, Guillaume Huou, Matthieu Boufflers, Dogkan Bozok, Lucien Bellanger, Tom Douchet, Patrick Viroux, Christelle Jaffré, Abd-Elbasset Abaïdia","doi":"10.1519/JSC.0000000000005489","DOIUrl":"10.1519/JSC.0000000000005489","url":null,"abstract":"<p><strong>Abstract: </strong>The aim of this study was to analyze the effects of the chronic use of compression garments (CG) during a 6-week plyometric microcycle training block on training adaptations in soccer players. It was hypothesized that CG would have a beneficial effect on training adaptations, compared with placebo (PLA). Eighteen male soccer players (19.54 ± 1.39 years; 180.45 ± 5.25 cm; 71.14 ± 6.73 kg) from a reserve team of an elite professional club were randomly assigned to receive either CG or PLA for 24 hours after each plyometric session. The players participated in a plyometric training program: 2 sessions per week for 6 weeks. In a fully rested state, the players were tested before and after the training program on the following parameters: countermovement jump performance, One-leg sprint power, knee extensor strength, pennation angle of the calf muscles, creatine kinase levels, and perceived muscle soreness. The results were analyzed using a 2-factor mixed linear model. Countermovement jump performance showed a moderate, significant improvement in the CG group ( d = 0.762), and a small, nonsignificant improvement in the PLA group ( d = 0.344). One-leg power performance showed a large, significant improvement in the CG group ( d = 1.690) and in the PLA group ( d = 0.867). The results of this study show that the chronic use of CG for recovery does not negatively affect training adaptations and may improve power following a plyometric training program.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":"1259-1270"},"PeriodicalIF":3.0,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148211671","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":"Changes in Strength and Muscle Thickness in Physically Active Males and Females in Response to Resistance Exercise Training: Comparison of Absolute and Relative Change Scores.","authors":"Steven Smith, Fearghal P Behan, David Nolan, Brendan Egan","doi":"10.1519/JSC.0000000000005640","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005640","url":null,"abstract":"<p><strong>Abstract: </strong>Smith, S, Behan, FP, Nolan, D, and Egan, B. Changes in strength and muscle thickness in physically active males and females in response to resistance exercise training: Comparison of absolute and relative change scores. J Strength Cond Res XX(X): 000-000, 2026-Investigations of between-sex differences in adaptive responses to resistance exercise training (RET) have produced equivocal results, some of which may be influenced by the statistical analyses used. This study explored whether different approaches to the analysis of change scores, and accounting for baseline differences, resulted in divergent conclusions about between-sex differences in response to RET. In a parallel group pre-post design, male subjects (n = 22; age, 29.0 ± 6.3 years; body mass index, 25.6 ± 4.0 kg·m-2; body fat, 14.0 ± 5.3%) and female subjects (n = 19; 30.6 ± 6.0 years; 24.9 ± 3.1 kg·m-2; 26.3 ± 5.8%) with >1 year of RET experience completed 12 weeks of twice weekly supervised, periodized, and progressive RET. Strength (kg) was assessed by one-repetition maximum, and muscle thickness (cm) was assessed by two-dimensional ultrasound measurement. Change scores were analyzed as relative change, as absolute change, and as change scores adjusted for baseline differences using analysis of covariance. Muscle thickness of both the biceps brachii (∼14%) and vastus lateralis (∼10%) muscles increased with RET, but no statistically significant differences between groups were observed. The increase in bench press strength was larger in female subjects (32.8 [26.4, 39.2] % vs. 19.9 [15.1, 24.7] %; p = 0.002 d = 1.07) when reported in relative, but not absolute, terms. The increase in hex bar deadlift strength was larger in male subjects (29.4 [21.8, 37.0] kg vs. 14.4 [10.8, 17.9] kg; p < 0.001 d = 1.15) when reported in absolute, but not relative, terms. Physiological differences between sexes that are linked to mechanisms of adaptation are likely to contribute, but which analytical approaches have been applied should be carefully considered when interpreting such observations.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149111346","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":"Weekly External Load in Italian Women's Football Players: Influence of Playing Time.","authors":"Marco Panascì, Vincenzo Rago, Vittoria Ferrando, Carlo Castagna, Piero Ruggeri, Emanuela Faelli","doi":"10.1519/JSC.0000000000005582","DOIUrl":"10.1519/JSC.0000000000005582","url":null,"abstract":"<p><strong>Abstract: </strong>Panascì, M, Rago, V, Ferrando, V, Castagna, C, Ruggeri, P, and Faelli, E. Weekly External Load in Italian Women's Football Players: Influence of Playing Time. J Strength Cond Res XX(X): 000-000, 2026-This study compared external load distribution during the first round of the season between starters (ST) and nonstarters (NS) in Italian professional women's football players. Subjects were 18 players (age: 24.3 ± 3.9 years; height: 167 ± 4.2 cm; body mass: 60.4 ± 5.4 kg) from the same team. External load was measured using global positioning system technology. Variables included total distance (TD), high-speed running distance (19.8-25.2 km·h -1 ), sprint distance (>25.2 km·h -1 ), and the number of accelerations (ACC; >3.0 m·s -2 ) and decelerations (DEC; <-3.0 m·s -2 ). Nine players were classified as ST, defined as those who played at least 60 minutes in 3 consecutive matches during this phase of the season, whereas the remaining 9 players were classified as NS. Results revealed that NS had significantly higher values of TD ( p = 0.001), high-speed running ( p = 0.002), ACC ( p < 0.001), and DEC ( p < 0.001) on MD+2 compared with ST. In addition, NS exhibited significantly greater values of TD ( p = 0.003), ACC ( p = 0.035), and DEC ( p = 0.006) on MD-4 compared with ST. No significant differences were observed between groups on MD-3, MD-2, and MD-1. These findings suggest that NS experienced higher external training loads on MD-4 and MD+2, possibly reflecting compensatory training loads because of limited or no match participation.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148520418","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 Flying Phase in Sprint Runners: Exploring Biomechanical Factors Associated With Performance.","authors":"Sara Faggian, Ling Wei Lei, Emma Ghezzo, Marco Bucciol, Marco Airale, Mario Del Giudice, Samira G Breban, Matteo Bozzato, Isacco Costa, Andrea G Cutti, Nicola Petrone, Giuseppe Marcolin","doi":"10.1519/JSC.0000000000005656","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005656","url":null,"abstract":"<p><strong>Abstract: </strong>Faggian, S, Lei, LW, Ghezzo, E, Bucciol, M, Airale, M, Del Giudice, M, Breban, SG, Bozzato, M, Costa, I, Cutti, AG, Petrone, N, and Marcolin, G. The flying phase in sprint runners: Exploring biomechanical factors associated with performance. J Strength Cond Res XX(X): 000-000, 2026-Biomechanical parameters of sprint performance are intertwined, yet no single variable has been clearly linked to performance. Moreover, existing training guidelines largely rely on the practical experience of world-leading coaches. This study examined the contribution of biomechanical parameters used by high-level sprint coaches to flying-phase performance and season's best running time (SBRT). Eighteen male sprinters performed all-out 60-m sprints on a track instrumented with a 10-camera motion-capture system and 7 embedded force platforms. Parameters recorded between 30 and 50 m were grouped into 4 categories: temporal (swing and contact time), spatial (step and stride length, hip displacement), kinematic (sagittal absolute angle of thigh, shank, and ankle at maximum knee height; push angle at foot-off; support angle at midstance), and kinetic (horizontal -net, braking, and propulsive- and vertical impulses; peak vertical and horizontal forces). Flying time (FT) and SBRT were the dependent variables of stepwise multiple linear regression models. Stride length and horizontal hip displacement were the strongest determinants of SBRT (adjusted R2: 0.350, p < 0.05) while stride length of the FT (adjusted R2: 0.293, p < 0.05). Support angle solely contributed to SBRT (adjusted R2: 0.303, p < 0.05), whereas braking impulse and peak vertical force contributed as kinetic factors (adjusted R2: 0.609, p < 0.001). Only braking impulse was associated with FT (adjusted R2: 0.228, p < 0.05). Contact time and support angle correlated with peak vertical force (p < 0.05). Overall, kinetic variables outweigh kinematic and spatiotemporal parameters in explaining flying performance. When force platforms are unavailable, coaches may rely on stride length, contact time, and support angle.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149030904","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":"Physical Performance and Head Impact Exposure in Boys' Youth Ice Hockey.","authors":"Abigail G Swenson, Cole D Smith, Nicholas J Cavallero, Giovanny A Romero, Nicholas Stewart Pritchard, Garrett S Bullock, Christopher M Miles, Jason P Mihalik, Jillian E Urban, Joel D Stitzel","doi":"10.1519/JSC.0000000000005663","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005663","url":null,"abstract":"<p><strong>Abstract: </strong>Swenson, AG, Smith, CD, Cavallero, NJ, Romero, GA, Pritchard, N, Bullock, GS, Miles, CM, Mihalik, JP, Urban, JE, and Stitzel, JD. Physical performance and head impact exposure in boys' youth ice hockey. J Strength Cond Res XX(X): 000-000, 2026-Evidence suggests that physical performance influences head acceleration event (HAE) exposure in collision sports, especially in youth populations undergoing physical and neuromuscular development. Concern surrounding negative effects of HAE exposure highlights a need to better understand individual-level factors that may increase propensity for HAEs. Therefore, this study evaluated relationships between physical performance and HAE exposure in youth ice hockey. Athletes from one 14U (n = 10) and one 16U (n = 7) ice hockey teams completed on-ice and off-ice assessments at a preseason hockey performance combine event and wore custom instrumented mouthpieces measuring HAE frequency and magnitude across their respective seasons. Outcomes were per-player cumulative HAE magnitudes, HAE rates, and percentage of HAEs with direct head contact. Linear regressions adjusted for age division, body mass index (BMI), and position evaluated relationships between physical performance and HAE exposure. Athletes experienced 1,027 total HAEs. Multiple physical performance measures for both on- and off-ice tasks were significantly associated with HAE exposure metrics, though the strength and direction of these relationships varied by task. Relationships were additionally modified by age division, BMI, and position. Skating speed tasks yielded the strongest associations for on-ice tasks, with faster Reed skate times associated with reductions in cumulative game HAE magnitudes. For off-ice tasks, vertical jump height was associated with lower cumulative game HAE magnitudes and reduced rates of direct head contact across all sessions. Findings may be of interest to coaches and athletic trainers for injury risk management and ultimately present early opportunities for the development of physical performance-based strategies to reduce HAE exposure.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149030943","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":"Assisted Sprint Training: Individual Adaptations Linked to Force-Velocity Profiles and Spatiotemporal Variables.","authors":"Austra Skujytė, Viktoras Šilinskas, Eugenijus Trinkūnas, Inga Lukonaitienė, Pierre Samozino, Sigitas Kamandulis","doi":"10.1519/JSC.0000000000005525","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005525","url":null,"abstract":"<p><strong>Abstract: </strong>Skujytė, A, Šilinskas, V, Trinkūnas, E, Lukonaitienė, I, Samozino, P, and Kamandulis, S. Assisted sprint training: individual adaptations linked to force-velocity profiles and spatiotemporal variables. J Strength Cond Res XX(X): 000-000, 2026-This study investigated the effects of a 6-week assisted sprint training (AST) program on sprint performance, spatiotemporal variables, and force-velocity profiles in youth soccer players and explored whether baseline regular sprint characteristics were associated with individual adaptations. Twenty-four players aged 16.5 ± 2.1 years were allocated to a fully AST, partially AST, or control group. Both assisted groups completed 12 sessions of 30-m towed sprints using a motorized device. Sprint performance was assessed under regular and assisted conditions before and after training, while the F-V profile was derived from regular conditions before training. Assisted sprint times improved significantly in the intervention groups (4.24 seconds [95% confidence interval: 4.16-4.33] to 4.10 seconds [95% confidence interval: 4.01-4.20]; ηp2 = 0.26), but regular 30-m sprint times and spatiotemporal variables did not change significantly. High responders displayed greater initial force and power capacities (theoretical maximal horizontal force, maximal propulsive power, maximal ratio of force) than nonresponders. Regression analysis indicated that maximal propulsive power and maximal ratio of force were the strongest predictors of improvement (adjusted R2 > 0.53 for both), whereas a theoretical maximal velocity showed a weak association (adjusted R2 = 0.13). Overall, AST improved performance only under assisted conditions, with the observed adaptations likely driven in part by sensorimotor adjustments. However, there was great interindividual variability. These findings highlight the relevance of force-velocity profiling for identifying potential responders and suggest that AST provides limited short-term transfer to regular sprint performance.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149017208","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":"Assessing Inter-rater Reliability and Intra-rater Reliability During the 2-Minute Hand-Release Push-Up Event in the Army Fitness Test.","authors":"Drew Van Dam, Rachel Gidaro, Sarah Ferreira, Jenna Morogiello-Shaw, Dan Jaffe, Austin Semmel","doi":"10.1519/JSC.0000000000005673","DOIUrl":"10.1519/JSC.0000000000005673","url":null,"abstract":"<p><strong>Abstract: </strong>Van Dam, D, Gidaro, R, Ferreira, S, Morogiello, J, Jaffe, D, and Semmel, A. Assessing inter-rater reliability and intra-rater reliability during the 2-minute hand-release push-up event in the army fitness test. J Strength Cond Res XX(X): 000-000, 2026-The Army Fitness Test, implemented in 2025, assesses soldier readiness via 5 physically challenging events (3 repetition maximum deadlift, hand-release push-up, sprint-drag-carry, plank, and 2-mile run). Each event is graded by individuals with varying levels of experience, thus posing a threat to the reliability of the physical performance scores. The purpose of this study was to examine the inter-rater and intra-rater reliability of the two-minute hand-release push-up test to facilitate learning and improvement of assessing physical performance. Seventeen raters (5 female, 12 male) graded 10 hand-release push-up (HRPU) videos over 3 separate weeks (30 total videos, 60 total minutes). Each video contained a recording of a Cadet performing the two-minute HRPU test. Raters were required to provide a response after each repetition by stating \"yes\" for a proper repetition and \"no\" for an improper repetition. Researchers recorded all responses from raters in each of the 3 settings. Videos were randomized for each week of viewing with no rater viewing the videos in the same order. Using a logistic model, we were able to measure inter-rater and intra-rater reliability. Researchers calculated the intraclass correlation coefficient to evaluate overall reliability and agreement and Prevalence-Adjusted, Bias-Adjusted Kappa to further understand inter-rater and intra-rater reliability. Ultimately, we found that raters were not consistent as a group, with some showing significant fluctuations in their responses between tests. This finding is crucial because even small differences in scoring can negatively impact assessment on the HRPU event influencing a subjects's total score.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148990561","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":"A Practical Approach to Assess the Load-Velocity Profile in Sprint Swimming: Reliability of a Portable Resistance Device.","authors":"Pasquale Salerno, Marco Fassone, Marco Bove, Ambra Bisio","doi":"10.1519/JSC.0000000000005678","DOIUrl":"10.1519/JSC.0000000000005678","url":null,"abstract":"<p><strong>Abstract: </strong>Salerno, P, Fassone, M, Bove, M, and Bisio, A. A practical approach to assess the load-velocity profile in sprint swimming: Reliability of a portable resistance device. J Strength Cond Res XX(X): 000-000, 2026-The load-velocity (L-V) profile has recently been proposed as a practical model for describing sprint swimming performance. However, its application is often limited by the need for expensive, complex equipment, and by the lack of data on nonelite swimmers. This study examined the test-retest reliability of the L-V profile in front crawl swimming using an economical, portable isotonic resistance device. Twenty-six trained/developmental swimmers (11 females and 15 males) performed 2 identical testing sessions, with a 3-5 days interval between them. Each session consisted of 5 maximal 25-m semi-tethered front crawl sprints performed with different external loads. Swimming velocity was measured over a 5-m mid-pool section using video analysis. Individual L-V relationships were established through linear regression to estimate the following: theoretical maximal velocity (V 0 ); theoretical maximal load (L 0 ); relative load (rL 0 ); and slope of the L-V relationship (Slv). Test-retest reliability ranged from good to excellent in men (ICC = 0.86-0.95) and women (ICC = 0.86-0.94). Inter-rater reliability also showed good-to-excellent agreement across all variables (ICC = 0.86-0.98). Absolute reliability was acceptable, with coefficients of variation ≤8.8% and minimal systematic bias in Bland-Altman analyses. The L-V profile obtained using a portable isotonic resistance device demonstrates good-to-excellent reliability in front crawl swimming. This approach provides a practical and accessible method for estimating sprint swimming performance that can be used in daily training settings.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148982996","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":"Identification of Key Power Predictors of Bat Swing Speed in Youth Baseball Hitters Using PLS-SEM: Implications for Training Design.","authors":"Han-Soo Park, Ki-Jae Song, Yu-Eun Lim, Jun-Young Kim, Jin-Ho Yoon","doi":"10.1519/JSC.0000000000005599","DOIUrl":"https://doi.org/10.1519/JSC.0000000000005599","url":null,"abstract":"<p><strong>Abstract: </strong>Park, H-S, Song, K-J, Lim, Y-E, Kim, J-Y, and Yoon, J-H. Identification of key power predictors of bat swing speed in youth baseball hitters using PLS-SEM: Implications for training design. J Strength Cond Res XX(X): 000-000, 2026-Bat swing speed (BSS) is a critical performance metric in baseball, reflecting efficient energy transfer through the kinetic chain. This study aimed to identify key predictors of BSS in youth baseball hitters using partial least squares structural equation modeling. Ninety-six male players (age: 13.9 ± 1.1 years) participated. Bat swing speed was measured using an inertial measurement unit during standardized tee-ball swings. Players then completed 3 medicine ball throw (MBT) tests-rotational medicine ball throw (RMBT), backward overhead medicine ball throw (BOMBT), and seated medicine ball throw-to assess explosive upper- and whole-body power. Lower-body power was evaluated through countermovement jump (CMJ) testing on a force platform, from which propulsive peak force, propulsive peak power, total impulse, rate of force development, and jump height were derived. Partial least squares structural equation modeling results showed that MBT significantly predicted BSS (R2 = 0.654, f2 = 0.685, p < 0.001), with BOMBT and RMBT exhibiting the strongest factor loadings. Countermovement jump did not directly predict BSS but showed a significant indirect effect through MBT (β = 0.284, p < 0.001), indicating a foundational contribution of lower-body power to swing-specific performance. These findings suggest that MBT, particularly BOMBT and RMBT, serves as a practical, sport-specific tool for assessing BSS in youth baseball players. Although CMJ is not a direct predictor of swing velocity, it may reflect underlying neuromuscular readiness. Integrated upper- and lower-body power profiling may enhance training strategies for youth athletes.</p>","PeriodicalId":17129,"journal":{"name":"Journal of Strength and Conditioning Research","volume":" ","pages":""},"PeriodicalIF":3.0,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148990516","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}