Journal of Strength and Conditioning Research最新文献

Abstract: Lahti, A, Grundberg, A, Stenman, E, and Sundquist, K. Physical characteristics of Swedish female professional ice hockey players allowed body checking. J Strength Cond Res 39(3): e463-e468, 2025-In ice hockey, physical characteristics impact sporting performance. This study aims to describe body height, body mass, and body mass index (BMI) in professional female ice hockey players in the Swedish Women's Hockey League (SDHL), which is unique as it is (so far) the only women's league in the world that allows body checking. This study also compares physical characteristics by players' position and the players in SDHL with the nonchecking female North American Elite League (PWHL). In addition, attitudes toward body checking are examined. All 225 players registered in SDHL 2023/2024 were invited to participate. Data from 159 included players (71%) aged (mean ± SD ) 23.6 ± 4.5 years were analyzed. Body height, body mass, BMI, and attitudes toward body checking were assessed through a self-reported questionnaire. The mean body height was 169.1 ± 5.5 cm, body mass 68.4 ± 6.7 kg, and BMI 23.9 ± 1.9 kg·m -2 . No significant differences were found by player position or between the players in SDHL and PWHL. In total, 88% believed that it was good to introduce body checking in women's ice hockey and 64% did not believe that introducing body checking would increase the number of injuries. The observed characteristics may represent baseline reference values of physical characteristics in female ice hockey players allowed body checking. There is currently no difference in physical characteristics by players' positions or between checking and nonchecking leagues although such differences may occur in the future. Most players were positive toward body checking in women's ice hockey and did not believe that the number of injuries would increase by introducing it.

Abstract: Hardy, SGJ, Stelzer-Hiller, OW, Edwards, KM, and Freeston, J. Criterion validity and reliability of a new medicine ball rotational power test. J Strength Cond Res 39(3): e429-e435, 2025-This study assessed the validity and reliability of 2 medicine ball rotational power assessments, the novel push for maximum velocity by radar (MB vel ), and the commonly used push for maximum distance by tape measure (MB dis ), against the criterion reference 3-dimensional motion capture (MoCap) to identify the best-practice field-based assessment. Fifteen professional female cricketers volunteered for 2 testing sessions each comprising of a specific warm-up and 24 (12 MB vel , 12 MB dis ) maximal throws of a 2-kilogram medicine ball. Radar velocity and tape measure distance were compared with MoCap velocity and projectile motion calculated distance overall, and by dominant and nondominant sides. Statistical analysis included intraclass correlations (ICCs) for accuracy (1, 1) and reliability (3,1), Bland-Altman plots for bias precision and limits of agreement, linear regression ( R2 ) for variance, and Pearson's ( r ) for correlation. Significance was set α = 0.05. MB vel demonstrated excellent accuracy (ICC = 0.97 [0.97-0.98]), and nearly perfect agreement for bias (-0.09%) and precision (1.49%). Side-to-side analysis showed the same profile for MB vel dominant (ICC = 0.96 [0.95-0.97], bias -0.15%, precision = 1.55%) and nondominant sides (ICC = 0.97 [0.96-0.98], bias -0.05%, precision = 1.53%). MB vel demonstrated excellent reliability overall (ICC = 0.94 [0.82-0.98]) for dominant (ICC = 0.88 [0.69-0.97]) and nondominant sides (ICC = 0.93 [0.80-0.98]). MB dis showed poor accuracy (ICC = 0.38 [0.28-0.47]), large bias (12.43%), lower precision (4.55%), and moderate reliability (ICC = 0.72 [0.32-0.90]). The MB vel assessment validly and reliably measures rotational power performance, enabling practitioners to profile, benchmark, and assess the quality in the field.

Abstract: Kubiak, SM, Starns, EA, Wehler, RJ, Church, LA, and Roberts, JC. Evaluating disability inclusivity in accreditation standards for exercise science-related programs: a scoping review. J Strength Cond Res 39(3): e506-e515, 2025-The purpose of this scoping review was to determine the level of inclusivity for disability-related language within accreditation standards for exercise science-related bachelor and graduate education programs. Standards from 4 U.S. exercise science-related programmatic accrediting organizations were included in this study. Using the World Health Organization's International Classification of Functioning, Disability, and Health (ICF) framework, each standard ( N = 1,043) was classified as either containing disability-related language or not based on the 8 ICF function and structure categories. Owing to the broad ICF disability framework, standards were further analyzed using open coding. Frequencies and percentages of exercise science-related accreditation standards that included or lacked disability language and to what extent were reported. Of the 1,043 standards, 417 were classified as including language related to at least 1 of the 8 ICF categories. Using a more specific disability definition from the Centers for Disease Control and Prevention, standards were further analyzed and coded as "knowledge of" disability ( n = 281; 27%), "application of" knowledge ( n = 64; 6%), 21 standards were classified as both (2%), and 677 (65%) were classified as having no disability language. "Knowledge of" and "application of" coded standards were further organized according to subcodes (disability, risk factors, both disability and risk factors, and basic life support or emergency care). The lack of inclusive language identified revealed a critical need to reexamine the inclusivity of disability in accreditation standards to ensure educational curricula equip future fitness professionals with the education and experience needed to confidently and effectively serve persons with disabilities.

Abstract: Agar-Newman, DJ, Funk, S, Cavin, E, Geneau, MC, Tsai, MC, and Klimstra, M. Determining the threshold of unweighting in squat jumps: a study on jump height and unweighting amplitude. J Strength Cond Res 39(3): 295-299, 2025-Squat jumps (SJs), involving only an upward propulsive phase, are commonly used in athletic assessment and research. Unfortunately detecting an unweighting phase before the upward propulsive phase is typically done subjectively by observing the athlete or inspecting the force-time trace, and there is no clearly established threshold of unweighting for a valid SJ. This reliance on subjectivity to determine a valid SJ has the potential to result in misleading findings or incorrect training interventions. Therefore, the aim of this study was to determine at what threshold of unweighting does SJ height increase. To answer this question, 56 female athletes, mean (±SD) body mass (BM) 76.26 ± 12.40 kg, height 1.68 ± 0.06 m, age 22.23 ± 1.47 years performed 936 SJs, under 4 different external loads. Squat jumps were divided into 6 separate groups based on the amplitude of unweighting relative to BM and an analysis of covariance was run with jump height as the dependent variable, unweighting group as the fixed factor, and external load as a covariate. There was a significant difference in jump height (F (5,930) = 13.65, p < 0.01) between unweighting groups while controlling for external load. Post hoc testing using Dunnett test showed that all SJ unweighting thresholds >2% BM (p < 0.01) resulted in an increased jump height from the threshold of ≤1% BM. Therefore, to maintain the validity of SJs as a measure, a threshold of 2% BM for unweighting amplitude is recommended. Adhering to this threshold will eliminate subjectivity in identifying valid SJs and potentially enable practitioners to automate the process using algorithms.

Abstract: Gdovin, JR, Hogan, B, and Williams, CC. Limiting access to resistance training equipment during the off-season: the impact on collegiate pitching metrics. J Strength Cond Res 39(3): 347-351, 2025-Resistance training has been shown to improve overhead throwing velocity, but it is unknown as to how limiting access to a strength and conditioning facility affects a baseball pitcher's readiness for the spring season. Therefore, the purpose of this study was to examine the influence of an individualized pitching program on pitching metrics during an 8-week fall season in collegiate baseball pitchers without a simultaneous structured strength training program. Twelve National Collegiate Athletic Association Division-I baseball pitchers completed the study and wore a PULSE Throw Workload Monitor to track peak arm slot angle, peak arm velocity, and peak elbow varus torque, while a radar gun measured ball velocity. An 8-week pitching program had subjects throw 30 and 50 maximum effort pitches in the first and eighth week, respectively, while workload increased by 5 maximum effort pitches every 2 weeks. Paired samples t -tests were conducted to compare variables of interest before and after an 8-week fall season with an alpha level set at 0.05. There was no significant difference in peak arm slot angle, peak arm velocity, and peak elbow varus torque ( p > 0.05); however, there was a significant decrease in ball velocity ( p < 0.001). These data indicate that 8-week pitching programs, not coupled with a resistance training regimen, negatively affect a pitcher's ball velocity. Sport coaches and practitioners should thus make accommodations to access the necessary equipment for a pitching and strength training program to be implemented simultaneously to ensure that pitchers are prepared to perform at an optimal level during the spring season.

Abstract: Brooks, SG, Peach, HD, Howden, R, Lowrie, J, and Marino, JS. Impact of perfectionism on the risk of the female athlete triad in collegiate athletes. J Strength Cond Res 39(3): e444-e450, 2025-The female athlete triad is a metabolic syndrome affecting physically active female athletes, especially in high-level athletics. Little is known about the relationship between psychological factors and triad risk. This study aimed to investigate the risk of triad development and the relationship with perfectionistic tendencies in female collegiate athletes. Division I female college athletes ( N = 25) (mean age 20.2 ± 1.2) completed the Sport Multidimensional Perfectionism Scale 2, Low Energy Availability in Females Questionnaire, Female Athlete Screening Tool, and medical history surveys. Subjects then received a whole-body dual-energy x-ray absorptiometry scan for body composition and bone density measurements; 60% of subjects were at a moderate risk of developing the triad and 8% were at a high risk. This indicates that there is a high prevalence of triad risk in this population, pointing to the need for better screenings. Subjects with greater perfectionistic tendencies had a greater risk for triad development ( r = 0.58), especially when those tendencies manifest in maladaptive dimensions (concerns over mistakes r = 0.75, doubts about actions r = 0.64) ( p ≤ 0.05). No significant correlations were established between adaptive dimensions and triad risk, suggesting that athletes with high perfectionistic tendencies that manifest in positive ways may not experience increased risk of the triad or disordered eating. The findings provide a greater understanding of the psychological role perfectionism plays in the development of the triad and help identify behaviors that place athletes at a higher risk.

Abstract: Horníková, H, Hadža, R, and Zemková, E. The contribution of perceptual-cognitive skills to reactive agility in early and middle adolescent soccer players. J Strength Cond Res 39(3): e478-e484, 2025-Agility performance increased from childhood to mid-adolescence, followed by a plateau until early adulthood. Because adolescence is crucial for the development of perceptual-cognitive skills, the question is whether and to what extent its contribution to reactive agility increases during developmental periods of adolescence in invasive sports athletes. This study investigated the association of reactive agility with the speed of decision making, sprint speed, and explosive strength in early and middle adolescent soccer players. They performed reactive and preplanned Y-shaped agility tests, choice reaction time test, modified half T-test, 30-m sprint (10 m split), and countermovement jump (CMJ). The reactive agility time in both age groups significantly correlated with 30-m sprint time ( r = 0.839, p < 0.001, and r = 0.745, p = 0.001, respectively), pre-planned Y-shaped agility time ( r = 0.828, p < 0.001, and r = 0.644, p = 0.007, respectively), 10-m sprint time ( r = 0.823, p < 0.001, and r = 0.775, p < 0.001, respectively), time in modified half T-test ( r = 0.723, p < 0.001, and r = 0.630, p = 0.009, respectively), and CMJ height ( r = -0.744, p < 0.001, and r = -0.615, p = 0.013, respectively), although with the index of reactivity in middle adolescent soccer players only ( r = 0.615, p = 0.011). Based on R2 , the explained proportion of variance was 53.6% for linear sprint speed and 30.1% for a change of direction speed in early adolescence, whereas it was 54.6% for acceleration speed and 31.8% for decision-making in middle adolescence. This indicates the significant contribution of speed factors to reactive agility in both adolescent groups, whereas perceptual-cognitive factors in middle adolescent soccer players only. It seems that even during the relatively short period of adolescence, the changes occur in the contribution of perceptual-cognitive skills to reactive agility in athletes practicing invasive sports.

Abstract: Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Páez-Maldonado, J, Rodiles-Guerrero, L, Sánchez-Moreno, M, Gómez-Guerrero, G, León-Prados, JA, and Pareja-Blanco, F. Acute responses to different lifting velocities during squat training with and without blood flow restriction. J Strength Cond Res 39(3): 307-317, 2025-The aims of the research were to compare the acute mechanical, metabolic, neuromuscular, and muscle mechanical responses to different lifting velocities (maximal vs. half-maximal) under distinct blood flow conditions (free [FF] vs. restricted [BFR]) in full-squat (SQ). Twenty resistance-trained males performed 4 protocols that differed in the velocity at which loads were lifted (MaxV: maximal velocity vs. HalfV: half-maximal velocity) and in the blood flow condition (FF: free-flow vs. BFR: 50% of arterial occlusion pressure). The relative intensity (60% 1 repetition maximum), volume (3 sets of 8 repetitions), and resting time (2 minutes) were matched between protocols. Mean propulsive force (MPF), mean propulsive velocity (MPV), mean propulsive power (MPP), and electromyography (EMG) values were recorded for each repetition. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ), maximal voluntary isometric contraction in 90° SQ, and performance with the load that elicited a 1-m·s -1 velocity at baseline measurements (V1-load) in SQ were assessed at pre-exercise and postexercise. The MaxV protocols showed significantly greater MPF, MPV, MPP, and EMG amplitude during the exercise than the HalfV protocols (velocity effect, p < 0.05). The FF protocols achieved higher MPF and MPP during exercise than BFR (BFR effect, p < 0.05). The BFR protocols induced greater blood lactate after exercise (BFR × time interaction, p = 0.02), along with higher postexercise impairments in mechanical performance (BFR × time interaction, p < 0.05). The MaxV protocols elicited superior performance and greater muscle activation during exercise. The BFR protocols resulted in lower force and power production during exercise and exhibited higher performance impairments and increased metabolic stress postexercise.

Abstract: Jagim, AR, Horswill, CA, Dobbs, WC, Twohey, EE, Tinsley, GM, Fields, JB, and Jones, MT. Minimum wrestling weight for high school girls wrestling: Time to revisit minimal body fat percent. J Strength Cond Res 39(3): 332-339, 2025-The purpose of this study was to determine whether an alternative body fat percentage (BF%) could be established as a safer margin for minimal wrestling weight (MWW) determination by evaluating the distribution of BF% and MWW values naturally occurring for high school girls wrestling. Data from the 2022-2023 high school season were retrospectively analyzed. In total, 33,321 female wrestlers completed skinfold (SKF) assessments or bioelectrical impedance analysis (BIA) in accordance with sport governing body mandates for weight certification. Frequency statistics and descriptive analysis were performed to compute normative MWW and BF% profiles. Body fat percentage thresholds of 12% (12MWW) and the BF% value defining the lowest fifth percentile were used to determine the resulting MWW and minimum weight class for each method. The median ± interquartile range for BF% was 28.3 ± 9.2%. There was a difference ( p < 0.001) in BF% values between BIA (28.4 ± 6.8%) and SKF (29.4 ± 7.6%), but a trivial effect size (ES = 0.14). The fifth percentile for BF% was 19%, which was used for alternative MWW determination (19MWW). 12MWW and 19MWW were 11.2 ± 6.4 kg ( p < 0.001; ES = 1.8) and 8.6 ± 7.7 kg ( p < 0.001; ES = 1.1) lower than the body mass of the wrestlers at the time of weight certification. Nearly all BF% values were above the 12% threshold currently used to determine MWW. Current body weights were more than 9.1 kg above MWW values for both 12MWW and 19MWW. Increasing the minimum BF% threshold from 12 to 19% would affect a small percentage of wrestlers and improve the margin of safety for those intent on achieving a lower weight class.

Abstract: Favro, F, Roma, E, Gobbo, S, Bullo, V, Di Blasio, A, Cugusi, L, and Bergamin, M. The influence of resistance training on joint flexibility in healthy adults: A systematic review, meta-analysis, and meta-regression. J Strength Cond Res 39(3): 386-397, 2025-Joint flexibility is a key component of physical fitness. Despite the large body of evidence regarding the effectiveness of muscle stretching exercises, little is known about the effect of resistance training on flexibility. A systematic search was conducted on 9 academic search instruments; inclusion criteria were as follows: healthy adult participants (age ≥18 years); resistance training intervention (duration ≥4 weeks); at least one flexibility outcome. Risk of bias was assessed using the RoB-2 and ROBINS-I tools. A 3-level meta-analysis was conducted, with multiple outcomes nested within each study. A moderator analysis was conducted by fitting a meta-regression model. Significance level was set at p < 0.05. We included 36 studies (1,469 participants). None of the included papers resulted at a low risk of bias. The pooled effect size for resistance training on flexibility was g = 0.6325, with 95% CI: 0.4762 to 0.7888 ( p < 0.0001). There was a substantial amount of heterogeneity between studies. Exercise intensity was a significant moderator ( p < 0.0225, high vs low), based on 129 and unique effect sizes, and sex ( p = 0.0429). Activity level and age were nonsignificant moderators. Resistance training could be implemented as a strategy to improve joint flexibility, with high-intensity protocols resulting in a magnified effect. However, the high overall risk of bias and substantial heterogeneity limit our ability to draw definitive conclusions.