Journal of Strength and Conditioning Research最新文献

Abstract: Feeney, KA, Melton, BF, Ryan, GA, Bland, HW, and Butler, CR. The association between body composition and performance on military fitness tests. J Strength Cond Res 39(1): 94-98, 2025-Body composition and physical testing are important considerations for military personnel. However, limited research exists on the potential relationship between these 2 factors. The purpose of this retrospective cohort study was to examine the correlations between several body composition measures and performance on the components of 2 separate fitness tests in Air Force special warfare candidates. Within the cohort of candidates, 1,036 completed body composition testing, 1,002 completed a calisthenic-based fitness test, and 562 completed a fitness test designed to mimic occupational tasks. Analysis of Pearson correlations indicated that the calisthenic-based test weakly favored candidates with lower body mass and body fat levels on the lower end of that found within the cohort studied, while a higher score on the occupational-based test was linked to higher body mass index (BMI) and skeletal muscle mass (SMM) and lower absolute and relative body fat levels. Individual components of the occupational-based test favored different body composition relationships. A large negative association was seen between the farmer's carry time and SMM (r = -0.53) and a moderate negative association between farmer's carry time and body mass (r = -0.46), p < 0.01. The weight lifted during 3-RM deadlift demonstrated moderate positive associations with body mass (r = 0.49), BMI (r = 0.50), and SMM (r = 0.49), p < 0.01. These results suggest that individuals in physically active military roles should maximize SMM while managing body fat levels.

Abstract: Watson, A, Murray, A, Coughlan, D, Wells, J, Ehlert, A, Xu, J, Turner, A, and Bishop, C. Understanding training load in golf: A survey of swing coaches, performance practitioners, and medical staff. J Strength Cond Res 39(1): e20-e29, 2025-The present study aimed to investigate the current opinions and practices of golf coaches, performance practitioners, and medical staff working in golf, on the topic of monitoring training load in the sport. A cross-sectional, explorative survey was undertaken, which included specific questions for each subgroup using a combination of Likert scale and "Yes" or "No" questions. A total of 89 practitioners completed the survey with 23 being golf coaches, 35 being performance practitioners, and 31 being medical practitioners. Results showed that virtually all technical coaches and support staff practitioners agreed on the importance of monitoring training load in golf. However, our findings identified a noticeable gap between what is current opinion and what is actually done in day-to-day practice, relating to training load monitoring in the sport. Although the majority of coaches and practitioners are in agreement with the value of assessing load in golf, the number that actually monitor and collect data relating to this is substantially lower. Therefore, further consideration and research is undoubtedly required on this topic to help inform and change current practice in golf.

Abstract: Cardoso, F, Costa, MJ, Colaço, P, Vilas-Boas, JP, Pinho, JC, Pyne, DB, and Fernandes, RJ. Ventilatory and perceived ergogenic effects of mandibular forward repositioning during running at maximal oxygen uptake intensity. J Strength Cond Res 39(1): e13-e19, 2025-Wearing an intraoral dental splint may enhance ventilatory function and exercise performance. Nineteen runners performed on a 400-m outdoor track: (a) an incremental protocol to assess the velocity at maximal oxygen uptake (vV̇ o2 max) and (b) 2 square wave bouts wearing 2 intraoral splints (with and without mandibular forward repositioning). The time until exhaustion at vV̇ o2 max (TLimv V̇ o2 max), ventilatory variables, oxygen uptake (V̇ o2 ) kinetics, energetic profiling, perceived exertion and kinematics, were all measured. Ventilatory data were assessed breath-by-breath and perceived exertion evaluated using the Borg 6-20-point scale at the end of TLimv V̇ o2 max bouts. Images were recorded by video cameras (120 Hz) and kinematic measures retrieved using Kinovea. A paired t test was computed for comparison of splints ( p ≤ 0.05). With (vs. without) mandibular forward repositioning, runners increased their TLimv V̇ o2 max by ∼6% ( p = 0.03), coupled with higher ventilation (151 ± 22 vs. 147 ± 23 L·min -1 , p = 0.04), end-tidal oxygen tension (114.3 ± 3.7 vs. 112.9 ± 3.9 mm Hg, p = 0.003), and lower inspiratory time (0.526 ± 0.083 vs. 0.540 ± 0.090 seconds, p = 0.02), despite similar V̇ o2 kinetics (e.g., 49.0 ± 8.7 vs. 47.7 ± 8.6 ml∙kg∙min -1 of fast component amplitude) being observed. The energy expenditure was ∼8% higher ( p = 0.03) with the mandible forward, coupled with lower perceived exertion scores ( p = 0.04). Mandibular forward repositioning was effective in acutely improving running performance at vV̇ o2 max with ergogenic effects on ventilatory and perceived variables.

Abstract: Gereduz Agapito, L, Brownstein, CG, and Maffiuletti, NA. Effects of soccer match-play on muscle strength, physical performance, and perceptual responses in elite female players. J Strength Cond Res 39(1): 79-85, 2025-The purpose of this study was to investigate the impact of actual soccer match-play on muscle strength, physical performance, and perceptual responses in elite female players. Twelve Swiss elite players were tested before (pre), after (post) and 48 hours after a 90-minute soccer match for knee and hip muscle strength, vertical jump height, and sprint time. Perceptual responses were also evaluated up to 72 hours postmatch with a self-reported questionnaire. Muscle strength, jump, and sprint performance were impaired at post compared with pre (p < 0.001), but fully recovered at 48 hours. Percent strength losses were higher for knee flexors (∼20%) compared with both hip adductors (∼12%; p = 0.005) and abductors (8-12%; p < 0.001), and for knee extensors compared with hip abductors (p = 0.013). Regardless of muscle group, strength losses were higher on the dominant than on the nondominant side (p = 0.010). Most perceptual responses were altered after the match (p < 0.001) and some items such as motivation to train and readiness to play remained unrecovered at 72 hours (p < 0.01). Soccer match-play induced a significant decline of knee and hip muscle strength in elite female players that was more marked for knee flexors than for hip muscles. This was accompanied by performance impairments and by altered perceptual responses that still persisted 72 hours after the match. These findings offer implications for the optimization of postmatch recovery strategies in elite female soccer players.

Abstract: Sandau, I and Kipp, K. Prediction of snatch and clean and jerk performance from physical performance measures in elite male weightlifters. J Strength Cond Res 39(1): 33-40, 2025-This study aimed to build a valid model to predict maximal weightlifting competition performance using ordinary least squares linear regression (OLR) and penalized (Ridge) linear regression (penLR) in 29 elite male weightlifters. One repetition maximum (1RM) or 3RM test results of assistant exercises were used as predictors. Maximal performance data of competition and assistant exercises were collected during a macrocycle in preparation for a competition. One repetition maximum snatch pull, 3RM back squat, 1RM overhead press, and body mass were used to predict the 1RM snatch; and 1RM clean pull, 3RM front squat, 1RM overhead press, and body mass were used to predict the 1RM clean and jerk. Model validation was performed using cross-validation (CV) and external validation (EV; random unknown dataset) for the coefficient of determination and root mean square error (RMSE). Results revealed that penLR models present more plausible output in the relative importance of highly correlated predictors. Of note, the 1RM snatch pull is the most relevant predictor for the 1RM snatch, whereas the 1RM clean pull and 3RM front squat are the most relevant predictors for the 1RM clean and jerk. Validation-based absolute predictive error (RMSE) ranged between ≈ 3-9 kg for the 1RM snatch and ≈ 3-7 kg for the 1RM clean and jerk, depending on the model (OLR vs. penLR) and validation procedure (CV vs. EV). In conclusion, penLR models should be used over OLR models to analyze highly correlated predictors because of more plausible model coefficients and smaller predictive errors.

Abstract: Curtis, M, Kupperman, N, Westbrook, J, Weltman, AL, Hart, J, and Hertel, J. Neuromuscular performance and the intensity of external training load during the preseason in National Collegiate Athletic Association Division I men's collegiate basketball players. J Strength Cond Res 39(1): 54-61, 2025-The aim of the study was to determine whether acute changes in neuromuscular performance can be detected through countermovement jumps (CMJs) conducted pre- and postpractice sessions in conditions of high or low intensity measured by microsensors technology. Using an observational repeated measures design, data were collected from 10 male collegiate basketball players. Countermovement jump data were collected before and after practice exposures over 4 weeks of preseason. Select CMJ kinetics were compared in conditions of high and low training load intensity to detect neuromuscular performance changes in displacement of the center of mass and kinetics. Kinetic measures were categorized as output, underpinning, and strategy-related variables. We investigated "output" defined as displacement (jump height [JH]), "underpinning" defined as force-related (mean eccentric force, mean concentric force, force at zero velocity), and "strategy" defined as time-related (countermovement depth [CMD], eccentric duration (EccDur), concentric duration [ConcDur]) variables. There were significant condition × time interactions in CMJ variables namely eccentric mean force (EccForce), force at zero velocity (Force@0), CMDepth, EccDur, and ConcDur. In conditions of high intensity, players had significant, but small decreases in EccForce and Force@0, with small increases in CMD, EccDur, and ConDur, respectively. However, there were no significant decreases in JH. High-intensity practice exposures did not impact neuromuscular performance specific to "output," suggesting that collegiate basketball athletes can maintain JH despite alterations in "underpinning" and "strategy-related" variables. This could have relevance in understanding how fatigue associated with higher-intensity training exposures may potentially alter jump strategy and force production capacities due to external load intensity in collegiate basketball athletes.

Abstract: Lewis, A, Rattray, B, and Flood, A. Does cathodal preconditioning enhance the effects of subsequent anodal transcranial direct current stimulation on corticospinal excitability and grip strength? J Strength Cond Res 39(1): e1-e12, 2025-Inconsistent effects of transcranial direct current stimulation (tDCS) on corticospinal excitability (CSE) and exercise performance are commonly reported. Cathodal preconditioning, involving cathodal tDCS delivered before anodal tDCS over the same region, may enhance changes in CSE and exercise beyond that resulting from anodal tDCS alone. This study aimed to investigate whether the effects of anodal tDCS on CSE and isometric grip strength can be enhanced by cathodal preconditioning. Thirty-five healthy subjects aged 19-37 years completed a familiarization session followed by 4 stimulation conditions presented in a randomized cross-over design across 4 separate sessions. tDCS doses were applied at 2 mA over the primary motor cortex for 10 minutes. Corticospinal excitability was assessed using 120% of resting motor threshold and an input/output curve of motor evoked potentials of the first dorsal interosseous. Grip strength was evaluated as time to exhaustion (TTE) in a sustained isometric contraction. Relative to conventional sham stimulation, TTE was significantly increased by 15% after conventional anodal tDCS. Corticospinal excitability increased in response to tDCS, but this effect did not differ across conditions. Cathodal preconditioning before anodal stimulation did not increase CSE or grip strength beyond that seen in the other stimulation conditions. Our findings did not reveal any significant impact of stimulation type on CSE. Notably, anodal tDCS led to a significant improvement in grip strength endurance. However, cathodal preconditioning did not seem to increase the effect of subsequent anodal stimulation on CSE nor grip strength.

Abstract: Tinsley, GM, Meyer, MK, Ptak, SM, Yu, D, Provost, JA, Hansen, NJ, and Carbuhn, AF. Body composition changes over a collegiate playing career in NCAA Division I women's soccer players. J Strength Cond Res 39(1): e40-e55, 2025-Although body composition is known to influence success in organized sport, the longitudinal body composition changes produced by sport specialization are not well characterized for women's soccer. To address this need, this study reports the body composition changes of NCAA Division I women's soccer players over their entire collegiate playing career. Serial dual-energy x-ray absorptiometry (DXA) scans were performed throughout players' involvement in collegiate women's soccer. Analyses of all players with multiple DXA scans (n = 80) and players with ≥3 years of DXA data (n = 17) were performed using linear mixed-effects models that included effects of time, playing position, game minutes, and interactions. In all athletes (n = 80; 2.1 ± 1.2 years of participation), significant increases in bone mass (1.4%), total lean mass (1.7%), and fat-free mass index (0.3 kg·m-2) occurred. These changes coincided with increased arm and leg bone mass, increased lean mass in all regions, and decreased body fat percentage and leg fat mass. In athletes with ≥3 years of collegiate data (n = 17; 3.5 ± 0.4 years of participation), larger increases in bone mass (3.0%), bone mineral density (2.2%), total lean mass (2.5%), fat-free mass index (0.4 kg·m-2), and segmental bone and lean mass were observed. Larger decreases in body fat percentage and leg fat mass were also noted. Although playing position was related to body composition characteristics, changes in outcomes were generally unrelated to position or game minutes. In summary, beneficial changes in multiple aspects of body composition were observed over years of participation in a collegiate women's soccer program.

Abstract: Barillas, SR, Lloyd, RS, Pedley, JS, and Oliver, JL. Different external cues elicit specific kinetic strategies during a drop jump in well-trained adolescent soccer players. J Strength Cond Res 39(1): e30-e39, 2025-The purpose of this study was to examine how different external cues that focus on jump height and ground contact time influence kinetic outcomes from a drop jump (DJ) in well-trained young soccer players. Following familiarization, 21 adolescent male soccer players performed 2 DJ trials under 4 different cue conditions: a height cue instructed subjects to jump to the ceiling, a ground contact cue instructed subjects to get off the ground as fast as possible, a combined condition joined both cues together, whereas a neutral cue with no external focus was used as a control condition. The height and contact time cues elicited specific kinetic responses that were significantly different to other conditions (p < 0.05); the height cue increasing impulses (d = 1.17-1.21) and jump height (d = 0.68), with the contact cue shortening ground contact time (GCT) (d = 1.27), increasing vertical stiffness (d = 1.48) and increasing force (d = 1.20-1.36). When combining the height and contact cue, a combination of significant (p < 0.05) kinetic responses were also observed, albeit to a lesser effect. Specifically, the combined cue increased impulse (d = 0.71-0.76) and jump height (d = 0.57) compared with a contact cue and a height cue, increased reactive strength index (d = 0.34), force (d = 0.69-0.83), and vertical stiffness (d = 0.75) while also reducing GCT (d = 0.69). Practitioners working with well-trained adolescent soccer players can use different external cues to effectively influence the kinetic strategies employed during a DJ.