Journal of Strength and Conditioning Research最新文献

Abstract: Chiron, F, Gulören, B, Erblang, M, Poirier, C, Elbaz, M, Servonnet, A, Gaudin, M, Le Coz, C, Lopes, P, Chennaoui, M, Hanon, C, Léger, D, and Thomas, C. Exploring the influence of coherent breathing on psychophysiological stress during a simulated 3-day 400-m race. J Strength Cond Res XX(X): 000-000, 2025-Managing psychophysiological stress is essential for elite athletes, especially during the high-intensity competitive period. Coherent breathing has been proposed as a noninvasive strategy to enhance recovery by modulating autonomic, neuroendocrine, and inflammatory responses. This study investigated the effects of coherent breathing on the autonomic nervous system (ANS), hypothalamic-pituitary-adrenal (HPA) axis regulation, inflammatory response, and sleep parameters in well-trained athletes undergoing repeated supramaximal efforts. Twenty-two athletes (N = 22) were randomly assigned to a control group (CONT, n = 11) or a coherent breathing group (RELAX, n = 11). Over an 8-day protocol simulating competition, athletes completed 3 400-m races. Heart rate variability, salivary biomarkers (alpha-amylase, cortisol, testosterone IL1-β), and sleep parameters were assessed throughout this study. Two-way repeated measure ANOVA revealed that the RELAX group showed significantly increased parasympathetic activity (root mean square of successive difference, p < 0.01) and a more stable cortisol response (p < 0.01) compared with the control group. The RELAX group also exhibited lower IL1-β levels (p < 0.05), longer total sleep duration (p < 0.05), and reduced sleep latency (p < 0.05). No significant differences in athletic performance were observed between groups. Coherent breathing effectively modulates psychophysiological stress by enhancing ANS balance, regulating HPA axis activity, reducing inflammatory responses, and improving sleep quality. This accessible and low-cost intervention may support recovery and resilience in athletes exposed to repeated high-intensity efforts.

Abstract: McClean, ZJ, da Silva Torres, R, Herzog, W, Pasanen, K, Lun, V, Nimphius, S, and Jordan, MJ. The influence of sport representation and attitudes toward strength training on neuromuscular performance profiles in university athletes: part I female athletes. J Strength Cond Res XX(X): 000-000, 2025-Neuromuscular performance is often assessed across strength, power, and plyometric tasks in athlete populations with an increasing emphasis on biomechanical testing that yields multifaceted data sets with several outcome measures per task. This leads to specific challenges in determining relevant neuromuscular performance benchmarks especially when considering contextual factors related to the sport environment. Thus, characterizing athlete neuromuscular performance subpopulations (or profiles) while accounting for the influence of contextual factors such as those related to the sport environment, and psychosocial factors such as the athlete's attitudes toward strength training could provide a framework for more specific neuromuscular benchmarks. Therefore, neuromuscular performance profiles were explored in female university athletes while accounting for sport influences and attitudes toward strength training. Female university athletes ( n = 192) from 5 sports completed a comprehensive lower body neuromuscular performance testing battery and surveys assessing attitudes toward strength training. Clustering was done to define neuromuscular performance profiles and Fisher's Exact Tests were used to examine differences in attitudes toward strength training across clusters. A high-strength/high-power/high-stiffness cluster, low-strength/low-power/low-stiffness cluster, and low-strength/low-power/high-stiffness cluster were identified with no difference in sport representation but differences in attitudes toward strength training ( p < 0.047; alpha = 0.05). These findings may help to quantify the characteristics of different female university athlete neuromuscular performance profiles while accounting for potential sport and psychosocial influences. One potential application of these results is to inform neuromuscular performance benchmarks that can be used in conjunction with preseason evaluations or in the context of restoring performance readiness after injury.

Abstract: Menek, B, Dansuk, E, and Arslan, T. The effects of soft tissue mobilization and vibration therapy on balance, explosive strength, and functional performance in elite rowers. J Strength Cond Res XX(X): 000-000, 2025-This study aimed to examine the acute effects of Instrument-Assisted Soft Tissue Mobilization (IASTM) and percussion massage therapy (PMT) on balance, explosive strength, and muscle performance in elite rowers. Forty-five elite-level rowers were randomly allocated to 3 groups: IASTM (n = 15), PMT (n = 15), and control (n = 15). All interventions were administered once under standardized conditions. Outcome measures included the Y Balance Test (YBT) for dynamic balance, the Triple Hop Test (THT) for explosive strength, and handheld dynamometry for quadriceps and gastrocnemius muscle strength. Significant improvements in YBT scores were observed in both IASTM and PMT groups compared with the control group (p < 0.05). Triple Hop Test results revealed a significant increase in nondominant limb jump distances in both intervention groups (p < 0.05), with no changes in the control group or in dominant limb performance (p > 0.05). In the PMT group, quadriceps and gastrocnemius strength significantly increased across all parameters (p < 0.05). In the control group, only nondominant quadriceps strength improved (p < 0.05). In contrast, the IASTM group showed significant reductions in both muscle groups (p < 0.05). Between-group comparisons showed no significant differences between IASTM and PMT groups for balance or explosive strength outcomes (p > 0.05); however, PMT outperformed IASTM in muscle strength measures (p < 0.05). In conclusion, a single session of PMT led to acute improvements in balance, nondominant limb explosive strength, and muscle strength in elite rowers. Although IASTM improved balance and explosive performance, it reduced muscle strength. PMT may be more suitable for use in preactivity warm-up routines to enhance neuromuscular readiness in elite athletes.

Abstract: Bell, SK and Spriet, LL. Rehydration following exercise-induced fluid losses: comparing flavored water, coconut water, and carbohydrate-electrolyte sports beverage. J Strength Cond Res XX(X): 000-000, 2025-Effective fluid volume and electrolyte replacement after exercise is essential to rehydration and optimal athletic performance. Despite coconut water's (CW) inherently high electrolyte content, there is still limited supporting evidence on its use and rehydration efficacy. The following study investigated the rehydration efficacy and palatability of natural CW compared with flavored water (FW) and carbohydrate-electrolyte sports (CES) beverage, after exercise-induced dehydration. During this randomized, single-blind, cross-over study, 8 recreational athletes (7 men, 1 woman; 22.3 ± 0.4 years and 48.2 ± 2.2 ml min kg-1 V̇o2max), cycled at 70% V̇o2max for 60 minutes until dehydrated by 1.36 ± 0.1% (1.07 ± 0.1 kg) of initial body mass (BM). During separate trials, subjects ingested 1 of 3 electrolyte beverages: FW, CW, or CES in volumes equivalent to 150% of BM lost. Hydration status was assessed with body mass measures and urine volume collections. Perceptual measures of beverage saltiness, thirst, and nausea were recorded using a 5-point Fluid Sensation Scale. After rehydration, FW produced statistically greater total urine output (530 ± 119.2 ml) compared with CW (170 ± 35.8 ml) and CES (170 ± 35.8 ml), p < 0.05. Subjects retained the greatest fluid volume with CW, but fluid status post rehydration was statistically insignificant between all beverages (p > 0.05). Perceived thirst was significantly greater for FW and CES at 0 minutes of rehydration (p < 0.05), while saltiness and nausea were insignificantly different between trials (p > 0.05). This study demonstrated that potassium-rich CW as a natural electrolyte rehydration alternative is equally effective in rehydration and palatability as the commercial CES drink, after moderate-to-high intensity exercise, despite having lower sodium concentrations.

Abstract: Everard, E, Carroll, P, Doherty, S, Harrison, M, and Krustrup, P. Normative data for physical activity and heart rate metrics of recreational football among the general male population-the Football Cooperative initiative. J Strength Cond Res XX(X): 000-000, 2025-Owing to established benefits associated with recreational football, there has been increased focus on developing the concept of Football is Medicine. This is leading to the development of more formalized and larger scale recreational football initiatives in general populations, such as the Football Cooperative (FC) in Ireland. The aim of this study was to determine the physical activity and heart rate (HR) metrics of FC games and to compare these metrics between the 2 FC game sites. One hundred two men (age: 37.4 ± 8.5 years, height: 176.2 ± 18.2 cm, body mass: 90.6 ± 21.5 kg) volunteered for this study. The games were 9 vs. 9 and 30 minutes per half on an astroturf pitch (36.5 × 27.5 m). Global Positioning Systems and chest-strap HR monitors were used to measure physical activity and HR metrics, respectively. Subjects ran an average of 6,632 m with 32 accelerations per session. Furthermore, subjects had a HRmean of 77% of their peak HR achieved during matches (Match-HRpeak) and played 81% of the time above 70% Match-HRpeak, 52% above 80% Match-HRpeak, and 23% above 90% Match-HRpeak. Despite a mean age difference of 10 years between the 2 sites, the only significant physical activity differences between sites were maximum speed and high-speed running. This was the first study to provide normative data for HR and physical activity metrics related to a 9 vs. 9 recreational football initiative. The results show recreational football provides a training stimulus in relation to HR metrics and distances covered that is to the upper ranges of recommended exercise guidelines.

Abstract: Hirono, T, Murota, N, Tanaka, H, Yagi, M, Wang, Z, Mukai, H, Itsuda, H, and Ichihashi, N. Contributions of muscle architecture and tissue properties to knee extensor force production. J Strength Cond Res 39(12): e1371-e1379, 2025-Muscular characteristics, such as muscle size, fascicle length and angle, connective tissue within the muscle, and stiffness, are related to muscle force. This study aimed to investigate the contributions of these factors for isometric contraction strength in the quadriceps muscles using multivariate analyses. Maximal voluntary isometric strength of the quadriceps at 3 different knee angles (40, 70, and 100°) in 48 adults (24 men, 23.5 ± 3.0 years) was evaluated. The cross-sectional area (CSA), fascicle length, pennation angle, echo intensity, and shear elastic modulus of the quadriceps were evaluated using ultrasonography. Simple regression analyses revealed that CSA, echo intensity, shear elastic modulus, and fascicle length were significantly related to peak torque and rate of torque development (RTD). The peak torque during isometric contraction was significantly explained by CSA as an independent variable at all knee angles (β = 0.445-0.732), but not by other variables (adjusted R2 = 0.457-0.678). The RTD as a dependent variable was explained by CSA at all angles (β = 0.491-0.702), and by fascicle length at 100° of knee flexion (β = 0.206), but not by other variables (adjusted R2 = 0.371-0.665). These results suggested that maximal isometric contraction strength was determined mainly by muscle CSA, not by other variables.

Abstract: Pinkoski, AM, Ward, P, Kluzek, S, Arundale, AJH, and Bullock, GS. Scraping the surface: a guide to data collection using web scraping in sports medicine. J Strength Cond Res 39(12): e1473-e1479, 2025-Publicly obtained injury data, which can be combined with performance data for the team and individual, have become an attractive option in sports medicine research. Publicly obtained injury data are primarily collected through reading a website's source code and converting the results into a format that can be used for further analysis, a process known as web scraping. Despite its growing popularity and public domain in which data sources exist, studies that use these methods often do not disclose their methods of extraction and are subject to replicability issues. The adoption of Open Science practices through transparency of methods and sharing of code or data sets is one such manner to ensure reproducible and meaningful results across sports medicine research and applied settings. The purpose of this article was to (a) operationalize and describe data-scraping methods, (b) describe the strengths and weaknesses of data-scraping methods in an applied sports medicine setting, and (c) provide a practical example with adjoining data and code on how to use replicable and reliable data-scraping methods in applied sport settings.

Abstract: Kaufman, CE, Szymanski, MR, Brewer, GJ, Stearns, RL, Casa, DJ, and Huggins, RA. Comparison of a body temperature wearable device with gastrointestinal thermometry during a warm-weather road race. J Strength Cond Res 39(11): e1287-e1294, 2025-To compare estimated measures of a wearable body temperature device with gastrointestinal temperature during and at the finish of a road race. Fourteen recreational runners ([ n = 9 men, n = 5 women] [mean ± SD ] age: 48 ± 14 years, V̇O 2 peak: 47.66 ± 8.21 ml·kg -1 ·min -1 ) were recruited. The wearable body temperature device and gastrointestinal temperature were measured and compared throughout the duration of the race and at race finish ( p < 0.05). During race: Poor agreement and a high, positive relationship (Lin's Concordance Correlation Coefficient [CCC] = 0.70, 95% Limits of Agreement [LOA] ± 0.94° C, r = 0.78) were noted between the wearable body temperature device and gastrointestinal temperature. No interaction was exhibited between time and device ( p = 0.087). At race finish: Poor agreement and a low, positive relationship (CCC = 0.30, 95% LOA±1.20° C, r = 0.43) were noted between the wearable body temperature device and gastrointestinal temperature. During continuous exercise in a warm weather race, the wearable body temperature device was within the acceptable limits (±0.27° C) compared with gastrointestinal temperature. The wearable body temperature device reported the widest LOA in the race finish analyses. Typical error of estimate suggests that the mean bias values may be attributed to error. Further validation is crucial in higher internal body temperatures (>39.5° C) in varying populations, environments, and intensities both pre- and postexercise Currently, this device is not acceptable for medical use or clinical diagnosis of exertional heat stroke. Medical personnel (e.g., athletic trainers, team physicians) and additional personnel (e.g., coaches, military officers, safety managers) can benefit from valid, continuous, real-time internal body temperature monitoring in the heat.

Abstract: Drayton, AM, Hamad, MJ, and Spyrou, K. The time course of postmatch physical impairments in professional soccer: A systematic review. J Strength Cond Res 39(11): e1345-e1355, 2025-Professional soccer often requires players to compete every 72 hours (h), which can lead to notable fatigue and exercise-induced muscle damage. Knowledge of postmatch impairments of physical performance can support efforts to maintain optimal performance and minimize injury risk, alongside factors such as nutrition, training structure, and sleep. This review aimed to assess the effect of single soccer matches on measures of physical performance in professional players, investigating their response at different time points: immediately, 24, 48, and 72 hours postmatch. A literature search was conducted in November 2024 on the following databases: Medline (PubMed), Web of Science, and Scopus. A total of 13 studies were eligible and included in this review. Results show that even after 72 hours, professional players still experienced significant physical impairments. Although sprint, change of direction, and technical ability had all recovered by 72 hours, studies still observed significant impairments in vertical jump ability and hamstring strength, highlighting the complexity of postmatch fatigue. Nevertheless, variations in postmatch physical impairments were observed across studies, suggesting that many factors such as baseline physical fitness levels play a determining role in the duration of these impairments. Future research is needed in elite soccer populations to better understand the extent to which specific physical fitness measures (strength, aerobic fitness, power, etc.) influence postmatch physical impairments. Nevertheless, practitioners should be aware of the varied individual recovery profiles observed in professional players, to optimize player readiness and reduce injury risk.

Abstract: Ross, S, Ripley, NJ, McMahon, JJ, and Comfort, P. Integration of a knee flexor bias or hip hinge bias resistance training program with combined high-speed running in academy soccer players. J Strength Cond Res 39(11): e1313-e1328, 2025-Strength training has been shown to mitigate risk of hamstring strain injury and enhance athletic performance. However, most training studies are focused on single exercise interventions and, therefore, lacking in ecological validity. In this study, we investigated the effects of combined resistance training and curvilinear high-speed running, with resistance training sessions having either a hip hinge bias (Romanian deadlift; RDL) or knee flexor bias (Nordic hamstring exercise; NHE), on knee flexor strength, jump, and sprint performance. In total, 37 male academy soccer players (17.1 ± 0.2 years; height, 178.3 ± 2.5 cm; body mass, 70.6 ± 0.7 kg) were randomized into 3 groups (RDL, NHE, and control) and completed 6 weeks of training. Knee flexor strength was improved in both intervention groups compared with the control ( p ≤ 0.05; g = 0.85-1.62); however, adaptations in sprint ( g = 1.14-1.44) and jump performance ( g = 1.08-1.57) were superior in the NHE group than in the RDL and control groups. The results of the study indicate that both interventions were effective in improving knee flexor strength and athletic performance, but interventions that include the NHE seem to be more effective.