Journal of Strength and Conditioning Research最新文献

Abstract: Freemyer, B, Takata, A, Kim, Y, and Stickley, C. Decreased hip strength leads to altered dynamic motion biomechanics in healthy female athletes. J Strength Cond Res XX(X): 000-000, 2025-The posterolateral hip muscles are essential for tasks that require dynamic ability. Weakness is associated with abnormal motions and with increased injury risk, but dynamic task performance in healthy female athletes with decreased strength is unknown. The purpose was to compare the 3-dimensional biomechanics of the drop vertical jump landing (DVJ) and side-cutting tasks across varying hip strength capabilities in healthy female athletes. Forty-six female athletes (height = 1.6 ± 0.08 m, body mass = 58.3 ± 11.9 kg, age = 16.3 ± 3.6 years) had isometric hand-held dynamometry evaluated during hip external rotation, abduction, and extension and then were categorized into low, medium, and high strength groups. Statistical parametric mapping ANOVA compared the 3-dimensional biomechanical differences between groups during the first landing of a DVJ and a side-cutting maneuver across ground contact at an alpha level of p ≤ 0.05. Strength was different between the groups across the 3 measures (all

Abstract: Verheij, CTM, Meijers, V, Smith, J, and Hartman, E. On the relationship between physical fitness, perceived athletic competence, and physical activity intensity levels in 8- to 12-year-old children. J Strength Cond Res 40(1): e76-e84, 2026-This study investigated relationships between physical fitness (PF) and physical activity (PA) and the mediating role of perceived athletic competence (PAC). The cross-sectional study involved 180 typically developing children (45% boys; 10.0 ± 1.1 years). Cardiorespiratory and musculoskeletal fitness were measured with the European Test of Physical Fitness, PAC with the Self-Perception Profile for Children, and PA with accelerometry. Physical activity was analyzed separately for sedentary behavior, light PA, moderate PA (MPA), and vigorous PA (VPA). Path analysis in AMOS examined model 1, which assessed the relationship between PF and PA, and model 2, which evaluated the mediating role of PAC in the PF-PA relationship. The results from model 1 showed weak positive associations between both cardiorespiratory and musculoskeletal fitness with MPA and VPA ( β = 0.215-0.250, p < 0.05). When PAC was added as a mediator in model 2, the significant relationship between musculoskeletal fitness and VPA became nonsignificant, while the relationships between musculoskeletal fitness and MPA and between cardiorespiratory fitness and both MPA and VPA remained weak. In addition, PAC mediated the relationship between musculoskeletal fitness and MPA and VPA in the total population ( β = 0.064-0.076, p < 0.01) and in boys, while in girls, its mediating role was limited to VPA. In conclusion, interventions seeking to improve PA should focus on improving PF and PAC, as a higher cardiorespiratory fitness level might directly enhance children's ability to engage in MPA and VPA, and a higher musculoskeletal fitness level might stimulate engagement in MPA and VPA through PAC.

Abstract: Varesco, G, Germain, M, Szocs, S, Martin, A, Toussaint, P-M, and Simonelli, G. Exploring the relationship between sleep hygiene recommendations and outcomes in sleep, fatigue, and cognitive performance among student-athletes. J Strength Cond Res 40(1): 48-55, 2026-Student-athletes often neglect sleep because of academic and training demands, highlighting the value of interventions targeting poor sleep habits. However, sleep hygiene research remains limited to individualized approaches, limiting reproducibility and posing challenges for implementation in large groups, such as collegiate sports teams. In this 4-week study, we assessed the sleep health of an elite collegiate Canadian football team through questionnaires (week 1). Players with poor sleep habits (Pittsburgh Sleep Quality Index > 5; 24 out of 64) participated in a 2-week sleep hygiene intervention. After a familiarization session (week 2), they completed 2 weeks of sleep assessment (actigraphy, sleep diary) and a post-training test, including a fatigue 10-cm visual analog scale, psychomotor vigilance task (PVT), and paced visual serial addition test (PVSAT). Subjects were unaware to be selected based on their poor sleep habits. After week 3, athletes received feedback on poor sleep habits and standardized written, evidence-based sleep hygiene recommendations. They were asked to comply with these recommendations before repeating experimental procedures at the end of week 4. Improvements were observed only in perceived total sleep time (sleep duration; 7:43 ± 1:29 vs. 8:03 ± 1:34 h:mm, p = 0.045) and PVSAT performance (1.44 ± 1.8 vs. 1.36 ± 1.63 seconds, p = 0.004), while PVT speed decreased (3.6 ± 0.4 vs. 3.5 ± 0.4 Hz, p = 0.043). Objective sleep duration (6:53 ± 1:19 vs. 7:04 ± 1:19 h:mm, p = 0.21), fatigue (6 ± 2.1 vs. 5.8 ± 2.1 AU, p = 0.55), and other outcomes remained unchanged ( p > 0.37). These results indicate that unsupervised and standardized sleep hygiene recommendations were not associated with changes in sleep habits, with changes in cognitive performance and fatigue level that could not be reconducted to better sleep.

Abstract: Kvorning, T, Karkov, DS, Luno, CS, Dinesen, NM, Jørgensen, AN, Gejl, KD, Blazevich, AJ, and Aagaard, P. Morning-based resistance exercise improves afternoon jumping performance, stretch-shortening-cycle muscle power, and lower limb stiffness in top-level ice hockey players. J Strength Cond Res 40(1): e26-e31, 2026-Precompetition training (PCT) performed as nonexhaustive bouts of morning-based resistance exercise (e.g., resistance priming) may positively affect afternoon physical performance. Specifically, experimental evidence points toward improved force- and power-related performance. The present study aimed to examine the effect of a morning PCT session on afternoon mechanical muscle function, as reflected by changes in maximal isolated isometric knee extensor (KE) strength (maximal voluntary contraction), and KE rapid force capacity (rate of force development: RFD), countermovement jump (CMJ) kinematics and kinetics, and lower limb stiffness (LLS). Fifteen Danish elite ice hockey players from the U20 National Team (18-20 years) performed (a) a PCT test day consisting of a back squat-lift session of 4 sets of 3 repetitions, with a maximal intentional speed at 50, 65, 75, and 85% 1 repetition maximum, respectively, in the morning (9:00 hours) followed by CMJ and KE testing in the afternoon (15:00 hours), and (b) a control (CON) test day consisting of afternoon (15:00 hours) testing only. Results showed that enhanced stretch-shortening-cycle (SSC) muscle function was observed during CMJ testing after PCT compared with CON (p ≤ 0.05), as evidenced by increases (p < 0.05) in maximal jump height (+3.5% [0.5-6.5]), peak vertical ground reaction force in the descending phase (+5.1% [0.3-9.9]), take-off impulse in the ascending phase (+1.6% [0.2-3.1]), LLS (+23.1 [-4.3 to 50.6]), and mean ascending take-off power (+4.8% [1.7-7.9]). In contrast, PCT did not elicit changes in KE strength or RFD. In conclusion, morning-based PCT in the form of lower-body resistance exercise improves lower limb SSC muscle function later in the day in this cohort of high-level athletes.

Abstract: Healis, J, Adams, KJ, and Lawrence, MM. Trends in American female youth and junior weightlifting performance from 2015 to 2023. J Strength Cond Res 40(1): 56-67, 2026-This investigation assessed performance trajectories of American Youth and Junior female weightlifters in the snatch (SNT), clean and jerk (CJ), and total (T) from 2015 to 2023, using results from sanctioned USA Weightlifting events. Subjects ( N = 960-2,245) were ≤20 years old at initial competition. Performance was evaluated using strength-to-mass (SM) ratios, tracking the highest SM ratios, and allometric scaling in 3-month timeframes using each athlete's best total per timeframe for the first 3 years and 6-month timeframes over the study period (∼9 years). Performance was analyzed using percentage changes and Cohen's d effect sizes (ES). For 3-month timeframes, the largest initial improvements were between 3 and 6 months for the SNT (12.44%; ES = 0.00), CJ (11.12%; ES = -0.01), and T (11.50%; ES = 0.00). For 6-month timeframes, large improvements occurred from 6 to 12 months for SNT (SM = 0.80 ± 0.20 kg, 14.91%, ES = 0.11), CJ (SM = 1.03 ± 0.25 kg, 13.34%, ES = 0.10), and T (SM = 1.82 ± 0.45 kg, 13.87%, ES = 0.11) with potential performance plateaus observed around year 7 (78-84 months) for SNT (-0.25%, ES = 0.04), CJ (-2.68%, ES = 0.07), T (-1.90%, ES = 0.07). Allometric results supported these trends, showing similar peak timing and magnitude. Reduced participation rates from the first 3/6-month timeframes ( N = 2,245) to the next 6/12-month timeframes ( N = 970-1,209) continued until the final timeframe, which cannot be strictly attributed to aging out. Compared with data before 2015, weightlifters had higher initial performances, greater early gains, and potentially earlier plateaus. This suggests that evolving coaching methods improved performance, but targeted strategies are needed to sustain engagement and overcome plateaus in later training stages.

Abstract: Amdi, CH, Spence, A-J, Helms, ER, and McGuigan, MR. Exploring exercise specificity in powerlifting: A survey of powerlifters' training practices and demographic influences. J Strength Cond Res 40(1): 76-89, 2026-This study aimed to examine powerlifters' training practices related to exercise specificity. A total of 548 powerlifters responded to an anonymous online survey, with 401 completing all questions. On average, lifters trained 4.25 times per week and performed the competition-style squat, bench press, and deadlift 1.64, 2.48, and 1.37 times per week, respectively-typically using 1-7 repetitions at ratings of perceived exertion (RPEs) of 6-10. Almost all lifters (>97.5%) incorporated varied practice, including barbell variations (squat: 1.50×, bench press: 2.14×, deadlift: 1.26×) and accessory exercises (squat: 1.73×, bench press: 2.46×, deadlift: 1.72× per week). These were generally performed with 4-7 repetitions at RPE 6-8.5 for variations, and ≥8 repetitions at RPE 6-10 for accessories. The most common barbell variations involved slower eccentric phases, added or prolonged pauses in the bottom position, among others. Most lifters modified how they programmed (i.e., volume, frequency, relative-load, or RPEs) the competition lifts (88.2%), barbell variations (71.7%), and accessory exercises (62.3%) as competition approached, whereas 35.1-45.7% changed exercise selection depending on competition proximity. However, 49.0-58.7% maintained consistent exercise selection throughout competition periods. These programming decisions were influenced by athlete characteristics such as gender, use of supportive equipment, age, weight class, relative strength, and training status. Collectively, these findings indicate that varied practice is common in powerlifting.

Abstract: Achermann, BB, Drewek, A, and Lorenzetti, SR. Acute effect of the bounce squat on ground reaction force at the turning point and barbell kinematics. J Strength Cond Res 40(1): 1-8, 2026-The free-weight back squat is a key exercise for developing lower-body strength, with variations that influence muscle activation and performance. The bounce squat, a variation involving a controlled bounce, increases the eccentric velocity at the squat's bottom. In this study, we aimed to investigate the effects of the bounce squat, descent velocity, and load on barbell kinematics and ground reaction force (GRF) during back squats. In addition, we explored the prediction of GRF from barbell kinematics. Overall, 29 participants completed 2 sessions, including bounce and no-bounce squats. Session 1 was focused on the load (70 and 80% 1RM), whereas session 2 examined the descent velocity (fast vs. slow). Data were analyzed using linear mixed-effects models ( p = 0.05). Bounce squats increased the GRF significantly by 19 and 22% (sessions 1 and 2, respectively). Furthermore, it increased the peak velocity in the early concentric phase (Vpeak1) and reduced it in the late concentric phase (Vpeak2). Higher loads significantly reduced the mean concentric velocity (Vmean), minimum velocity, Vpeak1, and Vpeak2, and minimally enhanced the GRF. Faster descent enhanced Vmean and Vpeak2 without affecting the GRF or Vpeak1. These findings emphasize balancing performance with musculoskeletal stress and underscore the importance of accurate technical execution of back squats. Supporting factors such as descent velocity and load should be tailored to preserve the optimal technique. Predicting GRF from barbell kinematics highlights its potential for monitoring squat performance.

Abstract: Morimoto, E, Matsui, M, Mori, S, Kumakura, T, Konishi, M, Michinobu, R, Fukuda, T, Takemura, M, and Kosaki, K. Comparison of brachial artery endothelial function in the dominant arm between male college baseball pitchers and fielders. J Strength Cond Res 40(1): 106-111, 2026-Although structural changes caused by exercise-induced vascular adaptation have been reported in baseball players, current evidence in the literature concerning vascular function remains limited. This cross-sectional study aimed to determine whether vascular endothelial function in the brachial artery of the dominant arm differed between university baseball pitchers vs. fielders. Ninety baseball players participated in this study. Brachial artery diameter and vasodilator function were measured in the supine position for each subject using an ultrasound imaging system. Shoulder joint range of motion and muscle strength were measured in supine and prone positions. Compared with the fielders, the pitchers had a decreased mean flow-mediated dilation (FMD) values (7.5% ± 2.5 vs. 10.6% ± 4.0%, p < 0.001) but significantly higher values for range of motion regarding external rotation (ER) of the shoulder joint (119.8 ± 8.5° vs. 115.7 ± 7.8°, p = 0.035), ER muscle strength (7.6 ± 2.2 N vs. 6.2 ± 2.0 N , p = 0.009), and baseline brachial artery diameter (4.2 ± 0.4 mm vs. 4.0 ± 0.4 mm, p = 0.010). Simple correlation analysis showed a negative correlation among FMD values, shoulder joint internal rotation strength, and ER range of motion. These findings indicate that functional exercise-induced vascular adaptations occur in the brachial artery of pitchers, indicating a possible role for position-specific demands in vascular remodeling.

Abstract: Sanchez, KJ, Baruch, T, Ross, KA, Coburn, JW, Costa, PB, Orr, RM, Dawes, JJ, and Lockie, RG. Coronary artery calcium status, body composition, blood lipids, and fitness among firefighters participating in a health and wellness program. J Strength Cond Res 40(1): e95-e103, 2026-Cardiovascular disease (CVD) is prevalent among firefighters. Coronary artery calcium (CAC) can contribute to the identification of CVD risk, but there has been limited analysis in firefighters. This study investigated body composition, blood lipid, and fitness test differences in firefighters with normal (CAC-N) and abnormal (CAC-A) CAC. Relationships between these health and fitness variables and CAC status were also derived. Archival data from 45 male firefighters were examined. Data included age, height, body mass, body mass index, body fat mass, lean body mass, waist-to-hip ratio, blood lipids (triglycerides, low-density lipoproteins, high-density lipoproteins, total cholesterol), grip strength, vertical jump (VJ), plank, push-ups, resting heart rate, systolic and diastolic blood pressure (BP), and estimated maximal aerobic capacity (V̇ o2 max). Firefighters were screened and grouped as CAC-N (CAC = 0; n = 35) and CAC-A (CAC > 0; n = 10). Independent samples t-tests or Mann-Whitney U -tests determined between-group differences. Pearson's correlations determined relationships between the binary variable of CAC status with the other variables. There were no significant between-group differences in any variable. The CAC-N group had a lower systolic BP than the CAC-A group, with a moderate effect ( p = 0.080, d = 0.893). Systolic BP also correlated with CAC status ( r = 0.355; p = 0.017). The CAC-N group had 9-14% better VJ and V̇ o2 max than the CAC-A group, which had small effects ( p = 0.050-0.110, d = 0.555-0.584). Body composition, blood lipids, and fitness generally did not differentiate or relate to CAC status. Apparently fit and healthy firefighters may have underlying CVD risk factors such as higher CAC. Health and wellness programs should be multifaceted, including exercise and medical screening.

Abstract: Rebelo, A, Comfort, P, Harry, JR, and Ripley, N. Drop landing as a neuromuscular fatigue assessment: A submaximal alternative to traditional monitoring methods. J Strength Cond Res 40(1): e17-e25, 2026-Neuromuscular fatigue monitoring is important for optimizing performance and reducing injury risk in elite athletes and tactical personnel. Traditional assessments-such as the countermovement jump (CMJ) or the isometric mid-thigh pull-require maximal effort, which may be inconsistent because of motivation, external constraints, or strategic load management. As an alternative, drop landing emphasizes eccentric control and can be performed submaximally, potentially reducing variability associated with effort while still providing insight into neuromuscular fatigue. The aim of this study was to examine whether fall height, landing phase duration, landing performance index, and average impact force can indicate post-training neuromuscular fatigue in elite volleyball players. Fourteen players (age: 29.18 ± 6.24 years; height: 1.95 ± 0.08 m; body mass: 95.20 ± 7.83 kg) performed drop landings at 70, 85, and 100% of their maximal CMJ height before and after an 82-minute volleyball training session. Test-retest reliability was strong (intraclass correlation coefficient = 0.71-0.98, 95% CI; CV < 6%). Post-training, fall height decreased at 100% ( g = 0.31, p = 0.003), while landing phase duration increased at 100% ( g = 0.55, p = 0.015). Average impact force declined at all drop heights, with significant reductions at 85% ( g = 0.34, p = 0.004) and 100% ( g = 0.35, p = 0.042), suggesting a more softer landing strategy. Landing performance index decreased at 85% ( g = 0.40, p = 0.019) and 100% ( g = 0.58, p = 0.002). These results suggest fatigue-induced changes in force attenuation strategies. Future research should examine whether similar adaptations occur between the landing phase of a maximal CMJ and a 100% drop landing under fatigue.