Abstract 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 40(11): 1356–1363, 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]; η p 2 = 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 R 2 > 0.53 for both), whereas a theoretical maximal velocity showed a weak association (adjusted R 2 = 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.
Abstract Martínez-Hernández, D, Jones, PA, Oliva-Lozano, JM, and Harper, DJ. Maximum deceleration is related to players' ability to repeat high-intensity decelerations in a match in female professional soccer players. J Strength Cond Res XX(X): 000–000, 2026—The aim of this study was twofold; First, to investigate positional differences in high-intensity decelerations (HID; < −3 m·s −2 ) and very high-intensity decelerations (VHID; < −4 m·s −2 ) in elite female soccer players. Second, to examine relationships between maximum deceleration (D Max ) and the frequency of HID and VHID throughout competitive match play, reflecting players' capacity to perform these actions repeatedly. Twenty-four professional female outfield players (189 match files) from an English Women's Superleague club were tracked across 27 matches using 10-Hz Global Positioning System devices. Differences in deceleration metrics (D Max , HID, VHID) across positions were analyzed using 1-way analysis of variance and Bonferroni post hoc tests. Pearson's correlations assessed relationships between D Max , HID, and VHID across playing positions. Significant positional differences were observed. Central defenders had the lowest D Max and performed fewer HID and VHID actions than other positions, whereas central midfielder recorded the highest HID values. Maximum deceleration showed moderate-to-large correlations with HID ( r = 0.35) and VHID ( r = 0.52). Positional and individual variations influenced the strength of these relationships. This study provides novel evidence that maximal deceleration capacity is an important neuromuscular performance quality that distinguishes playing positions in elite women's soccer, with moderate-to-large associations with the ability to perform repeated HID and VHID supporting its relevance to match performance, particularly at higher intensities. These findings suggest that D Max may be an important quality to target through training, with potential implications for repeated deceleration performance. Practitioners should implement position-specific assessments and interventions to optimize deceleration capacity, especially as modern game demands continue to evolve.
Abstract Hernandez-Davo, JL, Sabido, R, Asencio, P, and Boullosa, D. Comparison between concentric-only and eccentric-concentric load-velocity relationships and its derived parameters in the jump squat and bench press throw exercises. J Strength Cond Res XX(X): 000–000, 2026—The aim of this study was to analyze 2 different load-velocity (L-V) assessment protocols (concentric-only [CON] vs. maximal intended eccentric velocity [MAX]) on the L-V relationship in jump-squat (JS) and bench press throw (BPT) exercises, 18 men performed the L-V relationship assessments with loads representing 20, 40, 60, and 80% of one repetition maximum (1RM) on 2 different days. Reliability was assessed using intraclass correlation coefficient (ICC) and coefficient of variation (CV%). The mean propulsive velocity (MPV) was used to establish individual L-V profiles, their derived parameters (L 0 and V 0 ), and estimated 1RM values in back-squat and bench press exercises. Maximal intended eccentric velocity condition showed high reliability (ICC: 0.70–0.87: CV: 4.2–11.2%), whereas CON condition showed moderate-to-high scores (ICC: 0.61–0.86; CV: 4.8–10.4%). The mean propulsive velocity values were significantly higher in the MAX condition at all loads in the JS (8.9–10.9%) and at all loads except the 20% 1RM in the BPT exercise (6.1–23.3%). When using the MAX condition, L 0 values were higher in the BPT exercise (5%), and V 0 was greater in both the JS (9.0%) and BPT exercises (3.4%). The estimated 1RM value was higher in the MAX condition for both the squat (124.1 vs. 117.8 kg) and the bench press exercises (89.2 vs. 83.9 kg). High-velocity eccentric actions led to significantly higher MPV values, without compromising reliability values. The L-V profile and their derived parameters are substantially affected by eccentric velocity instructions. Standardized protocols using maximal eccentric velocities are suitable to assess athletes' maximal neuromuscular performances with reliable L-V profiles, which may complement the information obtained through the habitual CON protocol.
Abstract Vatne, EA, Cencer, D, Vatne, M, Pulvermacher, K, Saenz, C, Kraemer, WJ, Robinson, B, Jones, P, Quebedeaux, N, Sprague, R, Dial, M, Carpenter, T, and Hagen, J. Relationship between objective measures of sleep and nocturnal cardiovascular physiology and swimming performance in collegiate female athletes: A Bayesian analysis. J Strength Cond Res XX(X): 000–000, 2026—There is substantial evidence that sleep influences athletic performance; however, relationships with real-world competition outcomes remain unclear. Therefore, the purpose of this study was to explore the associations between objectively measured sleep, nocturnal cardiovascular physiology on the night before competition, and swim performance in female collegiate athletes. Female swimmers ( n = 11) who wore a sleep monitoring device the night before competition, competed in the 200-yard freestyle (short course yard), and had ≥21 of 28 prior nights of valid data were included. Sleep metrics included total sleep time (TST), time in bed (TiB), and sleep efficiency (SE), whereas nocturnal cardiovascular metrics included heart rate variability (HRV) and resting heart rate (RHR) standardized as individualized z -scores. Race times were obtained from a publicly available database. Bayesian linear mixed-effects models estimated posterior probabilities of performance improvement. Results indicated a high probability that greater TST and TiB were associated with faster race times, with substantial support for improvements of at least 1 second per additional hour of sleep. In contrast, SE, HRV, and RHR showed low posterior evidence of meaningful associations with performance. These findings extend prior sleep and performance literature that has been confined to proxy assessments of athletic performance in controlled settings to real-world competition that should inform athlete education, emphasizing the importance of sufficient sleep opportunity and duration before competition.
