Between-Session Reliability of Isometric Midthigh Pull Kinetics and Maximal Power Clean Performance in Male Youth Soccer Players

Abstract Dos'Santos, T, Thomas, C, Comfort, P, McMahon, JJ, Jones, PA, Oakley, NP, and Young, AL. Between-session reliability of isometric midthigh pull kinetics and maximal power clean performance in male youth soccer players. J Strength Cond Res 32(12): 3373–3381, 2018—The aim of the study was to determine the between-session reliability of isometric midthigh pull (IMTP) kinetics and maximal weight lifted during the power clean (PC) in male youth soccer players, and to identify the smallest detectable differences between sessions. Thirteen male youth soccer players (age: 16.7 ± 0.5 years, height: 1.80 ± 0.08 m, and mass: 70.5 ± 9.4 kg) performed 3 IMTP trials, whereas only 10 soccer players performed maximal PCs. These were performed twice, separated by 48 hours to examine the between-session reliability. Intraclass correlation coefficients (ICCs) and coefficient of variation (CV) demonstrated high levels of within-session (ICC = 0.84–0.98, CV = 4.05–10.00%) and between-session reliability (ICC = 0.86–0.96, CV = 3.76–7.87%) for IMTP kinetics (peak force [PF] and time-specific force values 30–250 ms) and maximal PC (ICC = 0.96, CV = 3.23%), all meeting minimum acceptable reliability criteria. No significant differences (p > 0.05, effect size ⩽0.22) were revealed between sessions for IMTP kinetics and maximal PC performance. Strength and conditioning coaches and practitioners should consider changes of >6.04% in maximal PC and changes in IMTP kinetics of >14.31% in force at 30 ms, >14.73% in force at 50 ms, >12.36% in force at 90 ms, >12.37% in force at 100 ms, >14.51% in force at 150 ms, >11.71% in force at 200 ms, >7.23% in force at 250 ms, and >8.50% in absolute PF as meaningful improvements in male youth soccer players. Decrements in the IMTP kinetics greater than the aforementioned values could possibly be used as an indicator of neuromuscular fatigue and preparedness for training or competition.