Measures of Strength and Jump Performance Can Predict 30-m Sprint Time in Rugby Union Players

Furlong, L-AM, Harrison, AJ, and Jensen, RL. Measures of strength jump performance can predict 30-m sprint time in Rugby Union players. J Strength Cond Res 35(9): 2579–2583, 2021—Performance fitness monitoring often include jumping, sprinting, tests, but repeatability relationships between these measures are unclear. The level interindividual variability their predictive capabilities also unknown. This study examined the reliability of, relationship between, countermovement (CMJJH), squat (SJJH), rebound (RBJJH) heights, contact (RBJCT), estimated 1 repetition maximum back relative to body mass (SQBM), reactive index (RSI) subelite, semiprofessional Measurement was very good, with high average intraclass correlation coefficients (≥0.9) low coefficient variation (<10.1%). All variables were significantly (p < 0.01) correlated each other (r > 0.575), except for SQBM (only related CMJJH, r = 0.621) RBJCT RSI, −0.727). SJJH strongest most consistent predictors 30 m (R 0.754 ± 0.081; SEE 0.166 0.025), magnitude observed across group during bootstrapping. Cross-validation showed a mean difference actual predicted times equivalent 0.22% m. These results support importance multiple aspects training players improving short-duration sprinting activities, highlight individual nature importance. power be used short by conditioning professional.