Relationships between knee and ankle strength and horizontal deceleration performance at different sprint distances in multi-directional sports athletes.

The aim of this study was to investigate the relationships between knee and ankle strength and horizontal deceleration performance following different sprint distances. Fifty-seven (n = 41male, n = 16 female) youth team-sports athletes completed: a) 5-m and 10-m horizontal deceleration ability (HDA) tests; b) concentric (60°/s, 180°/s) and eccentric (30°/s) relative peak torque (PT) measurements of the knee extensor (KE) and flexor (KF) muscles and the ankle plantarflexion (APF) and dorsiflexion (ADF) muscles in an isokinetic dynamometer. Pearson's correlation coefficients revealed that concentric at 60°/s and eccentric at 30°/s KE were mostly related to deceleration performance both in HDA5-m (r = -0.50 to -0.61, p < 0.05) and HDA10-m tests (r = -0.50 to -0.63, p < 0.05). Moreover, a significant correlation was observed between concentric APF and average deceleration (DECavg) measured from HDA5-m test in both the dominant leg (DL) and non-dominant leg (NDL) (r = -0.52 to -0.53, p < 0.05), but not to 10-m horizontal deceleration performance. The current results indicate that deceleration performance varies in its demands on knee and ankle strength across different sprint distances. Athletes who frequently decelerate over short distances should focus not only on strengthening their knee strength but also on prioritising ankle strength.