Higher Eccentric Strength Mitigates Deceleration Performance Decline During Repeated Deceleration Tasks

Abstract

PURPOSE: This study aimed to (1) examine the relationship between eccentric strength and the ability to maintain deceleration performance following running, (2) investigate changes in deceleration kinematics during repeated deceleration tasks, and (3) explore associations between the changes in lower-limb mechanical capacities during jump tests and deceleration capacity under load. METHODS: Twenty male athletes participated. Maximal eccentric and concentric strength were assessed via back squat protocols. Participants completed the repeated acceleration-deceleration task consisting of 50 repetitions of a 10-m run followed by maximal deceleration with 45-second rest between repetitions. The ability to sustain deceleration performance was quantified as percentage change in deceleration metrics between the averaged first and last 5 repetitions. Several jump tests were performed before and after the repeated acceleration-deceleration task. RESULTS: Paired t-test showed repeated decelerations significantly increased time from peak to half-peak velocity (TT50%VPeak) (+2.55%, P = .014, d = -0.60) and decreased deceleration in this phase (DECEarly) (-3.71%, P = .012, d = -0.62). Correlational analyses revealed that eccentric strength was significantly associated with changes in TT50%VPeak (P < .01, r = -.59) and DECEarly (P = .012, r = .55). Changes in DECEarly were significantly correlated with changes in power during squat jump (P < .05, r = .53). CONCLUSIONS: Repeated deceleration actions impair early-phase deceleration performance; however, greater eccentric strength mitigates this decline. Additionally, the ability to sustain concentric mechanical capacities appears relevant to sustaining deceleration capacity. These findings highlight the importance of eccentric strength in supporting performance under repeated high-load deceleration demands.