Author(s): LYU, M., CHEN, Z., TANG, R., DING, L., DENG, S., ADAMS, R., HAN, J., LI, Y., Institution: SHANGHAI UNIVERSITY OF SPORT SCHOOL OF ATHLETIC PERFORMANCE, Country: CHINA, Abstract-ID: 301

INTRODUCTION:
To determine how lateral shuffle (LS) induced fatigue affects ankle proprioception and countermovement jump (CMJ) performance.
METHODS:
Eighteen male college athletes (age: 21.3±1.8 yrs, body mass: 72.8±8.5 kg, height: 177.4±5.8 cm; mean±SD) performed 6 modes of a repeated LS protocol with 2 distances (2.5, 5m) and 3 speeds (1.6, 1.8, and 2.0 m/s) on separated days. The number of change of directions (CODs) in each protocol was recorded. Ankle inversion proprioception (AIP) was measured using the active movement extent discrimination apparatus (AMEDA) after LS. Lower limb neuromuscular performance was evaluated by CMJ. Fatigue measures, including Blood lactate (BLa), rating of perceived exertion (RPE), and heart rate (HR), were assessed before and after LS.
RESULTS:
LS-induced fatigue was consistently evident in BLa (F =23.109, p ≤ 0.001, η2= 0.405), HR (F =4.575, p < 0.05, η2= 0.119), and RPE (F =8.426, p ≤ 0.001, = 0.199), increasing with shorter distance and faster speed. RM-ANOVA showed a significant distance main effect on both AIP (F=7.351, p < 0.01, η2= 0.178) and CMJ (F=5.265, p < 0.05, η2= 0.134), but the speed main effect was only significant on CMJ performance (F =5.265, p ≤ 0.001, η2= 0.273), not AIP scores (p = 0.87). While CMJ performance was significantly correlated with Bla, HR and RPE (r range from -0.62 to -0.32, all p ≤ 0.001), AIP was only correlated with CODs (r=-0.251, p <0.01).
CONCLUSION:
In LS, shorter distance, regardless of speed, was associated with worse AIP, whereas subsequent CMJ performance was affected by both LS distance and speed. Here, AIP performance was not related to physiological fatigue, but CMJ performance was. These results suggest that LS movements affect proprioceptive input and muscular output differently; and that these two aspects of neuromuscular control are affected by physiological fatigue to varying degrees. These findings have implications for injury prevention and performance enhancement.