Physiological and Neuromuscular Fatigue after 3-Minute Lateral Shuffle Movement at Different Speeds and Distances

This study aimed to 1) investigate and compare physiological and neuromuscular fatigue after a 3-min lateral shuffle movement (LSM) at different speeds and distances, and 2) examine the relationship between the number of changes of direction (CODs) during LSM and fatigue-related variables. Twenty male college athletes (age: 20.9 ± 1.7 yrs, body mass: 72.8 ± 8.6 kg, body height: 177.9 ± 5.6 cm; mean ± SD) performed six LSM protocols at two speeds (1.8 and 2.0 m/s) and three distances (2.5, 5 and 10 m) in random order and on separate days. The heart rate (HR), blood lactate (BLa) concentration, the rating of perceived exertion (RPE) and the countermovement jump (CMJ) were assessed and recorded before and immediately after exercise. Neuromuscular fatigue was assessed with the decline in CMJ performance (CMJ_decline). Results showed no interaction effect (speed*distance) for all variables. The distance was a significant factor influencing the HR (F = 12.663, p = 0.000, η_p ² = 0.25), BLa concentration (F = 15.357, p = 0.000, η_p ² = 0.288), CMJ_decline (F = 19.496, p = 0.000, η_p ² = 0.339), and the RPE (F = 20.149, p = 0.000, η_p ² = 0.347). Speed was also a significant factor influencing the HR (F = 6.367, p = 0.016, η_p ² = 0.144), BLa concentration (F = 10.292, p = 0.000, η_p ² = 0.213), CMJ_decline (F = 9.014, p = 0.005, η_p ² = 0.192), and the RPE (F = 9.539, p = 0.004, η_p ² = 0.201). CODs displayed moderate correlations with BLa concentration (r = 0.331, p < 0.001), CMJ_decline (r = -0.415, p < 0.001), and the RPE (r = 0.318, p < 0.001). These results suggest that physiological and neuromuscular fatigue would be greater with higher speed and shorter distance of LSM.