Effects of Running-induced Fatigue on the Trunk-pelvis-hip Coordination Variability During Treadmill Running at Different Speeds.

Objective: The objective of this study was to examine the effects of fatigue on the coordination variability between the trunk, pelvis, and hips during treadmill running.

Methods: The kinematics data were recorded during ten successive treadmill steps running at the preferred speed and at 80% and 120% of the preferred speed. The angle segment data obtained during the running cycles were normalized to 100 data points, and they were split into ten periods. The coordination variability was calculated using the continuous relative phase (CRP) and variability (VCRP) methods for the trunk, pelvic and hip segments before and after the fatigue protocol.

Results: The repeated measures analysis of variance showed significant differences in the trunk-pelvic and trunk-hip CRPs and in the CRP variability during the last 30% of the treadmill running cycles after fatigue (p≤0.05). In addition, significant differences were observed in the pelvic-hip CRP and the CRP variability in 40% of the initial treadmill running cycles after fatigue (p≤0.05).

Conclusion: According to the results of this study, fatigue reduces coordination and increases variability. The central nervous system probably exerts more control on the distal segments for maintaining moving patterns in fatigue conditions.