Effect of Lower Limb Muscle Fatigue on Ground Reaction Force Components During Landing in People With Nonspecific Chronic Low Back Pain
in Journal of Sport RehabilitationContext: The link between landing parameters and lower limb muscle fatigue in association with chronic low back pain (CLBP) is not well understood. Objective: To examine the effects of fatigue on the ground reaction force components during landing in people with nonspecific CLBP. Design: Quasi-experimental study. Setting: Clinical biomechanics laboratory. Participants: A total of 44 subjects were equally divided into a healthy group and a group with CLBP. Main Outcome Measures: The ground reaction force along anterior–posterior (y) and medial–lateral (x) and vertical (z) axes, time to peak (TTP), the rate of force development, and impulses for all axes were calculated. A repeated-measures analysis of variance (group × fatigue) was used to compare the data among groups. Results: In the unfatigued conditions, the amplitudes of Fy3, Fz2, and TTP of Fy1, Fy2, Fz1, Fz2, Fz3, Fz4, rate of force development in Y in the CLBP subjects are significantly different than those in the healthy subjects (P < .05). In the fatigued conditions, the amplitudes of Fz2, Fz3, Fz4, and TTP of Fy2, Fy3, Fy4, Fz2, impulses of X2, Z in the CLBP group were significantly different than those in the healthy subjects (P < .05). Within-group comparisons of measured Fx1, Fy1, Fy2, Fz2, Fz4 and TTP of Fx1, Fy1, Fy2, Fz2, Fz3, Fz4, impulses of X2, z were significantly different from prefatigue to postfatigue in the healthy group (P < .05). Within-group comparisons of measured Fx1, Fy1, Fz1, Fz2 and TTP of Fx5, Fz1, impulses of X2 were significantly differed from prefatigue to postfatigue in the CLBP group (P < .05). Conclusions: It seems that TTP of ground reaction force variables in CLBP may have clinical values for rehabilitation. Muscle fatigue altered landing performance. However, patients with CLBP will respond differently to lower-extremity fatigue. These altered variables in patients with low back pain are the cause of future injuries or lower-extremity injuries that need to be addressed in further studies.
Jalalvand is with the Department of Sport Biomechanics, Hamedan Branch, Islamic Azad University, Hamedan, Iran. Anbarian is with the Department of Sport Biomechanics, Bu-Ali Sina University, Hamedan, Iran.
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