Walking Gait Propulsive Force In Ambulatory Patients With Parkinson's Disease

PURPOSE: Neuromuscular control and execution of gait is altered in Parkinson’s disease (PD). Although several studies have identified a decrease in walking propulsive force in subjects with PD, interventional studies to restore, maintain, or slow the decline in propulsive force production are lacking. The purpose of the present study was to determine the effect of a 12-week overground locomotor training (OLT) program on propulsive force generation in ambulatory patients with mild to moderate PD. METHODS: Pre and post OLT, participants walked across forceplates (1000 Hz) at their self-selected preferred walking speed for 10 trials. Measures of propulsive force included the peak positive anterior ground reaction force (AGRF) (Newtons), the rate of rise (ROR) (seconds) of the AGRF, the push-off impulse (Newton-seconds), and the push-off duration (seconds) during over ground walking. Walking speed was also assessed (meters/second). RESULTS: Eleven participants with PD (7 Male; Age: 69.7 ± 4.9 years; H&Y: 1-3) completed 24, 60-minute sessions of OLT. Paired t-tests indicated there was not a significant difference in the average peak AGRF pre OLT (M = 141.43, SD = 34.02) compared to post OLT (M = 139.01, SD = 31.90), t (10) = .608, p = .557, d = .183; a significant difference in the average ROR pre OLT (M = .28, SD = .035) compared to post OLT (M = .24, SD = .054), t (10) = 2.92, p = .015, d = .879; a significant difference in the mean push-off impulse pre OLT (M = 31.36, SD = 7.59) compared to post OLT (M = 27.29, SD = 8.59), t (10) = 2.62, p = .026, d = .789; a significant average difference in the preferred walking speed pre OLT (M = 1.36, SD = .176) compared to post OLT (M = 1.44, SD = .124), t (10) = -2.75, p = .023, d = .869. A Wilcoxon signed-rank test indicated there was a significant difference in the average push-off duration pre OLT (M = .46, SD = .041) compared to post OLT (M = .41, SD = .084), Z = -2.312, p = .021, r = .697. CONCLUSIONS: Peak AGRF attained by participants did not change after OLT; however, the ROR of the AGRF, was significantly decreased. In addition, walking speed was significantly increased. This finding suggests that OLT may influence the rate of muscular force development used to generate propulsive force and that the rate of force production is an important understudied factor in characterizing propulsive force in ambulatory patients with PD.