Walking on a treadmill improves the stride length-cadence relationship in individuals with Parkinson's disease

Background: The gait pattern in Parkinson's disease (PD) is characterized by a deficit in the internal regulation of stride length (SL), while the control of cadence (Cad) remains intact. The use of the treadmill as a gait rehabilitation tool has provided novel options for treatment of gait impairments in PD. However, it remains unclear whether walking on the treadmill changes the stride length-cadence relationship (SLCrel) in PD. The purpose of the present study was to analyze the SLCrel in PD subjects walking on a treadmill vs. overground, and to further compare the SLCrel to that of age-matched healthy subjects. Methods: Fifteen PD subjects and fifteen age-matched controls walked overground and on a treadmill at five different self-selected speeds. Gait speed, SL and Cad were recorded at each self-selected speed. A linear regression analysis was conducted to explore the SLCrel and to determine the slope and intercept for each participant. Results: PD subjects showed a lower intercept than control subjects when walking both overground and on a treadmill (F = 8.51, p = 0.007). In comparison with walking overground, walking on a treadmill resulted in a significant increase in the intercept in both PD and control groups (F = 12.17, p = 0.002). There were no significant differences in the slope of the SLCrel. Conclusion: PD subjects are able to improve the internal regulation of SL when walking on a treadmill. Our results confirm the potential therapeutic effects of treadmill training for gait rehabilitation in PD and suggest that the mechanisms underlying the positive effects of treadmill training on PD subjects are sustained.