Effect of Intermittent Vs. Continuous Walking on Kinematic Variables in Persons with MS: Partial Results of an Ongoing Study

Background:  Previous research has shown that persons with MS can walk longer distances with less fatigue when the walking is performed intermittently rather than continuously. The specific reasons for this improved performance have not been examined. Recent articles have examined biomechanical factors in MS gait. Biomechanical factors may further explain the mechanism by which persons with MS walk longer distances intermittently than continuously.

Objectives: The purpose of this study was to determine if kinematic factors could explain the difference between these two walking conditions. We hypothesize that intermittent walking will result in different kinematic measurements than continuous walking.

Methods: Using a randomized crossover design, ambulatory subjects were recruited from MS practices and support groups. In the continuous condition, subjects walked for 6 minutes continuously. In the intermittent condition, subjects walked for three 2-minute bouts with a seated 2-minute rest between each 2-minute walk. Kinematic data was collected using the Protokinetics Zeno Walkway. Distance walked, as well as kinematic measures, were measured at 1-minute intervals for each condition. 

Results: Six subjects (Mean EDSS 4.2) have so far completed the study. In the intermittent condition, the L/R ratio of percent stance time at minute one compared to minute six was more equal than in the continuous condition (p=.054). Subjects walked significantly farther in the intermittent condition than in the continuous condition (1215’ vs. 1148’, p=.05.)

Conclusions:  Analysis of preliminary results indicates that stance time became less symmetrical in the continuous condition than in the intermittent condition as the distance walked increased. This may provide a possible kinematic explanation for the difference in distances walked in these two conditions. It is hoped that with increasing the sample size, a more complete explanation for the differences seen between the two walking conditions will emerge. If this trend continues to be seen in a larger sample, it would suggest that gait asymmetry may underly decreased gait endurance in persons with MS, and that interventions to maintain gait symmetry might improve gait endurance.