Effects of loading the unaffected limb for one session of locomotor training on laboratory measures of gait in stroke

BACKGROUND: Walking following stroke involves compensatory strategies by the unaffected leg to cope with the deficits in the hemiparetic leg. Recently, training paradigms based on the principles of task-oriented repetitive exercise have provided a valuable insight regarding the influence of restraining compensatory movements to improve motor performances. We investigated changes in the walking movements of each lower extremity after weighting the unaffected leg. METHODS: Ten individuals early after a stroke (range: 3-7 months) who were able to walk 10 m with no aids, participated to this study. Subjects were instructed to walk on a treadmill with an external mass attached around the non affected ankle during a single session. The short-term effects on gait performance were quantified by a 3D-gait analysis system before, immediately after and 20 min after the walking technique. FINDINGS: A one factor repeated measures model revealed that stroke participants significantly improved in walking speed (P<0.001), step length (P<0.01) and cadence (P<0.01). Weight-bearing on the paretic leg increased (P<0.01) along with kinematic modifications including greater hip and knee excursion. When the mass was removed, these adaptations were maintained 20 min later. INTERPRETATION: Preliminary findings suggest that even brief gait training using a treadmill with a restrictive weight placed on the distal extremity of the non-hemiplegic lower limb can improve laboratory measures of gait ability in a sample of stroke subjects. Future studies must evaluate the effect of this technique in longer-term locomotor retraining.