Effects of gait training with horizontal impeding force on gait and balance of stroke patients

Different functional networks underlying human walking with pulling force fields acting in forward or backward directions

Walking with pulling force fields acting at the body center of mass (in the forward or backward directions) is compatible with inclined walking and is used in clinical practice for gait training. From the perspective of known differences in the motor strategies that underlie walking with the respective force fields, the present study elucidated whether the adaptation acquired by walking on a split-belt treadmill with either one of the force fields affects subsequent walking in a force field in the opposite directions. Walking with the force field induced an adaptive and de-adaptive behavior of the subjects, with the aspect evident in the braking and propulsive impulses of the ground reaction force (difference in the peak value between the left and right sides for each stride cycle) as parameters. In the parameters, the adaptation acquired during walking with a force field acting in one direction was transferred to that in the opposite direction only partially. Furthermore, the adaptation that occurred while walking in a force field in one direction was rarely washed out by subsequent walking in a force field in the opposite direction and thus was maintained independently of the other. These results demonstrated possible independence in the neural functional networks capable of controlling walking in each movement task with an opposing force field.

Are biomechanical strategies to perform functional activities different between individuals with subacute and chronic stroke?

OBJECTIVE

To evaluate if the capacity to perform functional mobility activities change within the first year post-stroke using the Timed "Up and Go" Assessment of Biomechanical Strategies (TUG-ABS).

METHODS

A cross-sectional study was conducted with thirty-eight stroke individuals. A motion analysis system was used during the Timed "Up and Go" (TUG) test to evaluate the following activities: sit-to-stand, gait, turn, and stand-to-sit. Kinematic variables related to each activity were obtained in addition to TUG-ABS scores. The ability to perform the activities was compared between subacute (up to 3 months post-stroke, n = 21) and chronic participants (4 to 12 months post-stroke, n = 17) using Mann-Whitney U tests (α= 5%).

RESULTS

Results were expressed as median difference (MD) and 95% confidence intervals (95% CI). TUG-ABS scores: Sit-to-stand (MD = 0, 95% CI = 0.0 to 1), gait (MD = 0, 95% CI = 0.0 to 1), stand-to-sit (MD = 0, 95% CI = 0.0 to 1), and total score (MD = 2.0, 95% CI = 0.0 to 6) were not different between groups. Subacute participants presented significant better scores during turn activity (MD = 2.0, 95% CI 0.0 to 2.0). All kinematic variables were not different between participants.

CONCLUSIONS

Capacity to perform functional activities was not different within the first year post-stroke, suggesting that biomechanical strategies are developed within the first three months following stroke.

Increasing the Propulsive Demands of Walking to their Maximum Elucidates Functionally Limiting Impairments in Older Adult Gait

We elucidated functional limitations in older adult gait by increasing horizontal impeding forces and walking speed to their maximums compared to dynamometry and to data from their young counterparts. Specifically, we investigated which determinants of push-off intensity represent genuine functionally limiting impairments in older adult gait versus biomechanical changes that do not directly limit walking performance. We found that older adults walked at their preferred speed with hallmark deficits in push-off intensity. These subjects were fully capable of overcoming deficits in propulsive ground reaction force, trailing limb positive work, trailing leg and hip extension, and ankle power generation when the propulsive demands of walking were increased to maximum. Of the outcomes tested, age-related deficits in ankle moment emerged as the lone genuine functionally limiting impairment in older adults. Distinguishing genuine functional limitations from age-related differences masquerading as limitations represents a critical step toward the development and prescription of effective interventions.