This research project investigated locomotor and postural strategies to adapt to uphill and downhill treadmill walking in healthy and spinal cord injured (SCI) subjects. In the first experiment, subjects from both groups walked uphill at three different inclinations (5, 10 and 15º) while holding on to the handrails on the treadmill. The goal of this first experiment was to characterize changes in lower limb movements and muscle activity patterns required for up-slope walking. The results showed that the key mechanism when adapting to uphill walking in healthy subjects was to lift up the swinging limb by performing a simultaneous increase in hip and knee flexion of that limb. An increase in ankle dorsiflexion was also required to place the foot properly on the inclined surface. Modifications in lower limb movements were accompanied by progressive increases in the peak amplitude of electromyographic activity of lower limb muscles as the treadmill grade went steeper. The most important increase was observed in the plantarflexor muscles during push off. This increase in muscle activity was necessary to propel the body forward and upward and counteract the resistance due to gravity in uphill conditions. In SCI subjects, a similar trend of adaptation was found only at the hip during uphill walking. Furthermore, the majority of lower limb muscles, including ankle plantarflexors, showed very limited adaptation during uphill walking. The limited changes observed in lower limb movements and muscle activity suggest that SCI subjects have to used different strategies than healthy subjects to adapt to uphill walking. These strategies could involve movements from the trunk and pelvis to compensate for lower limb deficits. / The second experiment specifically focused on the role of the trunk and pelvis in the strategies of adaptation to uphill and downhill treadmill walking in healthy and SCI subjects. Results from healthy subjects showed that walking on an inclined surface required modifications in trunk and pelvic vertical alignment in the sagittal plane. Uphill walking induced a progressive forward inclination of both trunk and pelvis whereas the opposite trend was found in downhill conditions. These modifications in trunk and pelvic alignment are necessary to counteract the effects of gravity on forward momentum at different slope conditions. In contrast to healthy subjects, SCI subjects with minor deficits in lower limb kinematic patterns showed a greater forward inclination of both trunk and pelvis during level and inclined walking, especially in downhill conditions where both segments were maintained at similar inclination as in level gait. SCI subjects with major deficits revealed analogous (but more pronounced) feature in trunk and pelvic orientation during walking. The whole group of subjects with SCI seemed to adopt this anterior posture to benefit from greater stability during level and inclined walking. Results from frontal and transverse plane motions revealed that compensatory movements from trunk and pelvis were performed only by subjects with SCI showing severe mobility dysfunctions. These compensatory movements were maintained similar across treadmill grades. Results from subjects with SCI and healthy subjects did not show any significant changes in trunk and pelvic total angular excursions in the three planes of motion when comparing level and inclined walking. This absence of changes suggests that lower limbs are mainly responsible for generating or absorbing more energy during uphill and downhill walking in these two groups of subjects.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.37762 |
| Date | January 2001 |
| Creators | Leroux, Alain. |
| Contributors | Barbeau, Hugues (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (School of Physical and Occupational Therapy.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001802369, proquestno: NQ70078, Theses scanned by UMI/ProQuest. |
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