Hip pull-off and ankle push-off in healthy and Parkinson's disease's gait
University of Southampton, School of Health Sciences,
An emerging theme in the analysis of the gait of people with Parkinson’s disease (PD) is that the kinetic features such as joint power generated during the events of ankle push-off and hip pull-off required for propulsion and progression of the lower limb is diminished inspite of PD medication. However, there is lack of sufficient evidence from the proponents of these PD gait deficiencies. Furthermore, it was thought in the present study that the cause of reduced joint power (if observed) could be attributed to their preferred slow walking speed Therefore, the research presented in this thesis investigated the pull and push-off events at usual walking speed (in healthy and people with PD) and at fast walking speed (in PD) to examine and substantiate what the other studies suggested.
The first part of the investigation into pull and push-off was to characterise and describe these gait events in healthy people whilst the second part was carried out on people affected with PD. A laboratory protocol/setup was designed for the first part of the study that was modified for use in the second part.
Fourteen healthy adults (mean age 63.6 ±7 years) participated in the first (laboratory based) study. Their gait was measured using a camera based motion analysis system (Coda mpx30) and a force platform that was situated on an 8m walkway. A gait laboratory test session was conducted per subject and the result of gait components of pull and push-off powers, ankle and hip joint angular excursion and corresponding gait velocity, stride length and cadence were recorded. Similar laboratory sessions with modification to the protocol/set up were also conducted (after an initial home clinical assessment and screening) for people with PD (n=11, mean age 66.4 ±5.07 years, disease duration 6±3.1 years, motor UPDRS score 24.3±9.98) walking at their usual and fast speeds during their on phase of PD medication.
The results showed that the gait of healthy subjects and subjects with PD was not significantly different from each other. Some PD subjects had greater pull-off and push-off powers than healthy subjects whilst a relationship between hip pull-off power and ankle plantarflexion suggests a compensatory strategy being used by PD subjects. PD subjects were able to significantly walk fast when asked to do so, with increments in the gait components. The results suggests that reduced pull and push-off powers are not applicable to all cases of PD and inspite of any diminished gait features their capacity to walk fast was still preserved.
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