The relation between medio-lateral trunk movements and ankle power and work during the push off phase of gait

The relation between medio-lateral trunk movements and ankle power and work during the push off phase of gait

Vossen, Lisa (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Biomechanical Engineering)

Harlaar, Jaap (mentor)
Veeger, DirkJan (graduation committee)
Smit, Gerwin (graduation committee)

Delft University of Technology

Biomedical Engineering | BioMechatronics

2019-07-04

Joint kinetics measured during level walking demonstrates that the main source of energy occurs around the ankle joint, i.e. a large power burst during push off. This power burst can be divided into two mechanisms; pre-emptive push off and a push off to accelerate the leg into swing. This division is marked by the contralateral initial contact, i.e. the impactful start of weight transfer to that foot. This impact is the main energy absorbing event during gait that will be decreased by a pre-emptive push off. It is hypothesized that the medio-lateral position of the Center of Mass of the body controls the weight shift and thus the division of the ankle power into these two mechanisms. Since the trunk has a rather large mass compared to other body segments, the position of the Center of Mass of the trunk has a large influence on the total body Center of Mass. This led to the hypothesis of this study: the trunk controls the ankle power during gait. To verify this hypothesis eleven healthy subjects participated in this study, where gait kinematics and kinetics were obtained using motion capture and force plates. A lower- and upper-trunk was defined, based on a dedicated marker model. The tasks included normal walking as well as conditions to influence the medio-lateral trunk movements and the ankle power during gait. Differences and relations between the amount of ankle work during push off, the amount of ankle work within the two different mechanisms, maximum ankle power, and medio-lateral trunk angles for the different walking conditions were calculated. The amount of ankle work during push off is significantly – but modestly – related to the maximum amplitude of the lower trunk angle. This suggests that with an increasing trunk angle the amount of ankle work decreases. This relation was not found for the upper trunk angle or the Center of Mass of the entire upper body. The maximum ankle power during push off also has a small but significant relation with medio-lateral trunk movements. It can be concluded that with increasing medio-lateral trunk movements the amount of ankle power and work is slightly decreased. The division of the ankle work during push off into two parts is not significantly related to any increase in medio-lateral trunk movements. In the end, these results cannot point to a strong relation between ankle power or work and medio-lateral trunk movements. However, this is an exploratory study and to draw definite conclusions about this relation more extensive research is needed. It might also be interesting to investigate the possibilities of using increased medio-lateral trunk movements to relieve the ankle joint during walking.

gait
trunk
ankle power
push off

http://resolver.tudelft.nl/uuid:2514e1ce-b53a-48c6-856f-277d2bcf2326

Student theses

master thesis

© 2019 Lisa Vossen