Effects of Hip flexion/extension coupling ratio on gait
Date Issued
2010
Date
2010
Author(s)
Chen, Ting-Wei
Abstract
RGO (reciprocating gait orthoses) were designed for paraplegic patients, the equipments could help them get up and gain physiological benefits as well. However, the orthoses were not well adopted because of the high energy cost and the slow walking speed, which led to a high abandon rate. Instead, patients would rather use wheelchair to go around. This designs of the old type reciprocating gait orthoses limited hip joints flexion and extension in 1:1 coupling ratio. In past studies, the researchers proved that using higher coupling ratio could decrease energy consumption and increase walking speed. Although there were a lot of new designs that could adjust coupling ratio, there was no related literature to prove the appropriate coupling ratio of the orthotic hip joint. And we wonder know if the higher coupling ratio could improve the gait efficiency or not.
The purpose of this study is to demonstrate the relationship between coupling ratio and different walking conditions. We anticipated the results might be the guideline to improve hip joint mechanism design in the future.
In our study, we used Optotrak to collect movement data and AMTI force plate data from 9 young health people to analyze their kinetic performance. We arrange different walking and joint conditions: slow to fast walking conditions and free to locked knee and ankle joint conditions. In the same time, we used the collective gait data to construct a biomechanical model to prove the mechanical role of the coupling ratio in normal gait.
There were three statistically significant differences when we compared the coupling ratio under different conditions. The coupling ratio in joint-locked condition were higher than joint-free condition under three speed conditions (Slow: p=0.009, self-select: p=0.003, fast: p=0.003). And we observed that the coupling ratio decreased while the walking speed got faster, but there is no statistical significance. In the results of model simulation, the bilateral hip joint coupling ratios were higher.
In conclusion, we found that normal people could adjust the coupling ratio higher than one in both joint-constrained conditions under three walking speed conditions in reciprocating period. And the modeling result shows that people might need higher coupling ratio for the energy-saving. So, for orthotic design in the future, the designed coupling ratio of orthosis in reciprocating period should be higher than one to achieve the smoothness of swing and energy-saving
Subjects
reciprocating gait orthoses
reciprocating period
hip joint
coupling ratio
modeling
SDGs
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