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The load/capacity ratio affects the sit-to-stand movement strategy
H H C M Savelberg1, A Fastenau, P J B Willems
1Department of Human Movement Science, Nutrition and Toxicology Research Institute, Faculty of Health, Medicine and Life Sciences, Universiteit Maastricht, Maastricht, The Netherlands. hans.savelberg@bw.unimaas.nl
Clinical Biomechanics (Bristol, Avon)
|June 19, 2007
Summary
Increasing external load significantly alters sit-to-stand strategy, affecting trunk flexion and movement time. This highlights the load/capacity ratio
Area of Science:
- Biomechanics
- Human Movement Science
- Kinesiology
Background:
- The load/capacity ratio impacts sit-to-stand (STS) performance, particularly in individuals with muscle weakness.
- This ratio can be experimentally manipulated by altering external load to study its isolated effects.
Purpose of the Study:
- To investigate how a changed load/capacity ratio affects STS performance.
- To examine the underlying changes in net joint moments during STS movements.
Main Methods:
- Ten healthy women performed STS under four load conditions (0-45% body mass added).
- Trunk flexion, temporal characteristics, joint moments (ankle, knee, hip), and muscle activation patterns were assessed.
Main Results:
- A 45% added load significantly increased trunk flexion and movement time.
- This strategy change correlated with increased hip extension moments and delayed knee extension moments.
Conclusions:
- Experimentally increased load/capacity ratio alters STS strategy.
- Interventions like strength training or weight reduction may improve STS performance by optimizing this ratio.
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