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Updated: Jun 23, 2026
07:42
Live Cell Imaging during Mechanical Stretch
Published on: August 19, 2015
Does residual force enhancement increase with increasing stretch magnitudes?
Brandon Hisey1, Tim R Leonard1, Walter Herzog1
1Human Performance Lab., Faculty of Kinesiology, University of Calgary, 2500 University Drive N.W. Calgary, Alberta, Canada T2N 1N4.
Journal of Biomechanics
|May 16, 2009
Summary
Skeletal muscle force enhancement increases with stretch magnitude only on the descending limb of the force-length relationship, not unconditionally. This effect is linked to naturally occurring passive force within the muscle.
Area of Science:
- Biomechanics
- Skeletal Muscle Physiology
Background:
- Force enhancement in skeletal muscles is generally thought to increase with stretch magnitude.
- This property has not been extensively studied across supra-physiological stretches or varying muscle lengths.
Purpose of the Study:
- To investigate if force enhancement increases with stretch magnitude independent of muscle length.
- To determine if the accepted property holds true across a wider range of stretch magnitudes and muscle lengths.
Main Methods:
- Six cat soleus muscles were actively stretched across a range of magnitudes (3-24 mm).
- Stretches were performed at three distinct points on the force-length relationship.
- Residual and passive force enhancement were measured under varying stretch conditions.
Main Results:
- Force enhancement increased with stretch magnitude on the descending limb of the force-length relationship up to a plateau.
- Force enhancement did not increase with stretch magnitude on the ascending limb.
- Passive force enhancement was observed across all conditions and mirrored residual force enhancement behavior.
Conclusions:
- Force enhancement does not unconditionally increase with stretch magnitude.
- The relationship between increasing force enhancement and stretch magnitude is dependent on the presence of natural passive force within the muscle.
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