Key result
In rat skinned cardiac muscle, decreasing sarcomere length below 2.2 microns reduced both force development and ATPase activity, with force falling more than ATPase activity at intermediate lengths.
Population
Rat skinned trabeculae (n=6)
Comparison
Variation of muscle length vs Different muscle lengths
Design
Preclinical
Authors
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Does not inform clinical practice; leaves open the role of restoring forces in human cardiac length-tension relations.
The decline of force production at short sarcomere lengths in cardiac muscle results partly from a fall in cross-bridge cycling and partly from an opposing restoring force.
Kentish et al. (1994) studied Rat skinned cardiac muscle (n=6). Muscle length variation vs. Different muscle lengths was evaluated on Myofibrillar force development and MgATPase activity. In rat skinned cardiac muscle, decreasing sarcomere length below 2.2 microns reduced both force development and ATPase activity, with force falling more than ATPase activity at intermediate lengths.
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