Table of Contents
- Introduction
- Review of Related Literature
- Force-Length Relationship of the Muscle
- Energy for Muscle Contraction
- Summary and Conclusion
- References
Introduction
Contraction refers to the active process of generating a force in a muscle. The force exerted by a contracting muscle on an object is referred to as the muscle tension, whereas the force exerted on a muscle by the weight of an object is referred to as the load. Muscle tension and load are thus opposing forces, and to lift a load, the muscle tension must exceed the load. When a muscle is allowed to shorten and lift a load, the contraction is said to be isotonic (constant tension) since the load lifted remains constant throughout the period of shortening. From isotonic measurements one obtains the velocity of shortening with various loads, a property of the contractile apparatus of the muscle.
When shortening is prevented, the development of tension occurs at constant muscle length and the contraction is termed isometric (constant length). Isometric measurements indicate the degree of tension developed in elastic elements of a muscle at a fixed length. You will determine the properties of isotonic and isometric muscle contractions.
Because of the tendon compliance, muscles will experience non-isometric contractions during static tasks (i.e., fixed joint angles) if the load is time varying. It was derived that the velocity of any muscle in static tasks is dependent on two parameters: the ratio of its tendon slack length to optimum muscle length and the strain rate. The contracting velocities, though low for many muscles as compared to the maximum shortening velocities they can generate, may result in significant modification in their force generation due to the steep slope of the Hill-curve near the point of zero-velocity.........
