HSS 2111 Lecture Notes - Lecture 7: Hip, Mechanical Advantage, Muscle Contraction

• School: University of Ottawa
• Department: Health Sciences
• Course: HSS 2111
• Professor: Tien Nguyen

Document Summary

Muscle functions in movement - classified into agonist, synergist, antagonist. +active: internal force for movement & passive: external force causes movement (resistances of wind/water etc. , gravity) Isolated-single joint vs compound-multiple joint -most of the multiple joint movement in daily days. Types of muscle contraction: *both has force: isometric (static) contraction: Only gives postural position and allow static contraction used in standing, sitting, maintaining posture: isotonic (dynamic) contraction: Visible joint movement, muscles are shortening/lengthening with production of force includes: eccentric: lengthening concentric: shortening isometric: no movement-but supporting the load. Eccentric contraction resists all force that can provide most amount of the force. ***maximal amount of force shown on putting it downward (eccentric contraction) Concentric force is the weakest force produced even if it lifts the loads upper. Factors affecting force production based on contraction of eccentric, concentric, isometric. Motor unit recruitment, cross sectional area, fibre arrangement, muscle length. Less of energy involved in the eccentric, but allowing strongest resistance.