Skeletal Muscle’s Involvement in Movement

Skeletal Muscle’s Involvement in Movement -...

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Unformatted text preview: Skeletal Muscle’s Involvement in Movement Involvement HES 303 Lenoir­Rhyne University Properties of Skeletal Muscle Properties Extensibility – ability to increase in length functionally and anatomically Elasticity – Ability to return to normal resting length following stretch or eccentric load Example: Flexibility Exercise leads to Increased ROM and muscle length Properties of Skeletal Muscle Properties Efficiency of these properties depends on stresses placed on the muscle as well as the process of adaptation. (SAID Principle) Example – Extensibility increases as a result of stretching exercises that are done thoroughly and consistently over time Example #2 – Plyometric Training increases speed and efficiency of elastic properties of trained muscle when done properly over time How does this prevent injury??? Stretch­shortening cycle efficiency Properties of Skeletal Muscle Properties Irritability – Muscle’s ability to respond to a stimulus Example) Muscles contain sensors that detect muscle length Ability to develop tension – Contractile ability of muscle What happens when there is not sufficient “irritability”? Golgi Tendon Organs Muscle Spindle Muscle Fibers Muscle What do you know about muscle fibers? Vary in length Line up according to tension developed Grow in both diameter and length from birth through adulthood Fiber diameter can be increased through resistance training (Hypertrophy) Types of Muscle Fibers Types 3 main types: Type I – Slow Twitch Oxidative Slow Contraction Slow Fatigue rate Smaller in width Adaptable Fast Contraction Type IIa – Fast Twitch Oxidative Glycolytic Type IIb – Fast Twitch Glycolytic Anaerobic Fast and most powerful contraction Easily fatigue Larger in width Organization of Skeletal Muscle Refer to Figure 11.4 on p. 256 Parallel – Fibers align parallel to longitudinal axis of muscle Pennate – Short fibers that attach to on or more tendons within muscle Example: Rectus Abdominus Unipennate – Tibialis Anterior Bipennate – Rectus Femoris Multipennate ­ Deltoid Function of Muscle Function Muscle “Actions” are based on change in length: Concentric Eccentric Example??? Example??? Example??? Isometric Roles of Muscles Roles Agonist – causes movement Antagonist – slows or stops movement Stabilizer – acts isometrically to stabilize joint(s) involved Neutralizer – Acts to eliminate unwanted action produced by agonist Example: Hammer Curl Synergy Synergy Assisted action by a muscle to the agonist muscle Example: Bench Press How so??? ...
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