As muscle size increases, so does the resting metabolism. If two individuals have the same weight, but have different amounts of muscle mass, the one with the more muscle can ingest more calories without gaining weight. Loss of lean tissue is thought to be the main reason for the decrease in metabolism as people grow older. If people continue eating at the same rate as their activity decreases, body fat increases. Because muscle tissue is more dense than fatty tissue, people often become discouraged because they don t lose weight.
Endurance is the ability of a muscle to exert submaximal force repeatedly over time.
Muscular endurance depends on muscular strength and to a much lesser extent on cardiorespiratory endurance. Slow twitch or red fibers have a greater capacity for aerobic work. Fast twitch or white fibers have a greater capacity for anaerobic work. Amount of AA Overload principle - for strength to improve, the demands placed on the muscle must be increased systematically and progressively over time. Specificity of Training - for a muscle to increase in strength or endurance, the training program must be specific to obtain the desired effects.