Understanding the Muscular System Chapter Thirteen Understanding the Muscular System

The relationship between muscular strength and muscular endurance. Muscular Fitness Muscular Fitness The relationship between muscular strength and muscular endurance. Muscular Strength Amount of force that can be exerted by a single contraction of the muscle. Muscular Endurance Ability of a muscle group to continue muscle movement over a length of time.

Benefits of Muscular Fitness Reduce risk of muscle injury Increase capacity to perform daily tasks and activity by reducing fatigue Reduce bone and muscle loss as you age

Inadequate Muscular Fitness Low back pain Abnormal movement due to muscular imbalance Poor posture due to muscular weakness Inability to function effectively on a daily basis Muscular injuries

Muscle Basics Ligament Tendon Cartilage

The Muscle Fiber Slow-Twitch Muscle Fibers - needed for endurance-type activities such as distance running and cross country skiing Fast-Twitch Muscle Fibers - needed for fast, short burst activities requiring speed or power such as sprinting and shot putting Intermediate Fast-Twitch Muscle Fibers - Used in activities of high intensity and moderate duration

Muscle Growth Hypertrophy - the enlargement of the diameter of the muscle fiber Atrophy - a condition in which the muscle fibers become smaller in diameter due to lack of use Muscles do not turn into fat if you stop training!

Muscle Contractions Concentric contraction - shortening Pull ups, curl ups, and lifting weights Eccentric contraction - lengthening Lowering your body during a chin up Static contraction Placing one hand against another and pushing hard

Effects of Exercise The size of the muscle temporarily increases as the blood flow to it increases The body temperature rises due to the increased activity in the muscle tissue The increased temperature causes the muscles to become more flexible, able to contract more easily and at a faster rate

Understanding the Muscular System Muscular strength and muscular endurance are both integral components of health related fitness. One of the most important benefits of obtaining muscular fitness is improved physical appearance: • develop better posture • look firmer and trimmer • feel better Return to Chapter Menu