1. Understanding the Muscular System
Chapter Thirteen
Understanding the Muscular System

2. 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.

3. 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

4. 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

5. Muscle Basics
Ligament
Tendon
Cartilage

6. 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

7. 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!

8. 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

9. 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

10. 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
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