1. Chapter Thirteen Understanding the Muscular System

2. Benefits of Muscular Fitness ä ä Reduce risk of muscle injury ä ä Increase capacity to perform daily tasks and activity by reducing fatigue ä ä Reduce bone and muscle loss as you age ä ä Improved physical appearance ä ä Reduce chance of health-related problems ä ä Aids in weight control

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

4. Muscle Basics MUSCLE – a band of fibers which shorten and lengthen to produce movement. TYPES OF MUSCLE 1. skeletal muscles – located around the joints and bones and allow us to move 2. cardiac muscles – the muscles of the heart 3. smooth muscles – found in arteries and internal organs, controls bodily functions (i.e. digestion) ä ä

5. CONNECTIVE TISSUE 1. Ligament– connects bone to bone 2. Tendon – connects muscles to bone 3. Cartilage – found between the bones, acts as a cushion

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

7. Muscle Fibers 1. Slow-twitch muscle fibers – move slowly but last long, good for endurance activities (i.e. long distance running or swimming) 2. Fast-twitch muscle fibers – move quickly but do not last long, good for quick burst activities (i.e. sprinting or shotput) 3. Intermediate fast-twitch muscle fibers – in between fast and slow, good for high intensity, moderate duration activities (i.e. middle distance running)