1. MUSCULAR STRENGTH AND ENDURANCE HEALTH-RELATED FITNESS COMPONENTS

2. OBJECTIVES ▪ Content Objective: Students will be able to differentiate between isokinetic, isometric, and isotonic exercises by placing example exercises into their correct column on a worksheet. ▪ Content Objective 2: Students will be able to identify differences between muscular strength and muscular endurance when given a statement on a worksheet.

3. DEFINITION REVIEW ▪ Muscular Strength: The ability of a muscle group to apply a maximal force against a resistance one time. ▪ Resistance = the amount of weight lifted ▪ Muscular Endurance: The ability to repeat muscle movement over a period of time.

4. MUSCULAR STRENGTH VS. MUSCULAR ENDURANCE Muscular StrengthMuscular Endurance 4-8 Repetitions Heavier Resistance Build Muscle Mass (“bulk-up”) Use Fast-Twitch Fibers One-Rep Max 10-20 Repetitions Lighter Resistance Get in shape (“toned”) Use slow-twitch fibers Prolonged use Build Strength Cause fatigue Necessary for daily activities

5. MUSCULAR FITNESS FACTS ▪ Physical Appearance and Weight ▪ Muscle is denser than fat ▪ One pound of muscle takes up less space than one pound of fat ▪ Toned muscles help prevent the build-up of fat cells in the abdomen ▪ Toned muscles allow you to have better posture and therefore look better ▪ Additional Benefits ▪ Help you perform physical activity better ▪ Help reduce fatigue ▪ Help minimize back pain ▪ Prevent muscle injuries

6. MUSCLE ATROPHY Definition: The wasting or loss of muscle tissue ▪ Occurs from: ▪ Lack of physical activity ▪ Not using the muscles enough ▪ Medical condition that limits movement ▪ Broken bones in casts ▪ Bedridden ▪ Astronauts away from gravity ▪ Most severe type of atrophy is from neurogenic atrophy ▪ Examples: Amyotrophic Lateral Sclerosis (ALS) ▪ Polio

7. SKELETAL MUSCLE REVIEW ▪ What color are slow twitch muscle fibers and why? ▪ Red because they require oxygen and therefore have a large amount of blood supply directed towards them ▪ They are slow to contract but can contract for long periods of time ▪ Best for aerobic or muscular endurance exercises because they do not fatigue easily. ▪ What color are fast twitch muscle fibers and why? ▪ White because they utilize the anaerobic pathway and therefore do not require the use of oxygen requiring a minimal amount of blood supply. ▪ They allow explosive muscular contraction and fatigue easily ▪ Best for strength and power (anaerobic activities) related activities such as sprinting ▪ We also have intermediate twitch muscle fibers which contain both slow and fast twitch characteristics.

8. THREE METHODS OF DEVELOPING MUSCULAR FITNESS 1.Isometric Exercises 2.Isotonic Exercises 3.Isokinetic Exercises

9. ISOMETRIC EXERCISE Definition: You contract (tighten) your muscles but do not change their length ▪ In an isometric exercise there is no movement of the body part ▪ Example of isometric exercise: ▪ Squeezing a tennis ball in your hand ▪ What other exercise examples can you think of? ▪ Strength improvement will occur from isometric exercises but only at the position the exercise is performed and not throughout the entire range of motion for that muscle. ▪ Disadvantage Isometric exercises are the least effective of the three in developing strength and endurance. It also may cause the persons blood pressure to raise. ▪ Benefit – They require no special equipment and can be done on a small space

10. ISOTONIC EXERCISES Definition: Exercises in which you lengthen or shorten the muscle through a full range of movement while lowering and raising a resistance. ▪ Resistance = Own body weight, barbell, dumbbell, medicine ball, kettle bell ▪ In isotonic exercises the muscle contracts to move the body part ▪ Example of Isotonic Exercises: Dumbbell Curl ▪ What other isotonic exercises can you think of? ▪ With isotonic exercises the amount of weight the muscle is able to lift varies throughout the range of motion ▪ Disadvantage: The amount of weight you can lift through the full range of motion may not overload the muscle at the strongest joint position ▪ Advantage: Excellent method of enhancing muscular fitness

11. ISOKINETIC EXERCISES Definition: A specially designed machine that mechanically allows you to overload a muscle with maximum resistance throughout the muscle’s entire range of movement at a constant speed. ▪ The isokinetic machine is set to move at a specific speed and the machine adjusts it’s resistance to constantly move at that speed ▪ Exercise Example: Dynamometer ▪ What other muscle exercise examples can you think of? ▪ Advantage: Maximum resistance is provided at the stronger angles, while less resistance is provided at the weaker angles. ▪ Disadvantage: There are few truly isokinetic weight-training machines in fitness centers that provide both speed and constant resistance.