Improving Muscular Strength and Endurance © 2014 Pearson Education, Inc.

Learning Objectives Explain the benefits of developing muscular strength and endurance Describe how muscles contract Distinguish between the muscle fiber types Classify the types of muscular contractions Identify the changes that occur in response to strength training List the factors that determine muscle strength and endurance Outline the principles used in designing a strength and endurance program Distinguish between the types of training programs Design a program for improving strength and endurance © 2014 Pearson Education, Inc.

Strength Training in Daily Life Reduces joint and/or muscle injuries from exercise Reduces low back pain Delays and reduces age-related decreases in strength Helps prevent osteoporosis Increases resting energy expenditure (also called resting metabolic rate) © 2014 Pearson Education, Inc.

Muscle Structure and Function There are about 600 skeletal muscles in the body Primary function: provide force for movement and maintain posture and regulate temperature Muscles shorten or lengthen, causing bones and body to move Muscle structure: fibers, fascia, tendons Muscle function: motor nerves and muscle fibers are a motor unit © 2014 Pearson Education, Inc.

Structure of Skeletal Muscle © 2014 Pearson Education, Inc.

Major Muscles of the Body © 2014 Pearson Education, Inc.

A Motor Unit © 2014 Pearson Education, Inc.

Skeletal Muscle Exercise Classifications Isotonic (dynamic) Movement of a body part at a joint Most exercise and sports are isotonic Isometric (static) Uses muscle tension but involves no movement Good way to develop strength after injury Isokinetic Performed at a constant velocity Uses machines that provide resistance throughout the full range of motion © 2014 Pearson Education, Inc.

Muscle Action Classifications Isometric Action Actions are static and involve no movement Occurs during isometric exercise Concentric Action (positive work) Muscle shortens during movement against gravity or resistance Example: upward arm movement during a bicep curl Eccentric Action (negative work) Muscle lengthens during movement against gravity or resistance Example: downward arm movement during a bicep curl © 2014 Pearson Education, Inc.

Concentric and Eccentric Muscle Actions © 2014 Pearson Education, Inc.

Skeletal Muscle Fibers Types Slow-Twitch Fibers Contract slowly Generate little force but are resistant to fatigue Fast-Twitch Fibers Contract quickly Generate lots of force, but fatigue quickly Intermediate Fibers Serve as a combination of the other two types Contract rapidly, produce great force, and resist fatigue © 2014 Pearson Education, Inc.

Fiber Type Variations Most people have roughly equal numbers of all three types Elite endurance runners/marathoners have more slow-twitch fibers Elite speed runners/sprinters have more fast-twitch fibers There is a possible genetic link between a predominance of fast-twitch fibers and certain diseases, such as obesity and diabetes Research indicates fibers might be able to convert from one type to another through training Fiber recruitment - process involving more muscle fibers to increase muscle force © 2014 Pearson Education, Inc.

Recruitment of Muscle Fiber Type © 2014 Pearson Education, Inc.

Muscular Strength Amount of force muscle can generate, based on Size of the muscle (primary factor) The larger the muscle, the greater the force produced Number of muscle fibers recruited during a movement The more fibers that are stimulated, the greater the force generated © 2014 Pearson Education, Inc.

Muscle Fiber Recruitment and Muscular Force © 2014 Pearson Education, Inc.

Evaluating Muscular Strength and Endurance Muscular Strength Test One-repetition maximum (1 RM) test Measures maximum amount of weight that can be lifted one time (recommend for experienced lifters only) See lab 4.1 for evaluation worksheet Estimated 1 RM test, to reduce possible injury (recommended for beginner to intermediate lifters) See lab 4.2 for evaluation worksheet Muscular Endurance Tests Push-up test Sit-up or curl-up test See lab 4.4 for evaluation worksheet © 2014 Pearson Education, Inc.

Program Design Principles Progressive Resistance Exercise (PRE) Application of overload principle Progressively increase amount of resistance in the training Specificity of Training Development is specific to muscle group being exercised training intensity High-intensity training increases muscle size and strength Low-intensity training increases endurance © 2014 Pearson Education, Inc.

Improving Muscular Strength and Endurance © 2014 Pearson Education, Inc.

Strength Training Adaptations Physiological Changes Fiber recruitment patterns change Hypertrophy: increase in muscle size due to fiber size increase Not common: hyperplasia, the formation of new muscle fibers Rate of Improvement Depends on initial strength level Rapid strength gains in relatively untrained beginners More gradual gains in trained people with high levels of strength Gender Differences Little difference in initial responses to strength training After long-term training, men show greater gains due to higher testosterone levels Women DO NOT exhibit bulky muscles © 2014 Pearson Education, Inc.

Weight Training Program Design Safety Concerns Use spotters Don't drop weights Always warm up Breathe during exercises Use slow movements Start with light weights and work up gradually Types/Modes of Programs Isotonic–most common Isometric–least common, valsalva maneuver Isokinetic–not practical © 2014 Pearson Education, Inc.

Exercise Prescription Frequency Number of training days per week 2–3 days per week is optimal for strength gains Intensity Measured by the Repetition Maximum (RM) The number of consecutive repetitions performed without resting is a set Time (duration) Total number of sets performed Programs utilizing 3 sets result in greatest strength gains © 2014 Pearson Education, Inc.

Strength Gains: Based on Sets and Repetitions © 2014 Pearson Education, Inc.

Exercise Prescription Starter Phase 1–3 weeks Lighter weights, more repetitions Do only 1 set per exercise Frequency: twice a week Slow Progression Phase 4–20 weeks Heavier weights, fewer repetitions Increase sets per exercise to 2–3 Increase frequency to 2–3 times per week Maintenance Phase Starts around week 20 Requires a long-term commitment to maintain gains The effort needed to maintain gains is not as great as the initial effort As little as one workout a week can maintain strength © 2014 Pearson Education, Inc.

Guidelines and Precautions Prior to Beginning a Strength-Training Program © 2014 Pearson Education, Inc.

Staying Motivated Make time to train regularly Make training fun Find workout space or a facility you like Plan a program that's challenging but enjoyable Develop a realistic routine: don't make it so hard you'll get discouraged Work out with a friend or training partner Remember the benefits of strength training: better appearance, higher self-esteem, improved metabolism, and a feeling of accomplishment Complete the Steps for Behavior Change activity in the chapter if you feel reluctant to strength train © 2014 Pearson Education, Inc.

Sample Exercise Prescription for Weight Training: Beginner © 2014 Pearson Education, Inc.

Sample Exercise Prescription for Weight Training: Intermediate © 2014 Pearson Education, Inc.

Sample Exercise Prescription for Weight Training: Advanced © 2014 Pearson Education, Inc.

Exercise Videos: Safety Techniques Free Weights Safety Tips: Dumbbells Resistance Bands Safety Tips: Resistance Bands Stability Ball Safety Tips: Stability Ball PLAY PLAY PLAY © 2014 Pearson Education, Inc.

Summary Strength training can reduce back pain, decrease injuries, enhance bone health, and maintain age-related working capacity Strength is dependent on muscle size and fiber recruitment There are three major types of human skeletal muscles: slow-twitch, fast-twitch, and intermediate The amount of slow, fast, and intermediate muscles varies among individuals. There is a relationship between fiber type and success in some athletics. There may be a genetic connection between muscle fiber types and some diseases. Fiber recruitment is the process of involving more muscle fibers to produce increased force © 2014 Pearson Education, Inc.

Summary (cont.) Progressive resistance exercise (PRE) is the overload principle applied to resistance training Individualized programs can be specific for strength or endurance gains through mode, number of repetitions, and sets Isotonic (dynamic) exercises involve movement of a body part at a joint. Isometric (static) exercises use muscle tension but involve no movement. Isokinetic exercises are peformed at a constant velocity, often using machines. A strength training program has three phases: starter, slow progression, and maintenance © 2014 Pearson Education, Inc.