Chapter 4 - Health & Lifestyles

Describe basic muscle physiology and the effects of strength training on muscles.
Define muscular strength and endurance, and their relationships to wellness.
Assess muscular strength and endurance.
Apply the FITT principle to create effective strength-training programs.
Discuss effects of supplements and drugs marketed to active individuals.
Explain safe performance of common strength-training exercises using various forms of resistance.

Muscles: Comprise over 40% of body mass.
Function: Muscles move the body and exert force.
- Muscle contraction moves bones by pulling on tendons.

Muscle Fiber: Single muscle cell, classified by:
- Strength
- Speed of contraction
- Energy source
Myofibrils: Protein structures within muscle fibers.
Nuclei: Multiple per muscle cell, containing DNA for protein production.
Satellite Cells: Activated by strength training to produce more nuclei.

Hypertrophy: Increase in muscle fiber size; stimulated by overload during strength training (initiates after 6-8 weeks).
Hyperplasia: Increase in number of muscle fibers (not significant in humans).
Atrophy: Decrease in muscle fiber size due to inactivity.
Types of Fibers:
- Slow-Twitch Fibers: Fatigue resistant, recruit for endurance activities, red in color.
- Fast-Twitch Fibers: Fatigue quickly, recruited for power or speed activities, white in color.
- Power: Ability to exert force rapidly.

Motor Unit: Comprises a motor nerve and associated muscle fibers.
- Axon: Conducts nerve impulses away from the nerve cell body.
- Myelin: Insulates the axon, speeding up neural conduction.
Muscle Learning: Improvement in motor unit recruitment through strength training.
- Maintains nerve connections and quickness.
- Helps in reducing bone loss and preventing falls (especially in older individuals).

Table 4.1: Physiological Changes and Benefits
- Increase in muscle mass and strength contributes to enhanced metabolism and longevity.
- Improvements in coordination and utilization of motor units.
- Strengthening of tendons and ligaments reduces injury risk.
- Enhancements in fuel storage and metabolic health may improve life span.

Strength training aids in preventing/manage cardiovascular disease and diabetes:
- Enhances glucose metabolism
- Improves oxygen consumption
- Affects blood pressure and cholesterol levels (in some individuals)
Stronger muscles reduce heart demand during daily activities.

Repetition Maximum (RM): Maximum weight that can be lifted for a specified number of repetitions.
- 1 RM: Maximum weight for one lift; 5-RM: Maximum weight for five lifts.
Repetitions: Count of exercises performed in one set.
Assessment Requirement: Push-ups and sit-ups mandatory; bench press optional.

Static vs. Dynamic Exercises:
- Isometric (Static): Muscle contraction without length change (e.g., planks).
- Isotonic (Dynamic): Muscle contraction with length change (e.g., biceps curls).
- Concentric: Muscle shortens while contracting.
- Eccentric: Muscle lengthens while contracting.
Dynamic Exercise Techniques:
- Constant Resistance: Same load throughout the motion (free weights).
- Variable Resistance: Changing load across the motion (some machines).
- Eccentric Loading: Load while lengthening muscle.
- Plyometrics: Rapid stretching and contraction of muscles.
- Speed Loading: Moving load quickly.
- Isokinetic: Provides variable resistance with a constant speed.

Static Exercises:
- Require no equipment; effective for fast strength gains and rehabilitation.
Dynamic Exercises:
- Utilize equipment; enhance strength and endurance across joint range.
Choice of exercise types depends on individual goals and resource availability.

Utilize proper techniques and equipment to avoid injury.
Familiarize with principles like R-I-C-E for injury management.
- Rhabdomyolysis: Serious condition causing muscle cell destruction.

Ergogenic Aids: Substances aimed at improving performance, but most are ineffective or dangerous.
Common performance aids include:
- Anabolic Steroids: Numerous serious side effects.
- Creatine: Often used to enhance performance and recovery.
- Caffeine: Increases alertness and energy.

Body Weight Exercises: Air squats, lunges, and push-ups among others.
Free Weight Exercises: Include a variety of movements such as bench press and biceps curls.
Weight Machine Exercises: Target specific muscle groups effectively.

Apply the FITT Principle:
- Frequency: At least twice a week with rest.
- Intensity: Sufficient weight to cause muscle fatigue.
- Time: Appropriate number of reps and sets (typically 1-3 sets, 8-12 reps).
- Type: Include exercises for all major muscle groups.
Ensure a warm-up before and cool-down post workout.