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LEARNING OBJECTIVES

LEARNING OBJECTIVES

After reading this chapter, the learner should be able to demonstrate the following competencies and proficiencies concerning muscular strength:

  • A basic knowledge and understanding of muscular anatomy

  • A basic knowledge and understanding of how a muscle contracts

  • Compare and contrast the different muscle fiber types

  • Understand the terminology associated with strength programs

  • Describe, compare, and contrast the different types of muscle contraction

  • Describe factors that affect muscular strength, power, and endurance

  • Describe the overload principle

  • Compare and contrast open and closed kinetic chain exercises

  • A basic knowledge of exercise progression protocols

  • Describe the different types of resistive exercises

  • Describe and perform proprioceptive neuromuscular facilitation (PNF) exercises for the upper and lower extremity

  • Describe the variables in a resistive exercise program

  • Design a basic resistive exercise program

  • Understand the indications, precautions, and contraindication of implementing a resistive exercise program

INTRODUCTION

Muscular strength is a major component of designing every rehabilitation program. In addition to strength, power and endurance are essential components of every athletic training and conditioning program. Although rehabilitating an injury is different from preparing an uninjured athlete for competition, the same basic strengthening components and philosophies prevail across both applications. During the rehabilitation process, the focus is on preventing muscle atrophy and regaining muscular strength, power, and endurance to allow for safe and effective return to activity. During the strength and conditioning phase of an athlete's training, the focus is on improving performance through enhancement of strength, power, and endurance.1 The philosophy of "bigger, stronger, and faster" is often used when discussing strengthening and conditioning for competition. Although a discussion of strength training as a preventative tool will be addressed in this chapter, the focus of the chapter is squarely on the rehabilitation phase of strengthening.

ANATOMY AND PHYSIOLOGY OF SKELETAL MUSCLE

Muscle Anatomy

Muscles are made up of muscle fiber bundles called fascicles. Connective tissue separates each bundle and fasciculus. Perimysium separates the bundles and endomysium separates each fasciculus2–4 (Fig. 7-1). Muscles fibers have many nuclei and have a striated appearance when viewed under magnification. Each muscle fiber is composed of many sarcomeres, which are the contractile unit of the muscle. A sarcomere is made up of two types of myofibrils: thin and thick filaments. The thin filament, or actin filament, is a double strand of globular protein, which surrounds the thick filament. The thick filament, or myosin filament, is a single-strand protein, which has protruding heads at its ends2–4 (Fig. 7-2). The repeating arrangement of thick and thin myofilaments serves as the fundamental subunit of striated muscle contraction.2–4

Figure 7-2.

A sarcomere is made up of two types of myofibrils: thin filament (actin) and thick ...

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