Chapter 5: Flexibility and Low-Back Health

Learning Objectives


. Identify the potential benefits of flexibility and stretching
. List the factors that affect a joint's flexibility.
. Describe the different types of stretching exercises and how they
affect muscles.
. Describe the intensity, duration, and frequency of stretching
exercises that will develop the most flexibility with the lowest risk
of injury.
. List safe stretching techniques for major joints.
. Explain how low-back pain can be prevented and managed.


This chapter describes the factors that affect flexibility and the benefits
of maintaining good flexibility. It provides guidelines for putting
together a successful stretching program to maintain optimal health.

Flexibility is the ability of a joint to move through its normal,
full range of motion.

A. ______________ is highly adaptable and can be increased through
regular stretching exercises.

B. __________ flexibility is the ability to hold an extended position at
one end or point in a joint's range of motion. It depends on your
ability to tolerate stretched muscles, the structure of the joint and
the tightness of muscles, tendons, and ligaments.

C. __________flexibility is the ability to move a joint through its range
of motion with little resistance. It depends on static flexibility,
but it also involves strength, coordination, and resistance to

I. What Determines Flexibility?

Flexibility is affected by a joint's structure, muscle elasticity and
length, and nervous system regulation.

A. Joint Structure

1. Joints have various structures:

a. _____________, such as those in your fingers and knees, allow
only limited forward and backward movement; they lock when fully

b. _____________ joints, like the hip, enable movement in many
different directions and have a greater range of motion.

c. Major joints are surrounded by ____________________, semielastic
structures containing _____________ fluid that give joints
strength and stability but limit movement.

2. _____________ plays a role in joint structure and flexibility.

3. Gender may also play a role. Some studies have found that women
have greater flexibility in certain joints.

B. Muscle Elasticity and Length

1. Two principal types of connective tissue are:

a. ___________, _________fibers that provide structure and support.

b. ___________, __________fibers that are elastic and flexible.

2. Titin also has elastic properties and contributes to flexibility

3. When a muscle is stretched, wavelike elastin fibers straighten.
This temporary lengthening is called ____________elongation. When
stretched over a longer period of time, the effect becomes
___________ elongation. Without regular stretching, the process

4. Flexibility is improved best if muscles are stretched when they
are warm (following exercise or the application of heat) and the
stretch is applied gradually and conservatively.

C. Nervous System Regulation

1. Nerves that send information about the muscle and skeletal
systems to the nervous system are _________________. When these
nerves detect any change in the position or force of muscles and
joints, they send signals to the spine and brain which send signals
back to coordinate muscle action in ways that protect muscles and
tendons from injury.

a. They control the speed, strength, and coordination of muscle

b. When a muscle is stretched, proprioceptors detect the amount and
rate of the change in muscle length.

c. Small movements that only slightly stimulate these receptors
cause small reflex actions.

d. Rapid, powerful, and sudden changes in muscle length strong
stimulate the receptors and can cause large and powerful reflex
muscle contractions.

e. The stretching technique called proprioceptive
neuromuscular facilitation (PNF) takes advantage of the nerve
activity to improve flexibility.

II. Benefits of Flexibility

Good flexibility can help prevent injuries and improve performance in
all physical activities.

A. Joint Health
Good flexibility is essential to joint health; joints surrounded by
tight muscles, tendons, and ligaments are subject to deterioration and
injury. Improved flexibility also increases your quality of life as
you get older, making it easier to perform everyday movements and

B. Prevention of Low-Back Pain and Injuries

1. Strength and flexibility in the back, pelvis, and thighs may
help prevent back pain.

2. People with either high or low flexibility seem to have an
increased risk of injury.

3. Stretching is recommended for older adults or people involved
with high-power sports.

4. Stretching before a high-intensity activity may