Chapter 12 Flexibility

Key Concepts

• ballistic stretching• contract-relax

(CR)• contract-relax

with agonist-contraction (CRAC)

• dynamic flexibility

• proprioceptive neuromuscular facilitation (PNF)

• static flexibility• static stretching• stretch reflex

Review Questions

Why is flexibility important?

• For health: – contributes to efficient movement in

walking and running– prevents or relieves aches and pains as

one ages

• For athletics:– need for flexibility in specific joints,

which varies with athletic activity (e.g., hurdler needs hip flexion and extension flexibility)

What sets the limits of flexibility?

• Bony structure (e.g., knee or elbow)• Soft tissues, including muscle and

connective tissue, and skin (e.g., ankle or hip)

Review the physical properties important to stretching.

• A low-force stretching method requires more or less time to produce a given elongation than does a higher-force method?– more

• The proportion of elongation that remains after stretching is greater or lesser with low-force, long-duration stretching than with high-force stretching?– greater

• The amount of structural weakening produced by a given amount of tissue elongation varies how with temperature?– inversely

Should stretching be used as part of a warm-up routine?

No. You should warm-up with mild exerciseprior to stretching to avoid injury.

Which is more important to an athlete: static or dynamic flexibility?

Dynamic flexibility, which is the ability tomove the limb quickly with little resistance.

• A muscle that is stretched with a jerky motion responds how?– A contraction (stretch reflex) whose amount

and rate vary directly with the amount and rate of the movement that causes the stretch

• A muscle that is stretched with a steady, static stretch invokes what? – Inverse myotatic reflex that brings about the

inhibition not only of the muscle whose tendon organ was stretched but of the entire functional group of muscles involved

What three advantages does static stretching have over ballistic stretching?

• There is less danger of exceeding the extensibility limits of the tissues involved.

• Energy requirements are lower.

• Static stretching does not cause muscular soreness.

How long should a stretch be held?

For 30-60 seconds.

Does the following figure illustrate static or ballistic stretches?

Ballistic

Does the following figure illustrate static or ballistic stretches?

Static

What are some general guidelines for designing static or PNF stretching programs?

• Select one or more stretching exercise(s) for each muscle group to be trained

• Slowly increase the force of the stretch to a point of mild to moderate discomfort

• Hold this position for 30-60 seconds• If used, proceed with PNF methods• Repeat the stretch two to three times• Total stretching program normally takes

15 to 30 minutes

What five factors affect flexibility? How?

• Activity– Active people tend to be more flexible.

• Weight training– It is generally believed that proper weight

training has no negative effects on, and may improve, flexibility.

• Gender– Women tend to be more flexible than men.

• Age– In general, we become less flexible with age.

• Temperature– Dynamic flexibility increases with warmth and

decreases with cooling.

Useful Websites

Types of Stretching

www.bath.ac.uk/~masrjb/Stretch/stretching_4.html

PNF Stretchingwww.sport-fitness-advisor.com/pnfstretching.html

Flexibility and Stretching Web Linkshttp://sportsmedicine.about.com/cs/flexibility/

Flexibility Basicswww.fun-and-fitness.com/info-zone/flexibility.html

Selected Images

Figure 12.1 Examples of ballistic stretching methods.

1. Trunk lifter.a. Hands raised behind neck.b. Raise head and chest vigorously.c. Partner holds feet.

3. Trunk bender.a. Legs apart and straight.b. Hands behind neck.c. Bend trunk downward in a bouncing fashion.d. Keep back straight.

5. Trunk rotator.a. Arms extended laterally.b. Twist to left and then to right.

7. Single leg raiser.a. Front leaning rest position.b. Keep feet in extended position.c. Raise one leg at time. Alternately.

2. Leg lifter.a. Arms down at side.b. Raise both legs off floor and return vigorously.

4. Upper back stretcher.a. Legs crossed, sitting position.b. Try to touch head to floor.c. Use vigorous bouncing motion.

6. Gastocnemius stretcher.a. Stand on raised surface on balls of feet.b. Lower weight and return rapidly.c. Use partner to balance if necessary.

8. Arm and leg lifter.a. Supine position, arms and legs extended.b. Whip arms and legs up and down alternately. c. Right arm and left leg come up simultaneously and vice versa.

Figure 12.2 Examples of static stretching methods. 1. Upper trunk

stretcher.a. Keep pelvis on floor.b. Extend arms.

3. Lower back stretcher.a. Legs extended-toes pointed.b. Grasp outer borders of feet and pull head downward.

5. Trunk twister.a. Turn at trunk.b. Turn head in direction of trunk.

7. Toe pointer.a. Sit on feet, toes and ankles stretched backward.b. Raise knees from floor slightly.c. Balance weight with both hands on floor just behind hips.

2. Lower trunk stretcher.a. Grasp ankles from behind and pull.b. Hold head up.

4. Upper back stretcher.a. Raise legs up and over head.b. Rest extended toes on floor.c. Leave hands and arms flat on floor.

6. Gastrocnemius stretcher.a. Feet 3 to 4 feet from wall.b. Keep body straight.c. Keep feet parallel and heels on floor.

8. Shoulder stretcher.a. Bring right hand to upper back from above.b. Bring left hand to upper back from below and hook fingers of the two hands.c. Repeat on other side.

Figure 12.3 Example of contract-relax (CR) proprioceptive neuromuscular facilitation (PNF) stretching method.

1. Lie on your back and place towel around the bottom of one foot.

2. Fully straighten leg, lift until you feel moderate resistance.

3. Contract hamstring muscle for 5-10 seconds.

4. Pull on the towel to further stretch the hamstring muscle.