Name  Section  Date 
LAB 5.3: Assessing Muscular Endurance for Low-Back Health

The three tests in this lab evaluate the muscular endurance of major spine stablizing muscles.

Side Bridge Endurance Test  (Watch the QuickTime video)

Equipment
  1. Stopwatch or clock with a second hand
  2. Exercise mat
  3. Partner

Preparation
Warm up your muscles with some low-intensity activity such as walking or easy jogging. Practice assuming the side bridge position described below.

Instructions
  1. Lie on the mat on your side with your legs extended. Place your top foot in front of your lower foot for support. Lift your hips off the mat so that you are supporting yourself on one elbow and your feet (see photo). Your body should maintain a straight line. Breathe normally; don't hold your breath.
  2. Hold the position as long as possible. Your partner should keep track of the time and make sure that you maintain the correct position. Your final score is the total time you are able to hold the side bridge with correct form—from the time you lift your hips until your hips return to the mat.
  3. Rest for 5 minutes and then repeat the test on the other side. Record your times.

 
Right side bridge time: sec
Left side bridge time: sec

Trunk Flexors Endurance Test  (Watch the QuickTime video)

Equipment
  1. Stopwatch or clock with a second hand
  2. Exercise mat or padded exercise table
  3. Two helpers
  4. Jig angled at 60° from the floor or padded bench (optional)

Preparation
Warm up with some low-intensity activity such as walking or easy jogging.

Instructions

  1. To start, assume a sit-up posture with your back supported at an angle of 60° from the floor; support can be provided by a jig, a padded bench, or a spotter (see photos). Your knees and hips should both be flexed at 90°, and your arms should be folded across your chest with your hands placed on the opposite shoulders. Your toes should be secured under a toe strap or held by a partner.
  2. Your goal is to hold the starting position (isometric contraction) as long as possible after the support is pulled away. To begin the test, a helper should pull the jig or other support back about 10 cm (4 inches). A helper should keep track of the time; if a spotter is acting as your support, she or he should be ready to support your weight as soon as your torso begins to move back. Your final score is the total time you are able to hold the contraction—from the time the support is removed until any part of your back touches the support. Remember to breathe normally throughout the test.
  3. Record your time here and on the chart at the end of the lab.

Trunk flexors endurance time: sec


Back Entensors Endurance Test  (Watch the QuickTime video)

Equipment

  1. Stopwatch or clock with a second hand
  2. Extension bench with padded ankle support or any padded bench
  3. Partner

Preparation
Warm up with some low-intensity activity such as walking or easy jogging.

Instructions

  1. Lie face down on the test bench with the upper body extending out over the end of the bench and the pelvis, hips, and kneeds flat on the bench. Your arms should be folded across your chest with your hands placed on the opposite shoulders. Your feet should be secured under a padded strap or help by a partner.
  2. Your goal is to hold your upper body in a straight horizontal line with your lower body as long as possible. Keep your neck straight, and neutral; don't raise your head and don't arch your back. Breathe normally. Your partner should keep track of the time and watch your form. Your final score is the total time you are able to hold the horizontal position—from the time you assume the position until your upper body drops from the horizontal position.
  3. Record your time here and on the chart below.

Back extensors endurance time: sec

Rating Your Test Results for Muscular Endurance for Low-Back Health
The table below shows mean endurance times for healthy young college students with a mean age of 21 years. Compare your scores with the means shown in the table. (If you are older or have suffered from low-back pain in the past, these ratings are less accurate; however, your time scores can be used as a point of comparison.)

  Mean Endurance Times (sec)
  Right Side Bridge Left Side Bridge Trunk flexors Back extensors
Men 95 99 136 161
Women 75 78 134 185

SOURCE: McGill, S. M. 2002. Low Back Disorders: Evidence Based Prevention and Rehabilitation. Champaigne, Ill.: Human Kinetics.


Right side bridge: Rating (above mean, at mean, below mean):
Left side bridge: Rating (above mean, at mean, below mean):
Trunk flexors: Rating (above mean, at mean, below mean):
Back extensors: Rating (above mean, at mean, below mean):

Using Your Results

How did you score? Are you at all surprised by your scores for the low-back tests? Are you satisfied with your current ratings?

If you're not satisfied, set a realistic goal for improvement. The norms in this lab are based on healthy young adults, so a score above the mean may or may not be realistic for you. Instead, you may want to set a specific goal based on time rather than rating; for example, set a goal of improving your time by 10%. Imbalances in muscular endurance have been linked with back problems, so if your rating is significantly lower for one of the three tests, you should focus particular attention on that area of the body.

Goal:

What should you do next? Enter the results of this lab in the Preprogram Assessment column in Appendix D. If you've set a goal for improvement, begin a program of low-back exercises such as that suggested in this chapter. After several weeks of your program, complete this lab again and enter the results in the Postprogram Assessment column of Appendix D. How do the results compare?