STUDY DESIGN: Prospective, single-group, repeated-measures design. OBJECTIVE: To analyze the longissimus thoracis and lumbar multifidi muscle activity with surface electromyography (EMG) during exercises used in back rehabilitation programs. BACKGROUND: Physical therapists use a variety of exercises when rehabilitating patients with low back pain (LBP). EMG analysis of exercises can provide a measure of muscle activation so a clinician can have a better idea about the effect the exercise may have on the muscle for stabilization, endurance, or strength training. METHODS AND MEASURES: Surface EMG analysis of the muscle activity of the longissimus thoracis and lumbar multifidi was carried out bilaterally on 3 different experimental groups while performing a variety of exercises commonly used in low back rehabilitation programs. Groups 1 and 2 each had 30 subjects and group 2 had 29 subjects, ranging in age from 21 to 35 years. All EMG data during exercises were normalized to percent of the maximum voluntary isometric contraction (MVIC). RESULTS: The lumbar multifidus and longissimus thoracis muscles were most active, with EMG amplitudes of greater than 92% ± 12% MVIC during prone lumbar extension to end range with resistance applied. Prone lumbar extension to neutral, resisted lumbar extension while sitting, and prone extension with the upper and lower extremities lifted (Superman exercise) produced EMG amplitudes ranging from a mean ± SD of 77% ± 13% to 82% ± 12% MVIC. Exercises that produced EMG amplitudes of less than 50% MVIC were bridging exercises, the side-bridge exercise, and upper and lower extremity raises in either the prone or quadruped positions. CONCLUSION: The findings from this study may be helpful for physical therapists in selecting exercises when progressing patients with LBP from low-intensity exercises to those that require more muscle activity. 

J Orthop Sports Phys Ther. 2008;38(12):736-745, published online 22 August 2008. doi:10.2519/jospt.2008.2865

KEY WORDS: endurance, lumbar spine, stabilization, strength

STUDY DESIGN: Prospective, single-group, repeated-measures design. OBJECTIVE: To identify exercises that could be used for strength development and the exercises that would be more appropriate for endurance or stabilization training. BACKGROUND: The exercises analyzed are often used in rehabilitation programs for the spine, hip, and knee. They are active exercises using body weight for resistance; thus a clinician is unable to determine the amount of resistance being applied to a muscle group. Electromyographic (EMG) analysis can provide a measure of muscle activation so that the clinician can have a better idea about the effect the exercise may have on the muscle for strength, endurance, or stabilization. METHODS AND MEASURES: Surface EMG analysis was carried out in 19 males and 11 females while performing the following 9 exercises: active hip abduction, bridge, unilateral-bridge, side-bridge, prone-bridge on the elbows and toes, quadruped arm/lower extremity lift, lateral step-up, standing lunge, and using the Dynamic Edge. The rectus abdominis, external oblique abdominis, longissimus thoracis, lumbar multifidus, gluteus maximus, gluteus medius, vastus medialis obliquus, and hamstring muscles were studied. RESULTS: In healthy subjects, the lateral step-up and the lunge exercises produced EMG levels greater than 45% maximum voluntary isometric contraction (MVIC) in the vastus medialis obliquus, which suggests that they may be beneficial for strengthening that muscle. The side-bridge exercise could be used for strengthening the gluteus medius and the external oblique abdominis muscles, and the quadruped arm/lower extremity lift exercise may help strengthen the gluteus maximus muscle. All the other exercises produced EMG levels less than 45% MVIC, so they may be more beneficial for training endurance or stabilization in healthy subjects. CONCLUSION: Our results suggest these exercises could be used for a core rehabilitation or performance enhancement program. Depending on the individual needs of a patient or athlete, some of the exercises may be more beneficial than others for achieving strength.

J Orthop Sports Phys Ther 2007;37(12):754-762, published online 29 August 2007. doi:10.2519/jospt.2007.2471

KEY WORDS:  endurance, lower extremity, spine, stabilization, strength

J Orthop Sports Phys Ther. 2003;33(5):247-258.

Key Words: scapula, shoulder, strength, upper extremity

Study Design: Prospective single-group repeated-measures design. Objective: To use electromyographic (EMG) analysis during muscle testing to determine if there is a difference in function of the upper and lower parts of the serratus anterior (SA) muscle. Background: The SA muscle is a very important scapular protractor and upward rotator. Authors have anatomically described the muscle as being divided into 2 or 3 parts, and have suggested that the upper part is more suited for protraction and the lower part for upward rotation of the scapula. Methods and Measures: Surface electrodes recorded EMG activity of the upper and lower parts of the SA muscle during 9 different muscle tests in 29 healthy subjects. Results: Three muscle tests demonstrated significantly greater (P<.05) EMG activity in the lower part of the SA as compared to the upper part. There was no significant difference in the EMG activity of the upper and lower parts of the SA when the other 6 muscle tests were analyzed. Conclusion: When upward rotation was the primary position of the scapula during the muscle tests, the lower part of the SA was activated to a greater degree than the upper part. Muscle tests with maximum scapular protraction with varying degrees of upward rotation produced EMG activity with no significant difference when comparing the upper and lower parts of the SA. This information may be helpful for clinicians when muscle testing and developing exercise programs for the SA muscle.

J Orthop Sport Phys Ther. 2004; 34(5):235-243. doi:10.2519/jospt.2004.1345

Key Words: scapula, shoulder, strength, upper extremity