An Electromyographic Analysis of Commercial and Common Abdominal Exercises: Implications for Rehabilitation and Training

Abstract

Study Design: A repeated-measures, counterbalanced design. Objectives: To test the effectiveness of 7 commercial abdominal machines (Ab Slide, Ab Twister, Ab Rocker, Ab Roller, Ab Doer, Torso Track, SAM) and 2 common abdominal exercises (crunch, bent-knee sit-up) on activating abdominal and extraneous (nonabdominal) musculature. Background: Numerous abdominal machine exercises are believed to be effective in activating abdominal musculature and minimizing low back stress, but there are minimal data to substantiate these claims. Many of these exercises also activate nonabdominal musculature, which may or may not be beneficial. Methods and Measures: A convenience sample of 14 subjects performed 5 repetitions for each exercise. Electromyographic (EMG) data were recorded for upper and lower rectus abdominis, external and internal oblique, pectoralis major, triceps brachii, latissimus dorsi, lumbar paraspinals, and rectus femoris, and then normalized by maximum muscle contractions. Results: Upper and lower rectus abdominis EMG activities were greatest for the Ab Slide, Torso Track, crunch, and Ab Roller, while external and internal oblique EMG activities were greatest for the Ab Slide, Torso Track, crunch, and bent-knee sit-up. Pectoralis major, triceps brachii, and latissimus dorsi EMG activities were greatest for the Ab Slide and Torso Track. Lumbar paraspinal EMG activities were greatest for the Ab Doer, while rectus femoris EMG activities were greatest for the bent-knee sit-up, SAM, Ab Twister, Ab Rocker, and Ab Doer. Therapy, 6000 J Street, Sacramento, Conclusions: The Ab Slide and Torso Track were the most effective exercises in activating abdominal and upper extremity muscles while minimizing low back and rectus femoris (hip flexion) activity. The Ab Doer, Ab Twister, Ab Rocker, SAM, and bent-knee sit-up may be problematic for individuals with low back pathologies due to relatively high rectus femoris activity. J Orthop Sports Phys Ther 2006;36:45-57.

The Relationship between Muscle Activity and Muscle Grade of the Trunk Flexors Using Manual Muscle Testing with Electromyography

“…However, recent studies 17,20,[23][24][25] examining the muscle activity of the upper and lower rectus abdominal muscles during these motor tasks have reported that there is no difference between the muscle activity of the upper and lower RA and our results support these findings. Clark 17) suggested that the anatomical discovery that some RA fibers extend beyond the tendinous inscription might explain why there was no difference between upper and lower RA activity in the CU and DLL exercise tasks.…”

“…This disagreement may result from differences in the maneuvering and displacement of the recording electrodes used in each study. The %MVC of the upper and lower RA obtained during Normal in the CU test corresponded with results from previous studies that examined this task as a rehabilitation training 24,25) . Although we could not fully compare the DLL test, our data during Normal were similar to the data of Lehman and McGill 24) .…”

Gender Differences in the Curl-up and the Double-leg-lower Tests

“…Although muscle activities in each muscle grade in the CU test were signifi cantly larger than those in the DLL test, there was no difference between the two tests in the state (i.e., activity ratio) of the muscle activity. Recent studies have reported that there was no difference between the muscle activities of the URA and the LRA 2,3,23,29) , and the present study also failed to fi nd any difference in URA and LRA activity ratios between the tests performed by young subjects. Clark et al could not explain any difference in muscle activity between the RA muscle sites due to several RA fibers extending beyond the tendinous inscription 23) .…”

“…g . r e c t u s a b d o m i n a l m u s c l e , R A ) , i s recommended for the prevention and treatment of LBP 2,3) .…”

The effect of chronic low back pain on tactile suppression during back movements

“…It has to be noted that tactile suppression on the chest was quite high during back movements. A possible explanation for this observation is that the back movements, by the active contraction of muscles in the abdomen, may also have activated the chest muscles (Escamilla et al, 2006).…”