Author and graduation date: Melanie C. HARDIMAN, July, 1998

Committee members: Patricia Patterson (Chair), Denise L. Wiksten, Robert Pozos

Thesis title: EMG Muscle Activity in the Rectus Abdominus During a Curl-Up with and without an AB-Roller

Low back pain (LBP) has an enormous impact on our society. Finding preventive and rehabilitative measures for this medical disorder has fueled a line of research that examines the relationship between abdominal exercises and LBP. With the identification of the sit-up as risk to the low back and the lack of abdominal activity throughout a portion of the movement, the curl-up has been suggested as an alternative abdominal exercise. Through EMG research the curl-up has consistently shown the rectus abdominus as the primary muscle responsible for lifting the trunk up to 45 degrees. With the popularity of abdominal training, a new abdominal exercise device, the Ab-Roller, has been developed and claims to better isolate the rectus abdominus. To date, there is minimal research on the Ab-Roller. Thus, the purpose of this study was to compare the muscle activity, specifically the average EMG and EMG area under the curve, in the rectus abdominus during a curl-up with and without an Ab-Roller.

Eighteen adults, 10 men and 8 women, participated in this study. Participants performed 10 curl-ups with and without an Ab-Roller on separate days, with the order of testing randomly assigned. Analysis was performed on the second through the fifth CU for each condition. Reliability was excellent for the four EMG bursts with reliability coefficients ranging from R = .97 to R = .99. Results indicated a significant difference between the EMG area under the curve, F(1, 17) = 8.16, p <.05, with the Ab-Roller yielding significantly higher scores. In addition, a significant difference was reported in the average EMG between the two curl-ups, F(1, 17) = 10.56, p <.05. The sample was also split by gender to see if men and women were affected differently . Men showed a significant difference between the two trials. Conclusions drawn from this study report the Ab-Roller CU as an effective exercise for the rectus abdominus muscle. In fact, the Ab-Roller CU generated greater muscle activity with regard to the EMG area under the curve and the amplitude average EMG than did the traditional CU.

Limitations in current research on the Ab-Roller devices, and low back health and physical activity, specifically abdominal training, support the need for additional research. Further studies on the Ab-Roller are needed to provide accurate and objective information about the results of using these devices. In order to determine the effect of abdominal fitness has on LBP, a prospective study on low back patients and abdominal exercise, both with and without Ab-Rollers is recommended for future research. In addition, other muscles, such as the sternocleidomastoid, internal and external obliques, and paraspinals might be a focus of further research comparing the CU with and without an Ab-Roller.

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