Electromyographic Response Of The Abdominal Muscles During Curl-up Exercises With Different Loads

Abstract

Aim. The present study focuses on the behavior of the abdominal muscles when performing curl-ups with loads gauged in relation to a maximum load test (1 RM). Methods. Thirteen subjects performed curl-up exercises with loads equivalent to 80, 60, 40 and 20% of the 1 RM (100%) maximum, with 5-minute rests between sets. Surface bipolar EMG electrodes were placed on the right and left Rectus Abdominis and the Obliquus Externus muscle. Differences between loads and repetitions were determined using the Shapiro-Wilk, ANOVA (Friedman) and Wilcoxon tests (P<0.05). Results. The root mean square (RMS) of the EMG was calculated for the first four and the last three repetitions. The percentage values for the abdominal muscles studied were then averaged and the result was used to represent abdominal synergy (AbSyn). Conclusion. Considering AbSyn to be a representative measure of the abdominal muscles in general, we concluded that the abdominal muscles were more strongly recruited in the 100% category than under any other external load conditions. Overall, the most significant differences were between the 20% load and the other loads. Furthermore, as recognized in the literature, to maximize safety during the performance of abdominal exercises and minimize the compression of the lumbar spine, the use of heavy loads during the movement is not indicated. When using loads, therefore, we suggest giving priority to those in the 20% and 40% ranges.1685289296Edgerton, V.R., Roy, R.R., Regulation of skeletal muscle fiber size, shape and function (1991) J Biomech, 24, pp. 123-133Enoka, R.M., (2000) Bases neuromecânicas da cinesiologia, , 2nd ed. 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