Evaluation of recommended maximum voluntary contraction exercises for back muscles commonly investigated in ergonomics

Maximum voluntary contraction (MVC) exercises are commonly employed for normalizing electromyography (EMG) data to enable comparisons between different individuals and muscles. The purpose of this research was to test various recommended MVC exercises for two commonly investigated back muscles in ergonomics and, based on EMG results, determine the most appropriate exercise for each muscle. Through a preliminary review, these two muscles were identified as the lumbar erector spinae (LES) and thoracic erector spinae (TES). Fifteen healthy male participants were recruited. Five different recommended MVC exercises were performed for both muscles, including declined trunk extension, prone trunk extension, standing trunk extension, hip extension, and the arch test. Results showed that no single exercise was capable of eliciting the highest EMG amplitude in all the participants. The largest EMG average was reported using hip extension for the LES and prone trunk extension for the TES; however, no statistically significant differences were detected between them and other exercises, apart from declined trunk extension. Overall, the arch test showed the most favorable results for both the LES and TES, in that it: had a high EMG average; was the most consistent to elicit the highest EMG amplitude in participants; and had relatively low variability.