Crunch and hypopressive abdominal gymnastics : activated muscles and immediate effects on diastasis recti

Introduction: In postpartum, many women complain of various disorders such as the Diastasis Recti (DR) and the abdominal ptosis which constitute an aesthetic problem. To treat these disorders Crunch and Hypopressive Abdominal Gymnastics (HAG) are used. What is the acute effect of these exercises on the DR and which muscles do they activate? Method: Twenty-two nulliparous students and 19 women who have given birth participated to the study. We used electromyography to measure the activation of abdominal muscles during different movements involving Crunch and HAG. Dial caliper was used to measure the DR. Results: The DR was significantly decreased by 6 mm during the Crunch compared to the Head up position. When the HAG was associated with the Crunch, no decrease was observed. No difference was observed between the Crunch and the Exaggerated Crunch. The Crunch activated the Rectus Abdominis (RA) to 48% and the Transversus Abdominis (TA) to 61%. When the Crunch was combined with the HAG, the RA activity decreased to 19% and the TA activity increased to 88%. The HAG activated the TA to 71% in phase 1 and 55% in phase 2. The DR decrease was correlated with the RA activity. Discussion: The TA activity during the Crunch is involuntary and probably reflex, while activation of the TA during the HAG is voluntary and concentric. Conclusion: The best exercise to acutely reduce the DR and activate all abdominal muscles is the Crunch. Long term effect of a training program must be measured.