Changes in Muscle Activity of Hip Joint Muscles during Clam Exercise after Abdominal Draw in Exercise in Men with Weak Abdominal Muscles

Background Strengthening the gluteus medius (Gmed) is vital to provide functional movement of the lower extremities and lateral stability of the pelvis. The clam exercise (CE) effectively activates the Gmed. To perform the CE effectively, it is essential to control the lumbar-pelvic movement, which is influenced by the stability of the lumbar pelvis. Purpose The purpose of this study was to compare the effects on muscle activity of the internal oblique (IO), Gmed, gluteus maximus (Gmax), and tensor fascia lata (TFL) between men with weak abdominal muscles (WAM) and healthy men during the CE after performing the abdominal draw-in maneuver (ADIM). Study design Cross-sectional study Methods Participants in this study included 11 men with WAM and 11 healthy men. The IO, Gmed, Gmax, and TFL activities were measured on all participants using wireless electromyography during the CE before the intervention. Both groups performed ADIM for 10 minutes, and each muscle activity was measured again similarly. A paired t-test was used to compare before and after intervention within groups, and an independent t-test was used to compare between groups. Results In the intra-group comparison of the WAM group, the muscle activity of IO, Gmed, and Gmax significantly increased and the TFL activity significantly decreased during CE after performing ADIM. In contrast to groups before the intervention, TFL activity was significantly higher in the WAM group than in the control group. In a comparison between groups, the amount of change in the activity of Gmed and TFL was more significant in the WAM group than in the control group. Conclusions Results suggested that for men with WAM, performing the ADIM before the CE is an effective exercise method for reducing the compensatory action of TFL and increasing the selective activity of Gmed and Gmax.