It has been proposed that strengthening and skill training of gluteus maximus (GM) may be beneficial in treating various knee injuries. Given the redundancy of the hip musculature and the small representational area of GM in the primary motor cortex (M1), learning to activate this muscle before prescribing strength exercises and modifying movement strategy would appear to be important. This study aimed to determine whether a short-term activation training program targeting the GM results in neuroplastic changes in M1. Using transcranial magnetic stimulation, motor evoked potentials (MEPs) were obtained in 12 healthy individuals at different stimulation intensities while they performed a double-leg bridge. Participants then completed a home exercise program for ∼1 h/day for 6 days that consisted of a single exercise designed to selectively target the GM. Baseline and post-training input-output curves (IOCs) were generated by graphing average MEP amplitudes and cortical silent period durations against corresponding stimulation intensities. Following the GM activation training, the linear slope of both the MEP IOC and cortical silent period IOC increased significantly. Short-term GM activation training resulted in a significant increase in corticomotor excitability as well as changes in inhibitory processes of the GM. We propose that the observed corticomotor plasticity will enable better utilization of the GM in the more advanced stages of a rehabilitation/training program.

T T RESULTS:It is feasible to measure the CE of the gluteus maximus with TMS. The intraclass correlation coefficients for all TMS outcome measures ranged from 0.73 to 0.97. The ranges of minimal detectable change, with respect to mean values for each TMS variable, were larger for MEP amplitude (304.7-585.4 µV) compared to those for cortical silent period duration (25.3-40.8 milliseconds) and MEP latency (1.1-2.1 milliseconds). T T CONCLUSION:The present study demonstrated a feasible method for using TMS to measure CE of the gluteus maximus. Small minimal detectable change values for the cortical silent period and MEP latency provide a reference for future studies.