title: Evidence of altered corticomotor excitability following targeted activation of gluteus maximus training in healthy individuals.
abstract: 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.
authors.affiliation: aDivision of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, California, USA bSchool and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Beth E
authors.initials: BE
authors.lastname: Fisher
authors.forename: Anna C
authors.initials: AC
authors.lastname: Southam
authors.forename: Yi-Ling
authors.initials: YL
authors.lastname: Kuo
authors.forename: Ya-Yun
authors.initials: YY
authors.lastname: Lee
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Powers
mesh_terms: D000328:Adult; D013181:Cortical Spreading Depression / Q000502:physiology*; D004576:Electromyography; D019054:Evoked Potentials, Motor / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology; D050781:Transcranial Magnetic Stimulation / Q000379:methods; D055815:Young Adult