title: Method for assessing brain changes associated with gluteus maximus activation.
abstract: METHODS
  Reliability study.
  
  
  OBJECTIVE
  To determine the feasibility and reliability of using transcranial magnetic stimulation (TMS) to assess corticomotor excitability (CE) of the gluteus maximus.
  
  
  BACKGROUND
  Sport-specific skill training targeting greater utilization of the gluteus maximus has been proposed as a method to reduce the incidence of noncontact knee injuries. The use of TMS to assess changes in CE may help to determine training-induced central mechanisms associated with gluteus maximus activation.
  
  
  METHODS
  Within- and between-day reliability was measured in 10 healthy adults. The CE was measured by stimulating the gluteus maximus ìhotspotî at 120% and 150% of motor threshold, while subjects performed a double-leg bridge. An intraclass correlation coefficient (model 2,1), standard error of measurement, and minimal detectable change were calculated to determine the within- and between-day reliability for the following TMS variables: peak-to-peak motor-evoked potential (MEP) amplitudes, cortical silent period, and MEP latency.
  
  
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, USA.
authors.forename: Beth E
authors.initials: BE
authors.lastname: Fisher
authors.forename: Ya-Yun
authors.initials: YY
authors.lastname: Lee
authors.forename: Erica A
authors.initials: EA
authors.lastname: Pitsch
authors.forename: Brian
authors.initials: B
authors.lastname: Moore
authors.forename: Anna
authors.initials: A
authors.lastname: Southam
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Faw
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Powers
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology*; D002081:Buttocks / Q000502:physiology*; D004576:Electromyography; D015444:Exercise / Q000502:physiology; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000517:prevention & control; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D015203:Reproducibility of Results; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult