title: Reliability of a modified motor unit number index (MUNIX) technique.
abstract: BACKGROUND
  The purpose of this study was to examine the relative and absolute between-day reliability of the motor unit number index (MUNIX).
  
  
  METHODS
  Young, healthy adults (n=19) attended two testing sessions separated by 4-weeks where their maximal pinch-grip strength, MUNIX, and motor unit size index (MUSIX) were assessed in the abductor pollicis brevis muscle. Reliability was assessed by intraclass correlation coefficients (ICC), coefficient of variation (CV) and limits of agreement (LOA).
  
  
  RESULTS
  No mean differences were observed for MUNIX or MUSIX. The CV for the MUNIX and MUSIX measures were between 13.5% and 17.5%. The ICC for both measures were moderate to moderately-high (0.73-0.76), The LOA for both indicated a homoscedastic relationship.
  
  
  CONCLUSIONS
  Our findings indicate moderate to moderately-high reliability for both MUNIX and MUSIX. Future work is needed to ensure both measures are reliable in other muscles and cohorts, and further investigations are required to examine the validity of MUNIX.
authors.affiliation: Ohio Musculoskeletal and Neurological Institute (OMNI) at Ohio University, Athens, OH, United States; School of Applied Health Sciences and Wellness at Ohio University, Athens, OH, United States.
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Kaya
authors.affiliation: Ohio Musculoskeletal and Neurological Institute (OMNI) at Ohio University, Athens, OH, United States; Department of Biomedical Sciences at Ohio University, Athens, OH, United States.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Hoffman
authors.affiliation: Ohio Musculoskeletal and Neurological Institute (OMNI) at Ohio University, Athens, OH, United States; Department of Biomedical Sciences at Ohio University, Athens, OH, United States. Electronic address: clarkb2@ohio.edu.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Clark
mesh_terms: D000328:Adult; D004576:Electromyography / Q000379:methods*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D009046:Motor Neurons / Q000166:cytology* / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D052581:Pinch Strength / Q000502:physiology*; D011999:Recruitment, Neurophysiological / Q000502:physiology; D012016:Reference Values; D015203:Reproducibility of Results; D055815:Young Adult
keywords: EMG; MUNIX; MUSIX; Motor unit; Muscle