title: In vivo measurement of hindlimb neuromuscular function in mice.
abstract: BACKGROUND
  In vitro or in situ methods to assess neuromuscular performance in rodents are invasive and inadequate to fully assess large hindlimb muscles.
  
  
  METHODS
  An in vivo hindlimb exertion force test (HEFT) was developed to quantify muscle function peak force (PF), peak rate of force development (PRFD), and short- and long-latency reaction times (SLRT and LLRT, respectively) in C57BL/6J mice.
  
  
  RESULTS
  PF did not change with one- and three-times-per-week repeated HEFT trials, demonstrating assessment reproducibility. However, PRFD decreased with trial, indicating that mice modified response behavior while achieving the same PF. Separately, mice were subjected to 14 days of hindlimb suspension (HS) to induce muscle atrophy. Concomitant with decreased lean carcass and individual muscle masses, HS mice showed reduced PF and LLRT.
  
  
  CONCLUSIONS
  The results demonstrate that HEFT is an effective tool for evaluating in vivo hindlimb neuromuscular performance due to disuse muscle atrophy and potentially for other disease and injury models.
authors.affiliation: BioServe Space Technologies, Aerospace Engineering Sciences, UCB 429, University of Colorado, Boulder, Colorado 80309, USA. stodieck@colorado.edu
authors.forename: Louis S
authors.initials: LS
authors.lastname: Stodieck
authors.forename: Brooke J
authors.initials: BJ
authors.lastname: Greybeck
authors.forename: Cara M A
authors.initials: CM
authors.lastname: Cannon
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Hanson
authors.forename: Mary H
authors.initials: MH
authors.lastname: Young
authors.forename: Steve J
authors.initials: SJ
authors.lastname: Simske
authors.forename: Virginia L
authors.initials: VL
authors.lastname: Ferguson
mesh_terms: D000465:Algorithms; D000818:Animals; D003627:Data Interpretation, Statistical; D006614:Hindlimb / Q000294:innervation* / Q000473:pathology / Q000502:physiology*; D019417:Hindlimb Suspension / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000294:innervation / Q000473:pathology / Q000502:physiology*; D009133:Muscular Atrophy / Q000473:pathology; D009474:Neurons / Q000502:physiology*; D009482:Neurophysiology / Q000295:instrumentation* / Q000379:methods*; D009929:Organ Size / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012018:Reflex / Q000502:physiology; D015203:Reproducibility of Results; D014741:Video Recording