title: A simple method to determine body segment masses in vivo: reliability, accuracy and sensitivity analysis.
abstract: OBJECTIVE
  To show that force plates can be used to quickly acquire subject-specific segment mass data.
  
  
  METHODS
  In vivo measurements were performed on subjects belonging to three populations: female varsity swimmers, female varsity volleyball players, and male college students. Segmental masses were measured using a force plate technique, and were compared with published data.
  
  
  BACKGROUND
  Patients from populations for which data from the literature are not applicable (e.g. pathological, aging females, obese, children, etc.) would benefit from a direct measure of inertial parameters for accurate joint moment calculations.
  
  
  METHODS
  Eight female varsity volleyball players, 17 female varsity swimmers, and 10 male college students were measured anthropometrically. They then lay on a board placed on a force plate and the center of pressure was recorded while the subjects adopted various prescribed limb positions. Their limb masses were subsequently calculated from the center of pressure data given estimated center of mass locations.
  
  
  RESULTS
  The method was highly reproducible with an average reliability coefficient of 0.83 and yielded results similar to those of published methods. Significantly different mass distributions were found between the two female populations tested (P<0.025).
  
  
  CONCLUSIONS
  The method can quickly provide subject-specific limb segment mass information.
  
  
  CONCLUSIONS
  Measuring subjects' segment masses individualizes clinical assessments and may be necessary for those from special populations to avoid erroneous biomechanical conclusions.
authors.affiliation: Biomechanics Laboratory, The Pennsylvania State University, 39 Recreation Building, University Park, PA 16802, USA. tcp120@psu.edu
authors.forename: Todd C
authors.initials: TC
authors.lastname: Pataky
authors.forename: Vladimir M
authors.initials: VM
authors.lastname: Zatsiorsky
authors.forename: John H
authors.initials: JH
authors.lastname: Challis
mesh_terms: D000328:Adult; D000886:Anthropometry / Q000379:methods*; D001824:Body Constitution / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology*; D011312:Pressure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical