A simple method to determine body segment masses in vivo: reliability, accuracy and sensitivity analysis.
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.
Pataky
Todd C
TC
Biomechanics Laboratory, The Pennsylvania State University, 39 Recreation Building, University Park, PA 16802, USA. tcp120@psu.edu
Zatsiorsky
Vladimir M
VM
Challis
John H
JH
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