TY - JOUR
T1 - Aging, regularity and variability in maximum isometric moments
AU - Challis, John H.
N1 - Funding Information:
The author would like to thank Dr. David Proctor, Khoi Le, Jennifer Muri, and Samantha Winter for their assistance with subject recruitment and data collection. Some of the testing used the facilities of the General Clinical Research Center of The Pennsylvania State University whose support is acknowledged. This research was in part supported by a grant from The Whitaker Foundation, and the National Institute of Health Grants MO1-RR-10732 (GCRC).
PY - 2006
Y1 - 2006
N2 - This study examined the variability and regularity of maximum isometric moment production of the plantar flexors in young and old subjects. It was hypothesized that in the development of maximum isometric moments there would be greater regularity in the moment profiles for older subjects compared with young subjects, due to the reduced number of motor units present in elderly muscle. Two groups of subjects produced three maximal isometric plantar flexions (young: n = 11, mean age 23.8±2.8 years, mean mass 81.2±10.4 kg, mean height 1.78±0.05 m; elderly: n = 13, mean age 74.0±3.3 years, mean mass 78.5±3.4 kg, mean height 1.73±0.05 m). The plateau of the moment-time curve was analyzed for each trial. A repeat measures analysis of variance showed the young subjects produced statistically greater peak plantar flexion moments than the elderly subjects, but similar coefficients of variation. Signal regularity was determined by computing the signal's approximate entropy, which demonstrated that the older group had greater regularity in their generation of moment profiles. The hypothesis was accepted, with a potential explanation for this increased regularity in old age being the reduced number of motor units to coordinate.
AB - This study examined the variability and regularity of maximum isometric moment production of the plantar flexors in young and old subjects. It was hypothesized that in the development of maximum isometric moments there would be greater regularity in the moment profiles for older subjects compared with young subjects, due to the reduced number of motor units present in elderly muscle. Two groups of subjects produced three maximal isometric plantar flexions (young: n = 11, mean age 23.8±2.8 years, mean mass 81.2±10.4 kg, mean height 1.78±0.05 m; elderly: n = 13, mean age 74.0±3.3 years, mean mass 78.5±3.4 kg, mean height 1.73±0.05 m). The plateau of the moment-time curve was analyzed for each trial. A repeat measures analysis of variance showed the young subjects produced statistically greater peak plantar flexion moments than the elderly subjects, but similar coefficients of variation. Signal regularity was determined by computing the signal's approximate entropy, which demonstrated that the older group had greater regularity in their generation of moment profiles. The hypothesis was accepted, with a potential explanation for this increased regularity in old age being the reduced number of motor units to coordinate.
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U2 - 10.1016/j.jbiomech.2005.04.008
DO - 10.1016/j.jbiomech.2005.04.008
M3 - Article
C2 - 15946669
AN - SCOPUS:33646403431
SN - 0021-9290
VL - 39
SP - 1543
EP - 1546
JO - Journal of Biomechanics
JF - Journal of Biomechanics
IS - 8
ER -