Article

Many apparently independent older adults modify daily tasks. Task
modifications strongly predict future mobility disability. Clinically intuitive,
easily measured "biomarkers" associated with task modifications would offer
quantifiable treatment targets for prevention of age-related functional
limitations. OBJECTIVE: The objective of the study was to examine lower-extremity
muscle strength deficits and functionally relevant cutoff points associated with
daily task modifications in community dwelling older adults living independently.
DESIGN: This was a cross-sectional observational study. METHODS: Fifty-three
participants (mean age=76.4 years, SD=5.2) were tested for task modifications and
leg strength. Task modifications were assessed using a previously described tool
(summary task modification score). Twenty-six of the participants were classified
as task modifiers (TM group), and 27 participants were classified as non-task
modifiers (NTM group). A net antigravity leg force in the sagittal plane
(NETforce) was calculated by summing the normalized isometric and isokinetic
torques from the hip extensors, knee extensors, and ankle plantar flexors.
RESULTS: Compared with the NTM group, the TM group exhibited 30.0% and 33.5%
reduction in lower-extremity isometric and isokinetic NETforces, respectively.
Isometric and isokinetic NETforce cutoff points for task modifications were </=
4.24 and 2.77 N . m/kg body weight, respectively. The isometric and isokinetic
models both yielded sensitivity and specificity values of 74.1% and 80.8%,
respectively (positive likelihood ratio=3.852, 95% confidence
interval=1.699-8.735; negative likelihood ratio=0.321, 95% confidence
interval=0.167-0.618). Isometric and isokinetic NETforces were significantly
associated with task modifications (odds ratio=2.50 and 2.42, respectively).
LIMITATIONS: The cross-sectional design of this study does not allow for a test
of causal relationships. This study used a modest yet adequate sample size that
may limit generalization of the results. CONCLUSIONS: Isometric and isokinetic
NETforce cutoff points provide quantifiable biomarkers that discriminate
community-dwelling older adults who modify daily tasks from those who do not.

Langue : ANGLAIS