Muscle power of the ankle flexors predicts functional performance in community-dwelling older women.
OBJECTIVE
To test the hypothesis that peak power of the ankle flexors is related to physical functioning in older women with functional limitations.


METHODS
A cross-sectional study.


METHODS
University-based human physiology laboratory.


METHODS
Thirty-four older women (75.4 +/- 5.1 years, 67.8 +/- 11.3 kg, body mass index 27.4 +/- 4.5) with self-reported functional limitations.


METHODS
Plantarflexion (PF) and dorsiflexion (DF) peak power and isometric strength with physical performance (stair climb time, repeated chair rise time, maximal and habitual gait velocity) were determined. An isokinetic dynamometer was used to measure isometric strength, isokinetic peak torque and power of PF and DF at five angular velocities (30 degrees, 60 degrees, 90 degrees, 120 degrees, and 180 degrees.sec-1), and isometric strength.


RESULTS
Peak torque for both PF and DF declined with increasing velocity of movement (PF: P <.0001; DF: P <.0001), whereas peak power increased with increasing velocity up to 120 degrees.sec-1. The strongest univariate associations were found between chair rise time and DF peak power (r = 0.50; P <.002), stair climb time and DF peak power (r = 0.49; P <.003), habitual gait velocity and PF isometric strength (r = 0.53; P <.001), and maximal gait and PF isometric strength (r = 0.47; P <.005). Multivariate regression analysis revealed that DF and PF peak power along with the physical functioning and general health scores from the Medical Outcomes Study Short Form were independent predictors of chair and stair climb performance.


CONCLUSIONS
These data suggest that ankle muscle power together with self-reported measures of health and physical functioning are essential components of functional mobility in older women with functional limitations.
Suzuki
T
T
Human Physiology Laboratory, Department of Health Sciences, Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, Massachusetts 02215, USA.
Bean
J F
JF
Fielding
R A
RA
D000203:Activities of Daily Living; D000368:Aged / Q000502:physiology*; D000369:Aged, 80 and over; D000842:Ankle / Q000502:physiology*; D001900:Boston / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait; D006304:Health Status; D006801:Humans; D007537:Isometric Contraction; D015999:Multivariate Analysis; D018482:Muscle, Skeletal / Q000502:physiology*; D011187:Posture; D012044:Regression Analysis; D013997:Time Factors; D019415:Torque