Heterogeneity of physical function responses to exercise training in older adults.
OBJECTIVE
To describe the interindividual variability in physical function responses to supervised resistance and aerobic exercise training interventions in older adults.


METHODS
Data analysis of two randomized, controlled exercise trials.


METHODS
Community-based research centers.


METHODS
Overweight and obese (body mass index (BMI)≥27.0 kg/m2) sedentary men and women aged 65 to 79 (N=95).


METHODS
Five months of 4 d/wk of aerobic training (AT, n=40) or 3 d/wk of resistance training (RT, n=55).


METHODS
Physical function assessments: global measure of lower extremity function (Short Physical Performance Battery (SPPB)), 400-m walk, peak aerobic capacity (VO2 peak), and knee extensor strength.


RESULTS
On average, both exercise interventions significantly improved physical function. For AT, there was a 7.9% increase in VO2 peak; individual absolute increases varied from 0.4 to 4.3 mL/kg per minute, and four participants (13%) showed no change or a decrease in VO2 peak. For RT, knee extensor strength improved an average of 8.1%; individual increases varied from 1.2 to 63.7 Nm, and 16 participants (30%) showed no change or a decrease in strength. Usual gait speed, 400-m walk time, chair rise time, and SPPB improved for the majority of AT participants and usual gait speed, chair rise time, and SPPB improved for the majority of RT participants, but there was wide variation in the magnitude of improvement. Only change in 400-m walk time with RT was related to exercise adherence (correlation coefficient=-0.31, P=.004).


CONCLUSIONS
Despite sufficient levels of adherence to both exercise interventions, some participants did not improve function, and the magnitude of improvement varied widely. Additional research is needed to identify factors that optimize responsiveness to exercise to maximize its functional benefits in older adults.
J. Paul Sticht Center on Aging and Rehabilitation, Wake Forest University, Winston-Salem, North Carolina; Section on Gerontology and Geriatric Medicine, Department of Internal Medicine, Wake Forest University, Winston-Salem, North Carolina.
Elizabeth A
EA
Chmelo
Charlotte I
CI
Crotts
Jill C
JC
Newman
Tina E
TE
Brinkley
Mary F
MF
Lyles
Xiaoyan
X
Leng
Anthony P
AP
Marsh
Barbara J
BJ
Nicklas
D000368:Aged; D015444:Exercise / Q000502:physiology*; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D055070:Resistance Training
aerobic training; muscle strength; peak aerobic capacity; resistance training; response variability