To describe the inter-individual variability in physical function responses to supervised, resistance and aerobic exercise training interventions in older adults.
Ninety-five older (65–79 years), overweight and obese (body mass index [BMI] ≥27 kg/m2), sedentary men and women.
Five-months of either 4 d/wk of aerobic training (AT, n=40) or 3 d/wk of resistance training (RT, n=55).
Physical function assessments: global measure of lower extremity function (short physical performance battery; SPPB), 400-meter walk, peak aerobic capacity (VO2peak), and knee extensor strength.
On average, both exercise interventions significantly improved physical function. For AT, there was a 7.9% increase in VO2peak; individual absolute increases varied from 0.4–4.3 ml/kg/min and four participants (13%) showed no change or a decrease in VO2peak. For RT, knee extensor strength improved an average of 8.1%, but individual increases varied from 1.2–63.7 Nm, and 16 participants (30%) showed no change or a decrease in strength. Majority of participants improved 400-m walk time, usual gait speed, chair rise time, and SPPB with AT, and improved usual gait speed, chair rise time, and SPPB with RT; but, there was wide variation in the magnitude of improvement. Compliance was only related to change in 400-m walk time following RT (r= −0.31; p<0.05).
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.