Table 3.

Relations of physical activity to physical performance, by age group.

Phys.Perf.	Physical activity variable	Model	Total sample		P for INT by age	Age 50–64 (n = 408)		Age 65–74 (n = 665)		Age ≥ 75 (n = 287)
			B est. ± SE	p		B est. ± SE	p	B est. ± SE	p	B est. ± SE	p
Gait speed (m/s)	Steps (1000 steps)	1	0.006 ± 0.001	0.0001	0.032	0.004 ± 0.003	0.148	0.004 ± 0.002	0.037	0.011 ± 0.003	0.0005
		2	0.003 ± 0.001	0.018	–	0.001 ± 0.002	0.612	0.002 ± 0.002	0.359	0.009 ± 0.003	0.006
	SED	1	−0.005 ± 0.001	< 0.0001	0.027	−0.003 ± 0.001	0.031	−0.004 ± 0.001	0.002	−0.008 ± 0.002	< 0.0001
	(1% or ~10 min)	2	−0.004 ± 0.001	< 0.0001	–	−0.002 ± 0.001	0.127	−0.003 ± 0.001	0.021	−0.007 ± 0.002	0.0003
		2 + MVPA	0.0002 ± 0.001	0.876	–	0.001 ± 0.002	0.518	0.001 ± 0.001	0.505	−0.002 ± 0.002	0.327
Chair stand time (log)	Steps (1000 steps)	1	−0.010 ± 0.002	< 0.0001	0.266	–	–	–	–	–	–
		2	−0.007 ± 0.002	0.0002	–	–	–	–	–	–	–
	SED	1	0.006 ± 0.001	< 0.0001	0.071	0.005 ± 0.002	0.011	0.005 ± 0.002	0.004	0.010 ± 0.003	0.0004
	(1% or ~10 min)	2	0.005 ± 0.001	< 0.0001	–	0.003 ± 0.002	0.147	0.004 ± 0.002	0.013	0.009 ± 0.003	0.002
		2 + MVPA	0.001 ± 0.001	0.596	–	−0.002 ± 0.002	0.406	0.0003 ± 0.002	0.861	0.005 ± 0.004	0.221
Handgrip (kg) men	Steps (1000 steps)	1	−0.16 ± 0.09	0.077	0.016	−0.54 ± 0.19	0.004	−0.07 ± 0.13	0.570	0.22 ± 0.16	0.163
		2	−0.19 ± 0.09	0.043		−0.54 ± 0.20	0.007	−0.14 ± 0.13	0.302	0.20 ± 0.16	0.223
	SED	1	0.09 ± 0.05	0.088	0.034	0.27 ± 0.10	0.010	−0.01 ± 0.07	0.844	0.08 ± 0.10	0.444
	(1% or ~10 min)	2	0.10 ± 0.05	0.049	–	0.26 ± 0.11	0.019	0.01 ± 0.07	0.861	0.11 ± 0.11	0.280
		2 + MVPA	0.19 ± 0.06	0.001	–	0.41 ± 0.12	0.0008	0.04 ± 0.09	0.671	0.30 ± 0.12	0.013
Handgrip (kg) women	Steps (1000 steps)	1	0.09 ± 0.06	0.125	0.711	–	–	–	–	–	–
		2	0.11 ± 0.06	0.078		–	–	–	–	–	–
	SED	1	−0.05 ± 0.04	0.133	0.025	−0.03 ± 0.06	0.682	−0.001 ± 0.05	0.992	−0.25 ± 0.09	0.004
	(1% or ~10 min)	2	−0.05 ± 0.04	0.147	–	−0.01 ± 0.06	0.883	0.02 ± 0.05	0.775	−0.27 ± 0.09	0.003
		2 + MVPA	0.06 ± 0.05	0.165	–	0.06 ± 0.08	0.421	0.01 ± 0.07	0.053	−0.14 ± 0.12	0.233

Abbreviations: Physical performance measure (Phys. Perf.); moderate to vigorous physical activity (MVPA); sedentary time as a percent of wear time (SED [%]); standard error (SE); interaction (INT).

The following variables were log-transformed: chair stand time and MVPA. Beta estimate (B est.) is in units of physical performance variable per physical activity variable difference. For the outcomes gait speed and handgrip strength, higher is better. For chair stand time, lower is better.

Model 1: adjusted for age, sex, cohort, wear time, season of physical activity monitor worn, residence in New England or other.

Model 2 (in addition to Model 1 adjustments): body mass index, diabetes, cardiovascular disease, hypertension, current smoking, cancer.

Interaction significance was tested only for model 1. Significant p-values were bolded for significance (p < 0.05 for regression and p < 0.1 for interaction analysis).