Predictors of adherence to physical activity in the Lifestyle Interventions and Independence for Elders pilot study (LIFE-P)

Figures & data

Table 1 Grouping of variables for multiple regression analyses

Participant demographics	Disease burden	Physical functioning	Self-reported symptoms	Social cognitive measures
Education Age Sex Race	Arthritis Heart attack Heart failure Pacemaker Lung disease Cancer Diabetes BMI	Grip Strength 400M Walk SPPB-Chair SPPB-Balance SPPB-Walk	Pain severity Pain frequency Energy/fatigue Depression	Body satisfaction Desire for PC Barriers efficacy 400M Walk efficacy Goal setting efficacy

Legend. BMI = Body Mass Index; SPPB = Short Physical Performance Battery; PC = Physical Competence.

Table 2 Description of activities for the physical activity intervention

Major components with brief description of time and content

Warm-up and cool down ∼5 minutes each Hamstring and calf stretch Quadriceps stretch Chest and arm stretch Upper back stretch Walking ∼30 minutes (RPE target of 12–14) Strength training ∼10 minutes (2 sets of 10 repetitions; 3X each week; RPE target of 15–16) Squats into a chair Standing leg curls with ankle weights Knee extensions with ankle weights Hip side raises with ankle weights Toe stands 4. Balance ∼10 minutes (3X each week) Hip circles with hand support Two foot toe stands with hand support One foot toe stands with hand support Side steps with hand support

Note: Prescriptions were individualized for each participant. Balance exercises were made more challenging based on individual abilities. Details of the intervention may be obtained from the first author.

Table 3 Descriptive characteristics on total sample and treatment arms

Variables	Total randomized (N = 424)	Physical activity (n = 213)	Successful aging (n = 211)	p-value
Age	76.77 ± 4.24	76.53 ± 4.17	77.01 ± 4.31	0.241
Race/Ethnicity				0.865
African American	77 (18.2%)	37 (17.4%)	40 (19.0%)
Caucasian	315 (74.3%)	160 (75.1%)	155 (73.5%)
Latino, Hispanic or Spanish	20 (4.7%)	10 (4.7%)	10 (4.7%)
Other/mixed	11 (2.6%)	6 (2.8%)	5 (2.4%)
Refused/missing	1 (0.2%)	0 (0.0%)	1 (0.5%)
Sex				0.885
Women	292 (68.9%)	146 (68.5%)	146 (69.2%)
Men	132 (31.1%)	67 (31.5%)	65 (30.8%)
Education				0.856
< High school	11 (2.6%)	5 (2.3%)	6 (2.8%)
High school	116 (27.4%)	58 (27.2%)	58 (27.5%)
>High school	284 (67.0%)	142 (66.7%)	142 (67.3%)
Other	13 (3.1%)	8 (3.8%)	5 (2.4%)
Marital status				0.647
Married	167 (39.4%)	78 (36.6%)	89 (42.2%)
Separated	2 (0.5%)	1 (0.5%)	1 (0.5%)
Divorced	63 (14.9%)	36 (16.9%)	27 (12.8%)
Widowed	173 (40.8%)	86 (40.4%)	87 (41.2%)
Never married	16 (3.8%)	10 (4.7%)	6 (2.8%)
Other	3 (0.7%)	2 (0.9%)	1 (0.5%)
Body mass index	30.33 ± 6.53	30.78 ± 6.90	29.87 ± 6.11	0.149
Arthritis	93 (21.98%)	50 (23.47%)	43 (20.48%)	0.766
Heart attack	39 (9.20%)	24 (11.27%)	15 (7.11%)	0.138
Congestive heart failure	24 (5.66%)	11 (5.16%)	13 (6.16%)	0.657
Hypertension	293 (69.10%)	148 (69.48%)	145 (68.72%)	0.865
Cancer	74 (17.45%)	38 (17.84%)	36 (17.06%)	0.833
Diabetes	92 (21.70%)	58 (27.23%)	34 (16.11%)	0.005
SPPB score	7.52 ± 1.42	7.57 ± 1.45	7.46 ± 1.38	0.432

Table 4 Composite backwards elimination regression model: adoption phase

Variable	Variables considered in full model1			Variables in final composite model2
	Parameter estimate	Standard error	Pr > F	Parameter estimate	Standard error	Pr > F
Intercept	44.28477	41.19629	0.2838	82.76922	32.99849	0.0129
Education:≤HS	−3.30956	3.62463	0.3624	−3.42198	3.63993	0.3483
Age	0.03313	0.43432	0.9393	−0.22487	0.40248	0.5770
Sex	0.97809	3.64094	0.7885	0.24664	3.51056	0.9441
Race: African Am.	−10.40696	6.98646	0.1380	−10.14982	6.94055	0.1452
Race: Caucasian	−4.71209	6.14355	0.4440	−5.58722	6.12545	0.3628
Heart attack	3.98726	5.22117	0.4460
Heart failure	−8.99803	6.84445	0.1902
Lung disease	−9.99246	4.54259	0.0290	−10.93624	4.52088	0.0165
BMI	0.34994	0.26113	0.1818
SBBP balance	2.41263	1.55958	0.1235
Desire for PC	−2.98340	2.42773	0.2206
Barriers efficacy	2.01188	0.98745	0.0430	2.14358	0.82063	0.0097
400M walk efficacy	0.11452	0.09994	0.2533

¹ Exceeded 0.15 criterion for separate models.

² Exceeded 0.05 criterion for composite model; demographic variables were forced into this model.

Table 5 Composite backwards elimination regression model: Transition phase1

Variable	Parameter estimate	Standard error	Pr > F
Intercept	55.16368	35.07646	0.1175
Education:≤HS	−9.38245	4.20131	0.0267
Age	0.40031	0.46141	0.3867
Sex	1.58985	4.05115	0.6952
Race: African Am.	−14.45430	7.92090	0.0696
Race: Caucasian	−2.79435	6.98583	0.6896
Pacemaker	23.75471	11.91198	0.0476
400m Walk Time	−2.30496	1.00084	0.0224

¹ The results of the full and composite models were identical in the transition phase. All variables exceeded 0.05 criterion and demographic variables were forced into this model.

Table 6 Composite backwards elimination regression model: Maintenance phase

	Variables considered in full model1			Variables in final composite model2
Variable	Parameter estimate	Standard error	Pr > F	Parameter estimate	Standard error	Pr > F
Intercept	3.87855	2.93445	0.1879	2.23806	2.49019	0.3699
Education:≤HS	−0.01535	0.29013	0.9579	−0.03575	0.29022	0.9021
Age	−0.01319	0.03276	0.6878	−0.00032	0.03105	0.9917
Sex	0.47334	0.28212	0.0951	0.55766	0.27761	0.0460
Race: African Am.	−0.61303	0.53549	0.2538	−0.55341	0.53781	0.3048
Race: Caucasian	0.53260	0.47417	0.2628	0.66529	0.47509	0.1631
Arthritis	0.48057	0.31151	0.1246
Pacemaker	1.52088	0.83106	0.0689	1.81371	0.82327	0.0288
BMI	−0.03365	0.02118	0.1139
Energy/Fatigue	0.28169	0.13101	0.0328	0.31509	0.12676	0.0138
Barriers Efficacy	0.08240	0.06557	0.2105

¹ Exceeded 0.15 criterion for separate models.

² Exceeded 0.05 criterion for composite model; demographic variables were forced into this model.