Exploring the Interrelationships Between Physical Function, Functional Exercise Capacity, and Exercise Self-Efficacy in Persons Living with HIV.

PURPOSE: To determine if there were differences between the subjective and objective assessments of physical activity while controlling for sociodemographic, anthropometric, and clinical characteristics.

SETTING/SAMPLE: A total of 810 participants across eight sites located in three countries.

MEASURES: Subjective instruments were the two subscales of Self-efficacy for Exercise Behaviors Scale: Making Time for Exercise and Resisting Relapse and Patient-Reported Outcomes Measurement Information System, which measured physical function. The objective measure of functional exercise capacity was the 6-minute Walk Test.

ANALYSIS: Both univariate and multivariant analyses were used.

RESULTS: Physical function was significantly associated with Making Time for Exercise (β = 1.76, p  = .039) but not with Resisting Relapse (β = 1.16, p  = .168). Age (β = -1.88, p  = .001), being employed (β = 16.19, p  < .001) and race (βs = 13.84-31.98, p  < .001), hip-waist ratio (β = -2.18, p  < .001), and comorbidities (β = 7.31, p  < .001) were significant predictors of physical functioning. The model predicting physical function accounted for a large amount of variance (adjusted R 2  = .938). The patterns of results predicting functional exercise capacity were similar. Making Time for Exercise self-efficacy scores significantly predicted functional exercise capacity (β = 0.14, p  = .029), and Resisting Relapse scores again did not (β = -0.10, p  = .120). Among the covariates, age (β = -0.16, p  < .001), gender (β = -0.43, p  < .001), education (β = 0.08, p  = .026), and hip-waist ratio (β = 0.09, p  = .034) were significant. This model did not account for much of the overall variance in the data (adjusted R 2  = .081). We found a modest significant relationship between physical function and functional exercise capacity ( r  = 0.27).

CONCLUSIONS: Making Time for Exercise Self-efficacy was more significant than Resisting Relapse for both physical function and functional exercise capacity. Interventions to promote achievement of physical activity need to use multiple measurement strategies.