Thesis abstract:

«p»Purposes: To investigate the effects of lifestyle leisure-time physical activity [LTPA] and structured exercise [EXER] interventions on improving physical activity levels, muscle strength and functional capacity in adults with intellectual disability (ID) compared to usual care without PA intervention, and to compare the short- and long-term effects.«/p» «p»Methods: In this three-arm randomized controlled trial, participants were randomly recruited and allocated amongst the trial groups. Data were collected at baseline, 3 and 9 months after intervention. Physical activity (PA) was measured by multiple techniques including the International PA Questionnaire for people with ID (IPAQ-ID) and compared by weekly metabolic equivalent time (MET-minutes/week). Muscle strength was assessed using handgrip and isometric dynamometry, while functional capacity was measured using a six-minute walk test. Per-protocol statistical analyses were conducted using linear mixed model (LMM) techniques to investigate the association between outcomes and prespecified factors, to compare mean changes between different time points within a trial group and mean differences between groups at each time point. Subgroup analyses were carried out using t-test at each measurement time point for outcomes by age group, sex, body mass index (BMI), presence of Down syndrome and residential type.«/p» «p»«strong»Results«/strong»: A total of 96 participants were randomized into trial groups (32 for each). Of these, 14 were withdrawn from the trial. As the primary outcome for the study subjects analyzed by LMM, PA levels measured by IPAQ-ID had statistically significant associations with BMI (p = 0.049) and the interactions between measurement time and trial group (p = 0.036) revealed significant mean differences (MD) comparing [LTPA] (MD, 1338.7 MET-minutes/week; 95% CI: 472.3 to 2205.1; p = 0.003) and [EXER] (MD, 947.5 MET-minutes/week; 95% CI: 50.8 to 1844.2; p = 0.03) to the control group at 3 months after intervention. The LTPA group showed significant mean changes from baseline increasing at 3 months (MD 955.9 MET-minutes/week, 95% CI: 448.6 to 1463.1, p < 0.001) and 9 months (MD 955.9 MET-minutes/week, 95% CI, 448.6 to 1463.1, p < 0.001) after intervention. For the EXER group, significant mean changes were observed from baseline increasing at 3 months after intervention (MD 616.1 MET-minutes/week, 95% CI: 20.6 to 1211.6, p = 0.043). Muscle strength revealed significant improvements on all measures (leg, elbow and grip strengths). In the LTPA group, functional capacity was also significantly improved, demonstrating greater mean walked distance from baseline at 3 months (MD 40.7 meters, 95% CI: 22.0 to 59.3, p < 0.001) and 9 months (MD 40.4 meters, 95% CI: 16.2 to 20.6, p = 0.001) after intervention. The walked distance changed significantly with the interaction between measurement time and trial group (p < 0.05). No adverse events or harm were reported.«/p» «p»Conclusions: Our findings indicate that both lifestyle LTPA and structured exercise programs have short- and long-term improvement on PA levels, muscle strength and functional capacity in adults with ID. The lifestyle LTPA approach seemed to have better effects and sustainability of improving PA participations in the long term while the structured exercise may be more appropriate in improving muscle strength and functional capacity.«/p»