Progressive Resistance Exercise Training and Physical and Behavioural Health Components in Adults with Intellectual Disabilities: A Repeated Time-Series Design

This study, part of the PRET-study (NCT06579898), investigated changes in body composition, physical fitness, sarcopenia, activities of daily living (ADL), challenging behaviour, and falls in adults with intellectual disabilities (ID) following participation in a 24-week progressive resistance exercise training (PRET) intervention. A repeated-time-series design with one study group was used. We used multilevel linear regression models and non-parametric tests to investigate changes in body composition (bioelectrical impedance), physical fitness (ID-fitscan), sarcopenia, ADL (Barthel Index, Lawton IADL scale), challenging behaviour (Aberrant Behaviour Checklist), and falls. Thirty-six adults with mild to moderate ID (mean age: 55.6 ± 12.9 years; 52.8% male) participated and 26 completed the intervention. Intention-to-treat and per-protocol analyses showed statistically significant improvements in physical fitness and challenging behaviour. As these analyses concerned multiple secondary outcomes from a study powered for cardiovascular risk factors, these findings should be considered exploratory. Intention-to-treat analyses showed improvements in the five-times chair stand (−2.40 s, 95% CI [−4.06; −0.75]), and reductions in irritability (−1.10, 95% CI [−2.21; −0.00]) and inappropriate speech (−0.75, 95% CI [−1.22; −0.28]). No statistically significant changes were observed for body composition, ADL, or falls and no cases of sarcopenia were identified. The findings suggest that participation in PRET may be associated with improvements in lower body functional muscular endurance and challenging behaviour.