Abstract
OBJECTIVES: To examine the effects of 12 weeks aquatic high-intensity interval training (AHIIT) compared with aquatic moderate-intensity continuous training (AMICT) on aerobic capacity and lower limb functional strength in adults with rheumatic and musculoskeletal diseases (RMDs). DESIGN: An assessor-blinded randomised controlled trial. SETTING: Community-based setting. PARTICIPANTS: 89 participants (91% female, mean age 62 (SD 13) years) with RMDs were randomly allocated to AHIIT (n=44) or AMICT (n=45). INTERVENTIONS: Both groups participated in group-based peer-led exercise programmes two times per week for 12 weeks. The AHIIT group included four intervals of 4 min at high intensity (Borg scale 14-18). The AMICT group maintained moderate continuous intensity level (Borg scale 12-13). MAIN OUTCOME MEASURES: Peak aerobic capacity (VO(2)peak) was estimated by time to exhaustion and lower limb functional strength with the 30-second sit-to-stand test (30sSTS) at baseline, 3 months and 6 months. A linear mixed model for repeated measures estimated the mean difference with 95% CI in VO(2)peak and 30sSTS. RESULTS: Mean exercise intensity was Borg scale 15 (SD 2) and 13 (SD 2) in the AHIIT and AMICT, respectively. Mean improvement in VO(2)peak in AHIIT was 1.9 mL∙kg(-1)∙min(-1) (95% CI 0.045 to 3.77) compared with AMICT after 12 weeks (p<0.05). There was no statistically significant difference between groups in VO(2)peak after 6 months or in 30sSTS at either 3 or 6 months (p>0.05). No adverse events during exercise were reported. CONCLUSIONS: AHIIT demonstrated significant improvements in aerobic capacity after 12 weeks, and the intervention was well tolerated with no adverse events reported. However, there was no maintenance of aerobic capacity at 6 months. TRIAL REGISTRATION NUMBER: NCT05209802.