Effectiveness of exercise snack (short duration vigorous intermittent physical activity) on cardiovascular and metabolic parameters in Inflammatory myopathy: A randomized controlled trial

Patients with idiopathic inflammatory myositis (IIM) who are in clinical remission, on stable dose immunosuppressants, are under follow up and regular care  in the department of Clinical Immunology OPD will be screened for eligibility. If the patients satisfy the inclusion criteria and provide written informed consent, they will be enrolled into the trial.

Baseline clinical information namely age/sex, type of IIM, duration of IIM disease, disease manifestation (arthritis, cutaneous signs, interstitial lung disease), and myositis specific antibodies, myositis associated antibodies will be recorded. The disease activity measures as determined by manual muscle testing 8 (MMT8), Physician and Patient global assessment, extra muscular disease activity, health assessment questionnaire (Indian version), and muscle pain using visual analogue scores will be measured at baseline and after 12 weeks.

Eligible participants idiopathic inflammatory myositis (IIM) satisfying the inclusion and exclusion criteria  will be randomised in to exercise snack group and standard care group.

Exercise snack group (ESG) will receive exercise snacks in addition to the standard care, whereas the standard care group (SCG) include will receive only standard care.

After the randomisation process, those assigned to ESG group (intervention) will be taught the required exercise by the investigator.  Each exercise session will consist of a brief warm up and a bout of body weight-based exercise. Repeated training sessions will be conducted once in 4 weeks (i.e. at 0, 4 and 8 weeks) for each of the patients in the intervention group till they complete 12 weeks. The exercise consists of: Warm-Up*i.e.,*basic mobility exercises for 1minute. Main exercises include skipping without rope, standing bicycle crunches and chair squat jumps. The patient will be required to do these exercises a minimum of 3 times a day for 3 days/week to a maximum of 3 times a day for 5 days/week. Standard of care will be continued in both the groups. Patients will be instructed to maintain the level of physical activity at the same level as prior to initiation of the study and will be assessed using the international physical activity questionnaire.

To ensure compliance, each patient will be contacted telephonically and the frequency, duration of exercises done every week will be recorded. Diaries and a customised checklist will be supplied to patients where they can mark the events(exercise sessions) performed every week. The diaries/checklists will be reviewed at the end of 4 weeks, 8 weeks, and at 12 weeks (part of regular visits). Each visit for availing regular medications will be utilised to ensure compliance (by showing videos). Only those individuals who will perform at least 9 sessions of exercise per week will be considered as compliant.

**1.**VO2max will be measured by cardiopulmonary exercise testing in both the groups at baseline i.e., at the time of randomisation and at the end of 12 weeks. VO2 max test will be performed on an ergometer bicycle starting at 30–40W, and the required power output will be increased by 10W every minute. VO2 max will be determined by incremental cycling to exhaustion. Pulmonary minute ventilation and gas exchange (O2 uptake and CO2 output, respectively) would be measured breath by breath. The VO2 max will be calculated using Astrand (unconditioned) protocol which is based on a linear relationship between mechanical load, oxygen uptake and heart rate (HR) obtained during the test.

2. Venous blood samples (after overnight fasting) will be collected from participants in both groups (exercise and SCG) at baseline and 12 weeks  for testing the lipid profile (total cholesterol, low density lipoproteins, high density lipoproteins and triglycerides); Fasting blood glucose and serum Insulin will be measured and insulin resistance will be calculated using Homeostatic Model Assessment for Insulin Resistance (HOMA IR) 2 model using online tool.

3.The fat and lean body mass will be assessed using dual-energy X-ray absorptiometry (DXA) at baseline and after 12 weeks for participants in both groups.