# Effects of controlled supramaximal high-intensity interval training on muscle capacities and physical functions for older adults: analysis of secondary outcomes from the Umea HIT study-a randomised controlled trial PMID: 39396911 Journal: Age and Ageing Published: 2024-10-13 Authors: Frykholm E, Hedlund M, Becker C, Holmberg H, Johansson B, Klenk J, Lindelöf N, Lindemann U, Simonsson E, Boraxbekk CJ, Rosendahl E ## Question Does group-based controlled supramaximal high-intensity interval training improve muscle capacities and physical function more than moderate-intensity interval training in older adults not engaged in regular exercise? ## Summary In older adults aged 66-79 years who were not regularly exercising, twice-weekly controlled supramaximal cycling intervals for three months produced larger gains in anaerobic cycling performance than a longer moderate-intensity interval program. Muscle capacity and physical function outcomes generally improved within groups, but between-group differences other than anaerobic cycling were not statistically significant. ## Population - Older adults aged 66-79 years, not regularly exercising, recruited by newspaper advertising and medically screened. - Sample size: 68 - Age: Mean 69.7 +/- 3.0 years; range 66-79 years. - Sex: 56% women; 38 women and 30 men. - Fitness level: Not involved in regular exercise; mean peak oxygen uptake 22.9 ml/kg/min. - Health status: 78% had at least one medical diagnosis, 56% hypertension, 69% medication use. ## Methodology - Preplanned secondary outcome analysis from the Umea HIT randomized controlled trial. - Approximately 3 months; 25 twice-weekly sessions. - Group-based training at a local gym on stationary bicycles; outcomes assessed at Umea University Sport Science Lab. - Randomized and controlled study design. ## Protocol - Controlled supramaximal HIT. - Modality: Stationary cycling. - Work intervals: 10 x 6 seconds. - Recovery: 54 seconds between intervals. - Sets or repetitions: 10 intervals. - Intensity: Started at 60% of estimated maximum 6-second mean power output; individualized watt-controlled progression in 4 percentage-point steps. - Session duration: 20 minutes including warm-up and cool-down. - Frequency: Twice weekly. - Program length: Approximately 3 months; 25 sessions. - Progression: First two sessions introductory; standardized individual progression criteria. - Moderate-intensity interval training. - Modality: Stationary cycling. - Work intervals: 3 x 8 minutes. - Recovery: 3 minutes between intervals. - Sets or repetitions: 3 intervals. - Intensity: Started at 40% of maximal aerobic power; individualized watt-controlled progression in 4 percentage-point steps. - Session duration: 40 minutes including warm-up and cool-down. - Frequency: Twice weekly. - Program length: Approximately 3 months; 25 sessions. - Progression: First two sessions introductory; standardized individual progression criteria. ## Outcomes ### Anaerobic cycling performance Status: improved Supramaximal HIT improved more than MIT; within-group changes were 31.3 W for HIT and 12.0 W for MIT. Between-group difference 19.3 W, 95% CI 3.1 to 35.3; ES 0.60. ### Leg power Status: no clear change Both groups improved modestly, but the between-group difference was not significant. Between-group difference 2.4 W, 95% CI -7.9 to 12.5; ES 0.12. ### Hand grip strength Status: no clear change Small improvements were similar between groups. Between-group difference 0.01 N/kg, 95% CI -0.17 to 0.2; ES 0.04. ### Static balance Status: no clear change Both groups improved, with no significant between-group difference. Between-group difference 1.6 seconds, 95% CI -10.4 to 13.7; ES 0.07. ### Dynamic balance Status: no clear change Both groups improved, with no significant between-group difference. Between-group difference -0.8 steps, 95% CI -2.5 to 1.0; ES -0.22. ### Chair stand Status: no clear change Chair stand improved within groups but not significantly more with HIT than MIT. Between-group difference 0.8 repetitions, 95% CI -0.6 to 2.1; ES 0.28. ## Practical Insights - A medically screened, supervised older-adult cycling protocol can use only 60 seconds of hard work inside a 20-minute session. - Short controlled supramaximal intervals may be especially relevant when the target outcome is anaerobic capacity for brief demanding tasks. - For broad physical function outcomes, this protocol should be presented as comparable to MIT rather than clearly superior. - Exact translation to app workouts needs adaptation because the protocol relies on stationary-bike power control and in-person supervision. ## Limitations - Volunteer selection bias is possible. - Sample size was powered for parent-trial primary outcomes, not these secondary outcomes. - No inactive or usual-care control group. - Limited power to detect small between-group differences. - Anaerobic cycling results may be influenced by similarity between training and test modality. ## Safety And Adherence - Exercise session attendance was 88.0% for HIT and 88.1% for MIT. - Across 1497 attended participant-sessions, discomfort was reported 52 times in HIT and 94 times in MIT, mostly musculoskeletal. - None of the discomfort reports were considered serious adverse events by external reviewers. - One exercise discontinuation at participant request was considered related to the intervention due to back pain after handling equipment. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/39396911/) (pubmed) - [DOI](https://doi.org/10.1093/ageing/afae226) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11471315/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.