EFFECT OF 3/7 STRENGTH TRAINING METHOD IN CARDIAC REHABILITATION: A RANDOMIZED CONTROL TRIAL

A. Gillet^1,2,3, M. Lamotte¹, K. Forton¹, C. Dewachter³, F. Macera³, A. Roussoulieres³, G. Deboeck², P. van de Borne³

¹Erasme University Hospital, Université Libre de Bruxelles, Physiotherapy, Brussels, Belgium, ²Université Libre de Bruxelles, Rehabilitation, Brussels, Belgium, ³Erasme University Hospital, Université Libre de Bruxelles, Cardiology, Brussels, Belgium

Background: Cardiovascular rehabilitation (CR) with physiotherapist is a type 1A intervention for cardiovascular disease. Among the various exercise modalities, strength training (ST) is a recommended for improving cardiorespiratory fitness (volume of oxygen consumption [VO₂] peak.However, different modalities of ST can coexist and which modalities should be preferred is still a matter of discussion. A ST method called 3/7 allows greater strength gains with a shorter training time with healthy young subject. However, the feasibility, the safety and its effects have never been studied in CR.

Purpose: The aim was to assess the feasibility, safety and efficacity of improving VO₂ peak of the 3/7 method in CR.

Methods: In this single center randomized clinical trial, participants underwent 12 weeks of supervised training. A total of 101 participants with cardiovascular disease aged 34 to 85 years were enrolled.
Intervention: Group 3/7 consisting of 5 incremental sets of 3 to 7 repetitions with 15 s of inter-set intervals of ST on leg press; leg extension, leg curl, triceps press machine. Group 3X9 (usual care) of 3 sets of 9 repetitions with 1 min of inter set intervals on the same machine and at the same intensity (70% of 1RM). Patients completed 3 sessions per week; endurance training is the same in both groups.
The primary outcome was change in VO₂ peak during the cardiopulmonary exercise test from baseline to 12 weeks. Secondary outcomes were isokinetic leg strength at 60°/sec and feasibility.

Results: 101 randomized participants, 60 (87%) were male, the mean (SD) age was 62 (8) years, and 49 were randomized to 3/7 and 52 to 3X9. A total of 65 participants completed testing at 12 weeks for the primary outcome, including 32 in the 3/7 group and 33 in the 3X9 group. There were similar improvements from baseline between groups, VO₂ peak by 19% in 3/7 group with 17% in the 3X9 group (mean [SD] oxygen uptake: 3/7, 3.6 [4.1] mL/kg/min; 3X9, 3.3 [4.5] mL/kg/min; P = .4). 3/7 improved quadriceps strength by 12% compared with 11% in the 3X9 group (mean [SD] isokinetic leg strength: 3/7, 23 [21] N/m; 3X9, 10 [22] N/m; P = .01). We had more dropouts in the usual care group compared to the 3/7 group (22 vs 14). 3/7 group had high feasibility scores and low rates of withdrawal due to serious adverse events (1). Most dropouts were due to other conditions (Lost of follow-up [n=11], COVID-19 [n=6], other medical problems [n=6], returns to work [n=5], withdrew [n=4]).

Conclusions: In this randomized clinical trial, a 12-week ST of the 3/7 method coupled with endurance training improved VO₂ peak to the same level as the usual care in cardiac rehabilitation but 3/7 improved more leg strength. The 3/7 method may reduce the number of dropouts compared because the time training is reduced for the same volume of work.

Implications: These findings support inclusion of 3/7 method in cardiac rehabilitation programs as an adjunct or alternative modality to usual care by physiotherapists.

Funding acknowledgements: A.G. received grants form Fonds Erasme

Keywords:
Cardiac Rehabilitation
Strength training
Cardiovasular Diseaese

Topics:
Cardiorespiratory
Musculoskeletal
Community based rehabilitation

Did this work require ethics approval? Yes

Institution: Erasme University Hospital, Université Libre de Bruxelles, Brssels, Belgium

Committee: Ethics Committee Erasme Hospital

Ethics number: B4062020000176