ORIGINAL ARTICLES

Circuit weight training and cardiac morphology: a trial with magnetic resonance imaging

M D Camargo¹, R Stein², J P Ribeiro², P R Schvartzman³, M O Rizzatti², B D Schaan¹

¹ Institute of Cardiology of Rio Grande do Sul/FUC (IC/FUC), Porto Alegre, Brazil
² Exercise Pathophysiology Research Laboratory and Cardiology Division, Hospital de Clínicas de Porto Alegre, Brazil
³ Medicina Diagnóstica Mãe de Deus Center, Porto Alegre, RS, Brazil

Beatriz D Schaan, Unidade de Pesquisa do IC/FUC, Av. Princesa Isabel, 370 Santana, 90.620-001 Porto Alegre, RS, Brazil; bschaan.pesquisa{at}cardiologia.org.br

Background: Aerobic training (AT) and circuit weight training (CWT) improve peak oxygen uptake (VO₂PEAK). During CWT the circulatory system is exposed to higher pressure, which could induce left ventricle morphological adaptations, possibly distinct from those derived from aerobic training.

Objective: To compare the effects of aerobic training and CWT upon morphological and functional cardiac adaptations detected by magnetic resonance imaging.

Methods: Twenty healthy sedentary individuals were randomly assigned to participate in a 12-week programme of aerobic training (n = 6), CWR (n = 7) or no intervention (n = 7, controls). Training programmes consisted of 36 sessions, 35 min each, 3 times per week, at 70% of maximal heart rate, and CWT included series of resistance exercises performed at 60% of 1 maximal repetition. Cardiopulmonary exercise testing and cardiac magnetic resonance imaging were performed before and after the intervention.

Results: There was a similar improvement in VO₂PEAK following aerobic training (mean (SD) increment: 12 (4)%) and CWT (12 (4)%), while there was no change in the control group. Aerobic training (12 (6)%) and CWT (16 (5)%) improved strength in the lower limbs, and only CWT resulted in improvement of 13 (4)% in the strength of the upper limbs. However, there were no detectable changes in left ventricular mass, end-diastolic volume, stroke volume or ejection fraction.

Conclusion: In previously sedentary individuals, short-term CWT and aerobic training induce similar improvement in functional capacity without any adaptation in cardiac morphology detectable by cardiac magnetic resonance imaging.

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Commentary on "Circuit weight training and cardiac morphology: a trial with magnetic resonance imaging"

Andrew Maiorana
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