Efeitos do exercício físico aeróbio e de força na anatomia cardíaca = Treino de força NÃO prejudica. Efeitos do treino aeróbio regressam com o destreino.

A prospective randomised longitudinal MRI study of left ventricular adaptation to endurance and resistance exercise training in humans

http://jp.physoc.org/content/early/2011/10/03/jphysiol.2011.217125.abstract?papetoc

Published online before printOctober 3, 2011, doi:10.1113/jphysiol.2011.217125The Journal of Physiology,

  1. Angela L Spence1
  2. Louise H Naylor1
  3. Howard H Carter1,
  4. Christopher L Buck1
  5. Lawrence Dembo2
  6. Conor P Murray2
  7. Philip Watson2,
  8. David Oxborough3
  9. Keith P George4 and 
  10. Daniel J Green1,5

Abstract

The principle that ‘concentric’ cardiac hypertrophy occurs in response to strength training, whilst ‘eccentric’ hypertrophy results from endurance exercise, has been a fundamental tenet of exercise science. This notion is largely based on cross-sectional comparisons of athletes using echocardiography. In this study, young (27.4±5.5yrs) untrained subjects were randomly assigned to supervised, intensive, endurance (END n=10) or resistance (RES, n=13) exercise and cardiac MRI scans and myocardial speckle tracking echocardiography were performed at baseline, after 6-months of training and a subsequent 6-weeks of detraining. Aerobic fitness increased significantly in END (3.5 to 3.8 L.min-1, P<0.05) but was unchanged in RES. Muscular strength significantly improved compared to baseline in both RES and END (Δ=53.0±4.2 versus 36.4±4.5 kg, both P<0.001) as did lean body mass (2.3±0.4 kg, P<0.001 versus 1.4±0.6 kg P<0.05). MRI derived left ventricular (LV) mass increased significantly following END (112.5±7.3 to 121.8±6.6g, P<0.01) but not RES, whilst training increased end-diastolic volume (ΔLVEDV, END: +9.0±5.0 versus RES +3.1±3.6 mL, P=0.05). Interventricular wall thickness significantly increased with training in END (1.06±0.0 to 1.14±0.06, P<0.05) but not RES. Longitudinal strain and strain rates did not change following exercise training. Detraining reduced aerobic fitness, LV mass and wall thickness in END (P<0.05), whereas LVEDV remained elevated. This study is the first to use MRI to assess LV adaptation in response to intensive supervised endurance and resistance training. Our findings provide some support for the ‘Morganroth hypothesis’, as it pertains to LV remodelling in response to endurance training, but cast some doubt over the proposal that remodelling occurs in response to resistance training.

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