אימונים High-intensity interval training increases in vivo oxidative capacity with no effect

[Mike Bikov]

Am J Physiol Regul Integr Comp Physiol. 2013 Mar 1;304(5):R333-42. doi: 10.1152/ajpregu.00409.2012. Epub 2012 Dec 19.
High-intensity interval training increases in vivo oxidative capacity with no effect on P(i)→ATP rate in resting human muscle.

Larsen RG, Befroy DE, Kent-Braun JA.
Source
Department of Kinesiology, University of Massachusetts, Amherst, MA 01003, USA.

Abstract
Mitochondrial ATP production is vital for meeting cellular energy demand at rest and during periods of high ATP turnover. We hypothesized that high-intensity interval training (HIT) would increase ATP flux in resting muscle (VPi→ATP) in response to a single bout of exercise, whereas changes in the capacity for oxidative ATP production (Vmax) would require repeated bouts. Eight untrained men (27 ± 4 yr; peak oxygen uptake = 36 ± 4 ml·kg(-1)·min(-1)) performed six sessions of HIT (4-6 × 30-s bouts of all-out cycling with 4-min recovery). After standardized meals and a 10-h fast, VPi→ATP and Vmax of the vastus lateralis muscle were measured using phosphorus magnetic resonance spectroscopy at 4 Tesla. Measurements were obtained at baseline, 15 h after the first training session, and 15 h after completion of the sixth session. VPi→ATP was determined from the unidirectional flux between Pi and ATP, using the saturation transfer technique. The rate of phosphocreatine recovery (kPCr) following a maximal contraction was used to calculate Vmax. While kPCr and Vmax were unchanged after a single session of HIT, completion of six training sessions resulted in a ∼14% increase in muscle oxidative capacity (P ≤ 0.004). In contrast, neither a single nor six training sessions altered VPi→ATP (P = 0.74). This novel analysis of resting and maximal high-energy phosphate kinetics in vivo in response to HIT provides evidence that distinct aspects of human skeletal muscle metabolism respond differently to this type of training.
PMID: 23255590 [PubMed - indexed for MEDLINE] PMCID: PMC3602722 [Available on 2014/3/1]​

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