Accepted Article
Received Date : 25-Oct-2013 Revision Requested: 9-Dec-2013 Revised Date : 18-Feb-2014 Accepted Date : 05-Mar-2014 Article type : Regular Paper
High-Intensity Interval Training Alters ATP Pathway Flux During Maximal Muscle Contractions in Humans Ryan G. Larsen1,2 Logan Maynard1 Jane A. Kent-Braun1
Affiliations: 1
Department of Kinesiology, University of Massachusetts, Amherst, MA, USA
2
Department of Health Science and Technology, Aalborg University, Denmark
Running Head: Short-term interval training alters in vivo muscle bioenergetics Correspondence: Ryan Godsk Larsen, Ph.D. Department of Health Science and Technology Aalborg University Fredrik Bajers Vej 7 9220 Aalborg Ø Denmark
[email protected] This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as an 'Accepted Article', doi: 10.1111/apha.12275 This article is protected by copyright. All rights reserved.
Accepted Article
ABSTRACT
Aim: High-intensity interval training (HIT) results in potent metabolic adaptations in skeletal muscle, however little is known about the influence of these adaptations on energetics in vivo. We used magnetic resonance spectroscopy to examine the effects of HIT on ATP synthesis from net PCr breakdown (ATPCK), oxidative phosphorylation (ATPOX) and non-oxidative glycolysis (ATPGLY) in vivo in vastus lateralis during a 24-s maximal voluntary contraction (MVC).
Methods: Eight young men performed 6 sessions of repeated, 30-s “all-out” sprints on a cycle ergometer; measures of muscle energetics were obtained at baseline, and after the first and sixth sessions.
Results: Training increased peak oxygen consumption (35.8±1.4 to 39.3±1.6 ml·min-1·kg-1,
p=0.01) and exercise capacity (217.0±11.0 to 230.5±11.7 W, p=0.04) on the ergometer, with no effects on total ATP production or force-time integral during the MVC. While ATP production by each pathway was unchanged after the first session, 6 sessions increased the relative contribution of ATPOX (from 31±2 to 39±2% of total ATP turnover, p