Sprint interval training in hypoxia stimulates glycolytic enzyme activity

Med Sci Sports Exerc. 2013 Nov;45(11):2166-74. doi: 10.1249/MSS.0b013e31829734ae.

Abstract

Purpose: In this study, we compared the effect of sprint interval training (SIT) in normoxia versus hypoxia on muscle glycolytic and oxidative capacity, monocarboxylate transporter content, and endurance exercise performance.

Methods: Healthy male volunteers (18-30 yr) performed 6 wk of SIT on a cycling ergometer (30-s sprints vs 4.5-min rest intervals; 3 d · wk(-1)) in either normobaric hypoxia (HYP, FiO2 = 14.4%, n = 10) or normoxia (NOR, FiO2 = 20.9%, n = 9). The control group did not train (CON, n = 10). Training load was increased from four sprints per session in week 1 to nine sprints in week 6. Before and after SIT, subjects performed a maximal incremental exercise test plus a 10-min simulated time trial on a cycle ergometer in both normoxia (MAX nor and TT nor) and hypoxia (MAX hyp and TT hyp). A needle biopsy was taken from musculus vastus lateralis at rest 5-6 d after the last exercise session.

Results: SIT increased muscle phosphofructokinase activity more in HYP (+59%, P < 0.05) than that in NOR (+17%), whereas citrate synthase activity was similar between groups. Compared with the pretest, power outputs corresponding to 4 mmol blood lactate in HYP during MAX nor (+7%) and MAX hyp (+9%) were slightly increased (P < 0.05), whereas values were constant in NOR. V·O 2max in MAX nor and TT performance in TT nor and TT hyp were increased by ≈ 6%-8% (P < 0.05) in either group. The training elevated monocarboxylate transporter 1 protein content by ≈ 70% (P < 0.05). In CON, all measurements were constant throughout the study.

Conclusion: SIT in hypoxia up-regulated muscle phosphofructokinase activity and the anaerobic threshold more than SIT in normoxia but did not enhance endurance exercise performance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anaerobic Threshold
  • Bicycling / physiology
  • Citrate (si)-Synthase / metabolism
  • Exercise Test
  • Glycogen / metabolism
  • Humans
  • Hypoxia / enzymology*
  • Hypoxia / physiopathology
  • Male
  • Monocarboxylic Acid Transporters / metabolism
  • Muscle Proteins / metabolism
  • Oxygen Consumption
  • Phosphofructokinases / metabolism
  • Physical Conditioning, Human / physiology*
  • Physical Endurance / physiology*
  • Quadriceps Muscle / metabolism*
  • Symporters / metabolism
  • Young Adult

Substances

  • Monocarboxylic Acid Transporters
  • Muscle Proteins
  • SLC16A4 protein, human
  • Symporters
  • monocarboxylate transport protein 1
  • Glycogen
  • Citrate (si)-Synthase
  • Phosphofructokinases