Repeated sprint training under hypoxia improves aerobic performance and repeated sprint ability by enhancing muscle deoxygenation and markers of angiogenesis in rugby sevens

Eur J Appl Physiol. 2022 Mar;122(3):611-622. doi: 10.1007/s00421-021-04861-8. Epub 2022 Jan 3.

Abstract

Objective: To evaluate the effects of repeated sprint (RS) training in hypoxia on aerobic performance, repeated sprint ability (RSA), and muscle oxygenation in Rugby Sevens.

Methods: Fourteen Rugby Sevens players were randomly allocated into hypoxic (RSH, FIO2 = 14.5%, n = 7) or normoxic (RSN, FIO2 = 20.9%, n = 7) groups. Both groups underwent RS training consisting of 3 sets of 6-s × 10 sprints at 140% of velocity at peak oxygen uptake ([Formula: see text]) on a motorized treadmill, 3 days/week for 6 weeks in addition to usual training. Hematological variables, hypoxia-inducible factor-1 alpha (HIF-1α), and vascular endothelial growth factor (VEGF) concentrations were measured. Aerobic performance, RSA, and muscle oxygenation during the running-based anaerobic sprint (RAS) test were analyzed.

Results: RSH caused no changes in hemoglobin concentration and hematocrit but significant improvements in [Formula: see text] (7.5%, p = 0.03, ES = 1.07), time to exhaustion (17.6%, p = 0.05, ES = 0.92), and fatigue index (FI, - 12.3%, p = 0.01, ES = 1.39) during the RSA test compared to baseline but not RSN. While ∆deoxygenated hemoglobin was significantly increased both after RSH and RSN (p < 0.05), ∆tissue saturation index (- 56.1%, p = 0.01, ES = 1.35) and ∆oxygenated hemoglobin (- 54.7%, p = 0.04, ES = 0.97) were significantly decreased after RSH. These changes were concomitant with increased levels of HIF-1α and VEGF in serum after RSH with a strong negative correlation between ∆FI and ∆deoxygenated hemoglobin after RSH (r = - 0.81, p = 0.03).

Conclusion: There was minimal benefit from adding RSH to standard Rugby Sevens training, in eliciting improvements in aerobic performance and resistance to fatigue, possibly by enhanced muscle deoxygenation and increased serum HIF-1α and VEGF concentrations.

Keywords: Altitude training; Hypoxic-inducible factor-1 alpha; Near-infrared spectroscopy; Team sports; Vascular endothelial growth factor.

MeSH terms

  • Athletic Performance / physiology*
  • Biomarkers / blood
  • Humans
  • Hypoxia
  • Hypoxia-Inducible Factor 1, alpha Subunit / blood
  • Male
  • Muscle, Skeletal / metabolism*
  • Oxygen Consumption / physiology*
  • Physical Conditioning, Human
  • Rugby / physiology*
  • Running / physiology*
  • Thailand
  • Vascular Endothelial Growth Factor A / blood
  • Young Adult

Substances

  • Biomarkers
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Vascular Endothelial Growth Factor A