The Oxidative–Glycolytic Balance Influenced by Sprint Duration Is Key during Repeated Sprint in Hypoxia

Abstract

Purpose: This study investigates the effects of normobaric hypoxia on repeated sprint exercise (RSE) with different balance between oxidative (phosphocreatine and oxidative pathway) and glycolytic contributions. Therefore, performance and psychophysiological responses were compared during RSE to exhaustion with the same exercise-to-rest ratio (1:2) but different sprint durations (5, 10, or 20 s) either in normoxic (RSN) or hypoxic (RSH; FIO 2 = 0.13) conditions. Methods: On separate visits, 10 active participants completed in random order three cycling RSN (5:10; 10:20 and 20:40) and three similar RSH sessions to exhaustion. Vastus lateralis muscle oxygenation was recorded by near-infrared spectroscopy. Blood lactate concentration, limb and breathing discomfort, and ratings of perceived exertion were measured. Results: Total sprint number was smaller in hypoxia than in normoxia for 5:10 (20.8 ± 8.6 vs 14.7 ± 3.4; P = 0.014) and 10:20 (13.7 ± 6.3 vs 8.8 ± 2.5; P = 0.018) but not 20:40 (5.6 ± 1.9 vs 5.6 ± 2.5). The fatigue index was larger in hypoxia only for 5:10 (−43.5%, P < 0.001). Irrespective of condition, blood lactate concentration increased with the sprint duration with higher values for 20:40 than 5:10 (13.1 ± 2.7 vs 11.5 ± 2.2 mmoL•L −1 ; P = 0.027). Limb and breathing discomfort and ratings of perceived exertion did not differ in all RSE. Muscle oxygenation was mainly impacted by sprint duration (i.e., main effect of sprint duration on [HHb] min, [tHb] max, Δ[HHb], and Δ[tHb]) but not by hypoxia. The normoxia-to-hypoxia percentage decrease for total sprint number for 5:10 was correlated with the highest power output over 5 s (R 2 = 0.55; P = 0.013) and 10 s (R 2 = 0.53; P = 0.016). Conclusions: Hypoxia impairs repeated sprint ability when the oxidative but not the glycolytic contribution is substantial. The oxidative-glycolytic balance, influenced partly by sprint duration, is key during repeated sprint in hypoxia.

Muscle Oximetry in Sports Science: An Updated Systematic Review

“…The extent of notable changes in the muscle oxygenation levels measured with NIRS indicators in response to various physiological stressors (hypoxia, exercise intensity, exercise profile, training) was investigated in the following cases: repeated sprint training [ 14 , 15 , 34 , 107 , 157 , 165 , 168 , 172 , 188 , 191 , 192 ], high-intensity interval training [ 15 , 25 , 43 , 137 , 157 , 164 , 184 ], voluntary hypoventilation at low lung volume versus normal breathing [ 17 , 34 , 88 , 89 , 151 ], inspiratory muscle training/pre-activation [ 45 , 97 , 100 , 112 , 113 , 140 , 152 , 181 , 187 ], blood flow restriction [ 12 , 14 , 147 , 149 , 191 , 192 ], intermittent bilateral cuff inflation of lower limbs with three 5/10-min ischemia–reperfusion cycles [ 53 ], hypoxia (normo- and hypo-baric) [ 14 , 35 , 59 , 72 , 76 , 77 , 90 , 108 , 123 , 129 , 130 , 137 , 142 , 148 – 150 , 168 , 188 , 191 , 192 , 200 ], ischem...…”

Repeated sprint training in hypoxia induces specific skeletal muscle adaptations through S100A protein signaling

“…In the present study, three weeks of RSN and RSH training similarly improved RSA, Wingate and time‐trial performance. The previously reported heterogeneity between studies regarding performance is likely due to differences in training modalities, in particular the exercise:recovery ratio, which affects the oxidative‐glycolytic balance during sprint repetitions 46 …”

“…The previously reported heterogeneity between studies regarding performance is likely due to differences in training modalities, in particular the exercise:recovery ratio, which affects the oxidative-glycolytic balance during sprint repetitions. 46 It is not clear if RSH differently alters muscle glycolytic or oxidative adaptations as compared to RSN. 14,15 We here report reduced levels of proteins involved in OXPHOS after both training modalities.…”

Recommendations for Women in Mountain Sports and Hypoxia Training/Conditioning

“…5 ). It is known that hypoxia reduces the power output during RSH at a higher oxidative but not glycolytic contribution [ 225 ]. With more slow-twitch fibres, the oxidative-glycolytic balance that is influenced by sprint duration and the exercise:rest ratio may be different between women and men.…”