Central and peripheral muscle fatigue following repeated‐sprint running in moderate and severe hypoxia

Nathan Townsend (1, 2) , Franck Brocherie (3) , Grégoire P Millet (4) , Olivier Girard (1, 5)

1 ASPETAR Research and Education Centre
2 HBKU - Hamad Bin Khalifa University
3 SEP (EA7370) - French Institute of Sport (INSEP), Laboratory Sport, Expertise and Performance (EA7370)
4 ISSUL - Institute of Sport Sciences of University of Lausanne
5 UWA - The University of Western Australia

We examined the effects of increasing hypoxia severity on repeated-sprint running performance and neuromuscular fatigue. Thirteen active males completed eight sprints of 5 s (recovery = 25 s) on a motorized sprint treadmill in normoxia (sea level, SL; F I,O 2 = 0.21), in moderate hypoxia (MH; F I,O 2 = 0.17) and in severe hypoxia (SH; F I,O 2 = 0.13). After 6 min of passive recovery, in all conditions a second set of four sprints of 5 s was conducted in normoxia. Neuromuscular function of the knee extensors was assessed at baseline (Pre-) and 1 min after set 1 (Post-set 1) and set 2 (Post-set 2). In set 1, the mean distance covered in SL (22.9 ± 1.2 m) was not different to MH (22.7 ± 1.3 m; P = 0.71) but was greater than in SH (22.3 ± 1.3 m; P = 0.04). No significant differences between conditions for mean distance occurred in set 2. There was a decrease in maximal voluntary contraction torque (Δ = −31.4 ± 18.0 N m, P < 0.001) and voluntary activation (%VA; Δ = −7.1 ± 5.1%, P = 0.001) from Pre-to Post-set 1, but there was no effect of hypoxia. No further change from Post-set 1 to Post-set 2 occurred for either maximal voluntary contraction or %VA. The decrease in potentiated twitch torque in SL (Δ = −13.3 ± 5.2 N m) was not different to MH (Δ = −13.3 ± 6.3 N m) but was lower than in SH (Δ = −16.1 ± 4 N m) from Pre-to Post-set 1 (interaction, P < 0.003). Increasing severity of normobaric hypoxia, up to an equivalent elevation of 3600 m, can increase indices of peripheral fatigue but does not impact central fatigue after 'all-out' repeated-sprint running.

Mots clés: repeated-sprint running; central fatigue; hypoxia; peripheral muscle fatigue

Domaines: Sciences du Vivant [q-bio]; Physiologie du sport

Nathan Townsend, Franck Brocherie, Grégoire P Millet, Olivier Girard. Central and peripheral muscle fatigue following repeated‐sprint running in moderate and severe hypoxia. Experimental Physiology, 2021, 106 (1), pp.126-138. ⟨10.1113/EP088485⟩. ⟨hal-04067314⟩