Repeated Double-Poling Sprint Training in Hypoxia by Competitive Cross-country Skiers.

• Autores: Raphaël Faiss, Grégoire Millet, Sarah J. Willis, Dennis-Peter Born, Billy Sperlich, Jean-marc Vesin, Hans-Christer Holmberg
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 47, Nº. 4, 2015, págs. 809-817
• Idioma: inglés
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• Resumen

  • AB Purpose: Repeated-sprint training in hypoxia (RSH) was recently shown to improve repeated-sprint ability (RSA) in cycling. This phenomenon is likely to reflect fiber type-dependent, compensatory vasodilation, and therefore, our hypothesis was that RSH is even more beneficial for activities involving upper body muscles, such as double poling during cross-country skiing. Methods: In a double-blinded fashion, 17 competitive cross-country skiers performed six sessions of repeated sprints (each consisting of four sets of five 10-s sprints, with 20-s intervals of recovery) either in normoxia (RSN, 300 m; FiO2, 20.9%; n = 8) or normobaric hypoxia (RSH, 3000 m; FiO2, 13.8 %; n = 9). Before (pre) and after (post) training, performance was evaluated with an RSA test (10-s all-out sprints-20-s recovery, until peak power output declined by 30%) and a simulated team sprint (team sprint, 3 x 3-min all-out with 3-min rest) on a double-poling ergometer. Triceps brachii oxygenation was measured by near-infrared spectroscopy. Results: From pretraining to posttraining, peak power output in the RSA was increased (P < 0.01) to the same extent (29% +/- 13% vs 26% +/- 18%, nonsignificant) in RSH and in RSN whereas the number of sprints performed was enhanced in RSH (10.9 +/- 5.2 vs 17.1 +/- 6.8, P < 0.01) but not in RSN (11.6 +/- 5.3 vs 11.7 +/- 4.3, nonsignificant). In addition, the amplitude in total hemoglobin variations during sprints throughout RSA rose more in RSH (P < 0.01). Similarly, the average power output during all team sprints improved by 11% +/- 9% in RSH and 15% +/- 7% in RSN. Conclusions: Our findings reveal greater improvement in the performance of repeated double-poling sprints, together with larger variations in the perfusion of upper body muscles in RSH compared with those in RSN