Performance and physiological responses during a sprint interval training session: Relationships with muscle oxygenation and pulmonary oxygen uptake kinetics

Abstract

The purpose of this study was to examine the cardiorespiratory and muscle oxygenation responses to a sprint interval training (SIT) session, and to assess their relationships with maximal pulmonary O 2 uptake (VO 2pmax), on- and off-VO 2p kinetics and muscle reoxygenation rate (Reoxy rate). Ten male cyclists performed two 6-min moderate-intensity exercises (≈90-95% of lactate threshold power output, Mod), followed 10 min later by a SIT session consisting of 6 × 30-s all out cycling sprints interspersed with 2 min of passive recovery. VO 2p kinetics at Mod onset (VO 2p τon) and cessation (VO 2p τ off) were calculated. Cardiorespiratory variables, blood lactate ([La] b) and muscle oxygenation level of the vastus lateralis (tissue oxygenation index, TOI) were recorded during SIT. Percentage of the decline in power output (%Dec), time spent above 90% of VO 2p max (t > 90% VO 2p max) and Reoxy rate after each sprint were also recorded. Despite a low mean VO 2p (48.0 ± 4.1% of VO 2p max), SIT performance was associated with high peak VO 2p (90.4 ± 2.8% of VO 2p max), muscle deoxygenation (sprint ΔTOI = -27%) and [La] b (15.3 ± 0.7 mmol l -1) levels. Muscle deoxygenation and Reoxy rate increased throughout sprint repetitions (P < 0.001 for both). Except for t > 90% VO 2p max versus VO 2p τ off [r = 0.68 (90% CL, 0.20; 0.90); P = 0.03], there were no significant correlations between any index of aerobic function and either SIT performance or physiological responses [e.g., %Dec vs. VO 2p τ off: r = -0.41 (-0.78; 0.18); P = 0.24]. Present results show that SIT elicits a greater muscle O 2 extraction with successive sprint repetitions, despite the decrease in external power production (%Dec = 21%). Further, our findings obtained in a small and homogenous group indicate that performance and physiological responses to SIT are only slightly influenced by aerobic fitness level in this population. © 2011 Springer-Verlag.