AUTHOR=Paquette Myriam , Bieuzen François , Billaut François 

TITLE=Sustained Muscle Deoxygenation vs. Sustained High VO2 During High-Intensity Interval Training in Sprint Canoe-Kayak

JOURNAL=Frontiers in Sports and Active Living

VOLUME=1

YEAR=2019

URL=https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2019.00006

DOI=10.3389/fspor.2019.00006

ISSN=2624-9367

ABSTRACT=<p>Recent data suggests that peripheral adaptations, i.e., the muscle ability to extract and use oxygen, may be a stronger predictor of canoe-kayak sprint performance compared to VO<sub>2</sub>max or central adaptations. If maximizing the time near VO<sub>2</sub>max during high-intensity interval training (HIIT) sessions is believed to optimize central adaptations, maximizing the time near maximal levels of muscle desaturation could represent a critical stimulus to optimize peripheral adaptations.</p><p><bold>Purpose:</bold> Therefore, the purpose of this study was to assess the VO<sub>2</sub>, muscle oxygenation and cardiac output responses to various HIIT sessions, and to determine which type of HIIT elicits the lowest muscle oxygenation and the longest cumulated time at low muscle O<sub>2</sub> saturation.</p><p><bold>Methods:</bold> Thirteen well-trained canoe-kayak athletes performed an incremental test to determine VO<sub>2</sub>max and peak power output (PPO), and 4 HIIT sessions (HIIT-15: 40x[15 s at 115%PPO, 15 s at 30%PPO]; HIIT-30: 20x[30 s at 115%PPO, 30 s at 30%PPO]; HIIT-60: 6x[1 min at 130%PPO, 3 min rest]; sprint interval training (SIT): 6x[30 s all-out, 3 min 30 rest]) on a canoe or kayak ergometer. Portable near-infrared spectroscopy monitors were placed on the <italic>Latissimus dorsi</italic> (LD), <italic>Biceps brachii</italic> (BB), and <italic>Vastus lateralis</italic> (VL) during every session to assess changes in muscle O<sub>2</sub> saturation (SmO<sub>2</sub>, % of physiological range).</p><p><bold>Results:</bold> HIIT-15 and HIIT-30 elicited a longer time &gt;90%VO<sub>2</sub>max (HIIT-15: 8.1 ± 6.2 min, HIIT-30: 6.8 ± 4.6 min), compared to SIT (1.7 ± 1.3 min, <italic>p</italic> = 0.006 and <italic>p</italic> = 0.035) but not HIIT-60 (4.1 ± 1.7 min). SIT and HIIT-60 elicited the lowest SmO<sub>2</sub> in the VL (SIT: 0 ± 1%, HIIT-60: 8 ± 9%) compared to HIIT-15 (26 ± 12%, <italic>p</italic> &lt; 0.001 and <italic>p</italic> = 0.007) and HIIT-30 (25 ± 12%, <italic>p</italic> &lt; 0.001 and <italic>p</italic> = 0.030). SIT produced the longest time at &gt;90% of maximal deoxygenation in all 3 muscles, with effect sizes ranging from small to very large.</p><p><bold>Conclusions:</bold> Short HIIT performed on a canoe/kayak ergometer elicits the longest time near VO<sub>2</sub>max, potentially conducive to VO<sub>2</sub>max improvements, but SIT is needed in order to maximize muscle deoxygenation during training, which would potentially conduct to greater peripheral adaptations.</p>