The Determination of Total Energy Expenditure During and Following Repeated High-Intensity Intermittent Sprint Work

Matt Laurent, Advisor The literature addressing the glycolytic contribution to overall energy expenditure has primary been utilized during resistance training and cycling. There is a paucity of data examining the glycolytic contribution to overall energy expenditure (EE) in the form of highintensity intermittent sprint work. Therefore, the purpose of this study was to examine the variation in oxidative and glycolytic contribution during two HIIT protocols using a 1:1 work-to-rest ratio and a 2:1 work-to-rest ratio. Seventeen physically active participants performed three exercise testing sessions. The first session involved an incremental maximal exertion treadmill test along with a sprint familiarization. Sessions two and three involved a 30:30 and 30:15 HIIT protocol performed in a counterbalanced order. The HIIT sessions involved four sets, of four sprints with three minutes of recovery between each set. During both HIIT sessions, oxygen consumption accumulation, carbon dioxide production, and respiratory exchange ratio were measured to calculate overall oxidative and EPOC contribution. Blood lactate concentration was measured to calculate overall glycolytic contribution. Total EE was determined by summating oxidative, glycolytic and EPOC measurements. Relative contribution of energy system involvement was analyzed using a 2 x 4 repeated measures ANOVA. Paired t-test determined significant differences in total EE between sessions. Comparing total session EE, independent t-test revealed no significant difference between HIIT sessions (p = .947). There was a significant difference between the two sessions with respect to overall kCal expenditure from the oxidative system (p = .037), glycolytic system (p < 0.01), and EPOC (p <0.01). Independent t-test revealed a significant difference in glycolytic (p < 0.01), oxidative (p < 0.01), and EPOC contribution (p < 0.01) between both HIIT sessions. Repeated-measures ANOVA revealed a significant difference between sets and the two iv HIIT sessions in regards to the oxidative (p = .047) and glycolytic (p = .022) contribution, and a significant difference between relative contribution from oxidative (p < 0.01) and glycolytic system (p < 0.01) between sets. In conclusion, utilizing pulmonary gas exchange to represent the oxidative and EPOC in conjunction with blood lactate to represent the overall glycolytic contribution depicts an acceptable EE estimation during a bout of HIIT. v ACKNOWLEDGMENTS I want to thank Dr. Matt Laurent for his support, constructive criticism, and commitment. His continuous guidance throughout this process has prepared me to become a better researcher and engrained traits in me to become a successful writer. Thank you for guiding me through this process and installing qualities that will stick with me throughout my career. I would also like to thank Dr. Adam Fullenkamp and Dr. Matt Kutz for being part of my thesis committee and providing feedback throughout this process. I would like to thank Kaitlyn Kielsmeier for her eagerness and determination throughout this process. Her lively persona made participants feel at ease when coming into the lab and set a positive vibe for the data collection. I would also like to thank Stephanie Douglas for taking the time out of her busy schedule to assist us with our data collection. Stephanie’s calm composure and eagerness to help and learn made this process efficient. We developed strong cohesion and worked well as a team. I wish them the best of luck with their future endeavors. I would lastly like to thank my family and girlfriend for believing in my abilities to complete my thesis. They all have motivated me to achieve whatever I set out to accomplish. When times were challenge throughout this process, I knew I always had a shoulder to lean on. Thank you for all your inspiration and love.