Running Economy During the Last Leg of ITU Duathlon Race Simulation in a Laboratory Setting

saac Lee: Running Economy During the Last Leg of a ITU Duathlon Race Simulation in a Laboratory Setting (Under the direction of Bonita Marks) This retrospective study examined running economy (RE) as measured by oxygen uptake (VO2) for 7 highly trained male multi-sport athletes during a laboratory duathlon simulation (running + cycling). Methods: Trial 1 = speed-only single-bout run VO2max test; Trial 3 =10 km run + 30 km cycling at 95-98% of ventilatory threshold followed by a speed- only single-bout run VO2max test. RE was represented by VO2 obtained at 5, 7, and 10 mph during the VO2max tests during Trials 1 and 3. Results: A significant interaction effect (p = 0.047) occurred for Trial * Intensity (3 x 2 repeated measures ANOVA; Factor 1 = exercise intensities [speeds 5, 7, 10 mph]; Factor 2 = VO2max for Trials 1 and 3). Post hoc paired samples t-tests approached significance for 7 and 10 mph (p = 0.054; p = 0.064, respectively). Conclusion: RE is affected in a laboratory duathlon simulation during moderate intensity running.

iv ACKNOWLEDGEMENTS I would first like to thank God who gives me strength and has always stayed close to me. I would also like to thank my lovely family for their unbelievable support throughout my academic endeavor. Without their support I would not have made it this far. I would also like to thank my committee advisor, Dr. Bonita Marks, and members of my committee, Dr. Claudio Battaglini and Dr. Edgar Shields, who all gave me a tremendous amount of support and encouragement along the way. I want to thank the many friends in my native Korea who have given me their thoughts and prayers of support and encouragement every step of the way. Lastly, I would like to add these words from Bible that I live by: “I can do everything through Him who gives me strength.” (Philippians 4:13)

v TABLE OF CONTENTS LIST OF TABLES....................................................................................................................vii LIST OF FIGURES...............................................................................................................viii DEFINITIONS OF TERMS AND ABBREVIATIONS......................................................ix CHAPTER I. INTRODUCTION…………… ..…………………………………… ….……...1 Statement of Purpose……………………………………………………… …………3 Research Question and Hypothesis……………………………… ..………… ..……..3 Limitations……..………………………………………………………… ………….4 Delimitations………………………………………………………………………… .4 Assumptions……………………………………………………………… ………….5 Significance……………………………………………………………… ………….5 II. REVIEW OF LITERATURE………………………………… ..…………….6 Maximal Oxygen Consumption ..................................................................................6 Running Economy………………… ............................................................................8 Measurement of Running Economy............................................................................9 Calculation of Running Economy………… .......................................................10 Running Economy and Endurance Performance.........................................................10 Performance Interventions……...................................................................................11

vi III. METHODOLOGY..........................................................................................12 Subjects.......................................................................................................................12 Instrumentation...........................................................................................................13 General Procedures.....................................................................................................13 Trial 1…………………………………………………………………………… ......14 Trial 3…………………………………………………………………………… ......15 Research Design and Statistical Analyses………………………………………… ...16 IV. RESULTS………………………………………………………………… ....18 Descriptive Information………………………………………………………… .…18 Repeated Measures ANOVA Analysis…………………………………………… ....20 V. DISCUSSION…............................................................................................24 Study Limitations……………………………………………………………2 6 VI. CONCLUSION………………… ... ...…........................................................27 Summary………………………………………………………………… .….27 Conclusion …………………………………………………………………..2 7 Practical Application………………………………………………… .……...28 REFERENCES…………………………………………………………………………… ...29

vii LIST OF TABLES Table 1: ANOVA Analysis……………………………………………………… ..……….…20 Table 2: Confidence intervals for Intensity……………………………………… ...………..20 Table 3: Confidence intervals for Trial……………………………………………………… 21 Table 4: Confidence intervals for interaction (Intensity * Trial)………………… ……….….21 Table 5: Paired Samples Statistics……………………………………………… .………..…21 Table 6: Running Economy (VO2) for each Intensity Category (Speed) for Trial 1 vs. Trial 3…………………………………………………………………………… ..23

viii LIST OF FIGURES Figure 1: Mean Distribution (n = 7) VO2 max (ml/kg/min) for Trial 1....................................19 Figure 2: Mean distribution (n = 7) VO2 max (ml/kg/min) for Trial 3…………………… ….19 Figure 3: The plot of the marginal means for intensity by trial………… ..……………… ......22

ix DEFINITION OF TERMS AND ABBREVIATIONS  Euhydration: Normal daily body water content, measured by urine specific gravity (USg). Normal USg values range from 1.010 to 1.030.  International Triathlon Union (ITU) Duathlon: A 10 km run, 40 km cycling time trial and 5 km run performed in immediate and successive order.  Maximal Oxygen Uptake (VO2max): The maximal amount of oxygen that can be utilized during exercise, measured in milliliters of oxygen consumed per minute per kilogram of body weight (ml/kg/min).  Submaximal Oxygen Uptake (VO2submax): An estimation of VO2max during submaximal exercise testing.  Maximal Treadmill Protocol Test: An exercise test which provides incremental increases in intensity up to maximum capacity for aerobic exercise. In this study we used a cycle ergometer and treadmill protocol for the test, which was done in the lab.  Running Economy (RE): A measure of the energy demand of running at a set submaximal speed. Runners with good RE use less energy and less oxygen than runners with poor RE, which is reflected in a lower level of oxygen uptake at any given speed.  Speed-Only VO2max (SOVO2max): a protocol for measuring VO2max using incremental increases in speed while maintaining a constant grade of 0%.  Ventilatory Threshold (VT): The point at which pulmonary ventilation increases relative to oxygen consumption during aerobic exertion. This usually occurs at ≥50 %VO2max, and is dependent on the subject’s aerobic conditioning status.

1 CHAPTER I INTRODUCTION The duathlon, a run-bike-run competition, is a time honored multi-sport event dating back to the early 1970s. At that time duathlons, initially termed biathlons, were popular as informal local competitions which in subsequent decades led to more formalized and structured competitions sponsored by large corporations (ITU, 2012). In the 1980s duathlons experienced a surge in popularity, but this resurgence was later overshadowed by the sport of triathlon, which included swimming along with running and biking and attracted larger numbers of competitors (ITU, 2012). Today the duathlon remains a popular sport although it is still not officially recognized by the International Olympic Committee. In the United States, the recognized governing body for the duathlon is USA Triathlon, whose duties include certifying duathlons and setting rules for competition. International duathlon events are governed by the International Triathlon Union (ITU), which also certifies races and set rules for competition on a global level (ITU, 2012). Duathlons typically consist of run-bike-run competitions of various lengths, but the ITU established length of a duathlon consists of a 10 kilometer (km) running event followed by a 40 km cycling event and ending with a 5 km run (ITU, 2012). There are typically periods, referred to as transitions, between each running and cycling phase in which athletes exchange running shoes for bikes and helmets, and vice-versa. Transitions have energy costs of their own and have been shown to affect overall race performance and race time (Millet and Vleck, 2000). An athlete’s ability to successfully perform in these events is dependent on a wide array of factors, which include physiological factors (age, gender, diet, general state of health

2 and previous conditioning), psychological factors, geographic factors (altitude, weather conditions during the event) and the physical characteristics of the race route itself (Saunders et al., 2004). As in any sports event, athletes and coaches involved in duathlons everywhere are concerned with the age-old question of how to maximize an athlete’s performance to confer an advantage over that of the competition. To that end, various physiological measures and performance tests have been adapted in an effort to develop and perfect training methodologies. One of the most important of these metrics includes testing for maximal oxygen uptake (VO2max), which represents the maximal capacity to utilize oxygen during exercise, and is typically done on a treadmill. The results of the VO2max test reflect an athlete’s level of cardiopulmonary fitness and can be used not only to design exercise training programs and to prescribe the level of training intensity, but also to monitor training load, so as not to overly stress an athlete beyond his or her capabilities (Balady et al. 2010). Running economy (RE), which can be thought of as one measure of optimal running performance, is a metric which has been defined in many different terms. The simplest definition of RE is the most descriptive: RE is the oxygen uptake (VO2) at submaximal intensities. Runners with good running economy are those who have lower oxygen uptake at any given speed (Davies et al., 1997). In other words, they are able to utilize oxygen more efficiently during sustained long distance running. Running economy has been demonstrated to be a better metric than VO2max for predicting performance in elite long distance runners who have comparable capacities for oxygen uptake (Saunders et al. 2004). In spite of this, RE has been less well studied than other factors in the field of running performance (Foster and Lucia, 2007). To date, there have been relatively few studies investigating the compounding effects of a multi-sport competition on running performance. One of these, a master’s thesis by

than other factors in the field of running performance (Foster and Lucia, 2007). To date, there have been relatively few studies investigating the compounding effects of a multi-sport competition on running performance. One of these, a master’s thesis by

The study investigates the effects of a duathlon simulation on running economy.