Anatomical, biomechanical and physiological loading during human endurance performance at selected limb cadences via triathlon GRANT JUSTIN LANDERS BSc (Hons 1A) Department of Human Movement and Exercise Science The University of Western Australia This thesis is presented in fulfilment of the requirements for the degree of Doctor of Philosophy at The University of Western Australia September 2002 Supervisors Professor Brian A. Blanksby Associate Professor Timothy R. Ackland i Dedication I wish to dedicate this thesis to three generations of love and support. Rebecca Elizabeth Landers Who passed away October 2000. She has always given me inspiration to achieve; to keep my eye on the ball. Mum and Dad Yet again for their continual support in all aspects of life, making every opportunity a possibility. Holly Bruse The love of my life; the one who has kept me on track yet create enough distractions, such as a marriage, to ensure my enjoyment. ii Triathlon has had a rapid evolution from its origins 25 years ago in the United States to becoming a full summer Olympic sport in Sydney 2000. It is a sport that combines the three disciplines of swimming, cycling and running linked together with two transitions. It is this combination of events that gives triathlon its uniqueness in the area of exercise science. As a very young sport, the body of knowledge is somewhat limited, but is steadily growing. The following document aims to shed some new light on a range of aspects within the sport of triathlon and highlight triathlon as a sport in its own right with very specific demands when compared with each of the three individual sub-disciplines. iii Acknowledgements With the help of those below, the completion of my PhD has been made not only easy but also a pleasure. I thank all of you for your time, effort and understanding throughout the last three years. Study One Anthropometry of 1997 triathlon world championships To the competitors who gave up their time and participated so willingly. To Bob Eklund for helping me understand factor analysis so that I could decipher the large amounts of data. Again thank you to those who helped with data collection. Study Two Swim significance on race outcome Ron Monson for Mathmatica statistical analysis and commentary. Study Three Cadence during a race (Age group selection race) Renae Landers for her camera skills Holly Bruse for the loan of her camera Mark Batten (Triathlon Western Australia) for allowing the event to be filmed Study Four Cadence during a race (ITU 2000 triathlon world championships) Uniswim for shirts EventsCorp for permitting filming Holly Bruse for her videography skills on camera one from the spa Brett Landers & Scott Beatty for being my helpers on the day and running around like little troopers. Veronica Wilkinson from EventsCorp/Tourism WA for providing the results in excel Stuart Fuller for help in deciphering the female run course Study Five Body size and triathlon running Those from study one and study four who helped again with the collection of data Study Six Unloaded cadence Rob Duffield and Dr Brian Dawson for help with the physiological aspects. Nataphoon Benjanuvatra for his assistance with EMG To the subjects who came and participated without question. iv The Other Special People Technicians; for their untiring support. For always asking plenty of questions and helping me get the most out of each testing session. Darren Smith; who gave me an opportunity to experience elite triathletes first hand and who acted as both an educated scientist and triathlon expert when discussing ideas and possible investigations. Your time has been greatly appreciated. Nat, a fellow swim coach, student and friend who has been available throughout for all sorts of discussions, whether it be pure or social science. Tim Ackland; for his unbiased observation of the thesis and its 'contribution to new knowledge'. To Professor Blanksby. The countless hours that you have devoted to me and this research program over the last four years and the support offered to me during my undergraduate studies has not gone unnoticed. I thank you for your commitment to me and your belief in what I could achieve. Those lengthy discussions where we spread those antlers both within and outside university have opened my eyes to the greater world. The man of so much wisdom, a friend for life. v Preface This thesis contains five studies that sought to systematically use sport science to determine important physical, physiological and biomechanical aspects of triathlon, which could improve classic distance triathlon performance. Study One The initial research continued on from an earlier study in which the author examined the influence of human morphology on triathlon race outcome. As with other endurance and weight bearing sports, low levels of adiposity and measures of proportionality were found to be predictors of triathlon performance. Those with proportionately longer limbs recorded faster total times but no common variance was found between measures of anthropometry and cycle performance during triathlon competition. Study Two Having examined the morphology of triathletes, this study aimed to investigate the relative importance of each of the three sub-disciplines in triathlon. To date, the cycling section has been credited with the greatest impact as it contributes approximately 50% of the total race time. With the legalisation of drafting in classic distance events for elite competitors, the level of significance of each of the three disciplines has altered. It was found that 80% of winners came from the first pack of swimmers to exit the water and that the run discipline exerted the greatest influence on overall finishing position. Study Three No previous research had focused on limb cadences used during a triathlon. Study two had suggested that the run section of a triathlon had the greatest bearing on final race outcome. Therefore, it was considered important to investigate how the run might be improved by altering the cycle mechanics. Thus, study three examined what leg speed was actually used by male and female age-group triathletes during both the ride and run portions of a race, and whether there was any relationship between the two disciplines. Cycle cadence was found to be greater at the end of the cycling leg when compared with vi the start of the cycling section and the run stride rate. The initial cycling cadence was similar to the running stride rate selected by the triathletes during the event. Faster stride rates were found in the first 200 m of the 10 km run, for both male and female competitors. Studies Four & Five This study continued the examination of selected cadences during the cycle and run sections while in competition. The sample in this study included senior elite male and female triathletes competing at the 2000 Triathlon World Championships. Cadence remained consistent through most of the cycling stage but was significantly increased during the final few kilometres for both males and females. The females also pedaled faster during the first 3 km. During the run, stride rate again remained relatively constant and the variation in stride length was related to run and triathlon performance. Male triathletes used a faster cadence and stride rate, and longer strides than the female competitors. During the cycling and running stages, leg frequencies were comparable for both males and females. Study Six This study attempted to integrate the knowledge surrounding body size and shape of triathletes with the stride rate and stride length selection during competition. Previous research had highlighted the importance of lever lengths and low levels of adiposity on performance, and that those who maintained longer strides and faster rates ran faster and performed better. Correlations were conducted between measures of body size (height and mass) with stride rate and stride length. The results from 58 senior elite triathletes (30 female and 28 male) indicated that taller and heavier triathletes used longer strides. Studies Seven & Eight The final study sought to investigate various cycling cadences of triathletes in an attempt to improve the transition from cycle to run phases, and thereby, enhance final triathlon performance. The cycle cadences were presented to triathletes in random order and in an unloaded fashion. Following the laboratory based cadence trials, the vii transitioning run mechanics were then analysed using electromyography and videography. The results indicated a linear increase in the oxygen cost of pedaling with an increase of cadence from 50 to 110 rpm before a significant increase at 130 rpm. Initially, a higher oxygen cost of running was noted in most cases, and there was a sustained increase in the oxygen cost of running following cycling at 130 rpm. Some biomechanical variations were noted in the initial stages of the run but these returned to the normal pattern within 2 minutes of running. viii Publications Scientific Publications Landers, G.J., Blanksby, B.A., Ackland, T.R. and Smith, D. (2000). Morphology and performance of world championship triathletes. Annals of Human Biology, 27(4), 387-400. Ackland, T.R., Blanksby, B.A., Landers, G. and Smith, D. (1998). Anthropometric profiles of elite triathletes. Journal of Science and Medicine in Sport, 1(1), 53-56. Ackland, T., Blanksby, B., Landers, G. and Smith, D. (1998). Anthropometric correlates with performance among world championship triathletes In; Norton K., Olds, T. and Dollman, J. (eds.) Kinanthropometry VI, Proceedings of the Sixth Scientific Conference of the International Society for the Advancement of Kinanthropometry, 1998, 92-104. Landers, G.J. (1998). Kinanthropometry and performance of elite triathletes. Unpublished Honours Thesis, The University of Western Australia. Conference proceedings Landers, G.J., Blanksby, B.A., Ackland, T.R. and Monson, R. (2001). Swim Position and its effect on triathlon outcome. International Triathlon Coaching Symposium, July 23-24 2001, Edmonton, Canada, page 11.