Edith Cowan University Research Online ECU Publications Pre. 2011 1-1-2010 Examining Pacing Profiles in Elite emaleF Road Cyclists using Exposure Variation Analysis Chris Abbiss Edith Cowan University, [email protected] Leon Straker Marc Quod David Martin Paul Laursen Edith Cowan University Follow this and additional works at: https://ro.ecu.edu.au/ecuworks Part of the Sports Sciences Commons 10.1136/bjsm.2008.047787 This is an Author's Accepted Manuscript of: Abbiss, C. , Straker, L., Quod, M., Martin, D., & Laursen, P. B. (2010). Examining pacing profiles in elite emalef road cyclists using exposure variation analysis. British Journal of Sports Medicine, 44(6), 437–442. Available here This Journal Article is posted at Research Online. https://ro.ecu.edu.au/ecuworks/6377 Downloaded from bjsm.bmj.com on July 7, 2011 - Published by group.bmj.com Original article Examining pacing profiles in elite female road cyclists using exposure variation analysis C R Abbiss,1 L Straker,2 M J Quod,3 D T Martin,3 P B Laursen1 1 School of Exercise, ABSTRACT through the use of discrete Fourier transformation Biomedical and Health 3 Sciences, Edith Cowan Objective In this study, the amplitude and time that dominant power frequency bands may exist, 23 University, Joondalup, distribution of power output in a variety of competitive which may be cycling task specific. However, in Western Australia, Australia cycling events through the use of a new mathematical these studies, the use of Fourier transformation 2School of Physiotherapy, analysis was examined: exposure variation analysis (EVA). only quantifies the degree of variation and is not Curtin University of Design Descriptive field study. sensitive to changes in amplitude, frequency and Technology, Bentley, Western Australia, Australia Setting Various professional road cycling events, time. 3Department of Physiology, including; a 5-day–eight-stage tour race, a 1-day World Exposure variation analysis (EVA) is an analy- Australian Institute of Sport, Cup event and the Australian National Individual Time Trial tical method developed to quantify acute and Canberra, Australian Capital Championships. cumulative physical load exposure in ergonomic Territory, Australia Participants 9 elite female cyclists (mean (SD), research.4 For example, Straker et al4 have recently Correspondence to mass = 57.8 (3.4) kg, height = 167.3 (2.8) cm, used EVA to examine musculoskeletal stress in 21 21 Chris R Abbiss, School of Vo2peak = 63.2 (5.2) ml kg min ). children during various administrative tasks and Exercise, Biomedical and Interventions None. found that both posture and muscle activity were Health Sciences, Edith Cowan less variable/more monotonous when working University, 100 Joondalup Main outcome measurements The variation in power Dr, Joondalup, WA 6027, output and the quantification of the total time and acute with computers, compared with books, pens and Australia; time spent at various exercise intensities during paper. Briefly, EVA is an analytical technique that [email protected] competitive professional cycling were examined. describes the total duration as well as the inter- Predefined levels of exercise intensity that elicited first mittent or acute time spent at predefined exercise Accepted 14 May 2008 ventilation threshold, second ventilation threshold and intensities. An advantage of EVA over previously Published Online First used analytical techniques235 is that EVA exam- 3 June 2008 maximal aerobic power were determined from a graded exercise test performed before the events and compared ines not only the cumulative race time spent at . with power output during each event. various exercise intensities (ie, 500 W) but also Results EVA exposed that power output during the time the duration that these exercise intensities were maintained for. It is therefore possible that EVA trial was highly variable (EVASD = 2.81 (0.33)) but more evenly distributed than the circuit/criterium (4.23 (0.31)) may provide a more comprehensive indication of and road race events (4.81 (0.96)). the variation in power output and the work-to-rest Conclusion EVA may be useful for illustrating variations ratios experienced during cycle racing. in the amplitude and time distribution of power output The purposes of this study were to (1) examine during cycling events. The specific race format influenced the amplitude and time distribution of power output of elite-level female road cyclists perform- not only the overall time spent in various power bands, ing in a variety of competitive cycling events but also the acute time spent at these exercise through the use of EVA and (2) examine the intensities. relationship between physiological variables mea- sured during a graded exercise test and field-based elite cycling performance. Ebert et al1 recently documented the percentage of overall performance time spent in various power bands during women’s flat and hilly World Cup METHODS professional races. In this study, it was found that Subjects the racing terrain may have influenced the power Race data were collected from a total of nine elite output profiles in these cyclists, as a greater female cyclists (mean (SD), mass = 57.8 (3.4) kg, percentage of time was spent above 500 W and height = 167.3 (2.8) cm, Vo2peak = 63.2 2 2 between 100 and 300 W during flat and hilly races, (5.2) ml kg 1 min 1) performing in a 5-day–eight- respectively.1 While this analysis provides valuable stage tour race, a 1-day World Cup event and the information regarding the overall power output Australian National Individual Time Trial distribution during such events, comprehensive Championship (described below). Subjects were analysis of the acute time spent in various power classified as ‘‘elite’’ based upon their physiological 6 bands has not been explored. In addition, the characteristics, training status and previous race 78 minor fluctuations in power output often observed performance. Before the events, subjects pro- during cycling are poorly understood. It is believed vided written informed consent in accordance with that these minor fluctuations in power output may the Human Research Ethical Committee of the be related to a central regulation of exercise Australia Sports Commission. intensity.23 However, the fundamental mathema- tical techniques used to quantify variation in these Laboratory data collection studies fail to expose important aspects of varia- Before competing in the events, each subject tion. For instance, it has previously been found performed a graded maximal exercise test on an Br J Sports Med 2010;44:437–442. doi:10.1136/bjsm.2008.047787 437 10_bjsports47787.indd 437 4/26/2010 3:53:21 PM Downloaded from bjsm.bmj.com on July 7, 2011 - Published by group.bmj.com Original article electromagnetically braked cycle ergometer (Lode Excalibur, Data were collected from six cyclists who competed in three Groningen, The Netherlands). The test commenced at a power separate teams. At commencement of the race, ambient air output of 125 W and increased by 25 W every 3 min until temperature was 18uC, relative humidity was 76% and wind volitational exhaustion.8 Respiratory gases were measured speed was 7.6 km h21. throughout the incremental test using a calibrated customised gas analysing system (Australian Institute of Sport, Canberra, Individual road time trial Australian Capital Territory, Australia). Vo2peak was defined as The women’s Australian National Road Time Trial the average of the two highest consecutive 30-s samples. Championship was conducted in Canberra, Australia on 11 Maximal aerobic power (MAP) was calculated in a pro rata March 2001 and involved a 24.2-km individual cycle time trial manner and calculated via the following equation: performed over two flat (,10-m elevation), equal distance laps (12.1 km). Data were collected on six cyclists. Upon commence- + 6 MAP = (WL) [(t/3) 25][9] ment of the event, ambient air temperature was 18uC, relative humidity was 46% and wind speed was 13 km h21. where WL refers to the power output (W) of the last stage completed, and t is the amount of time (min) that was Exposure variation analysis competed in the incomplete workload. The quantification of the total time and acute time spent at The workloads (W) corresponding to the first and second various exercise intensities during all events was expressed using ventilation threshold (VT1 and VT2, respectively) were deter- EVA12 and analysed using customised software written in 10 mined via previously described methods. The calculation of the Labview (National Instruments Corporation, Austin, Texas, power output corresponding to VT1,VT2 and VO2peak (MAP) USA). The EVA program developed for this study expresses allowed the determination of four levels of exercise intensity; power output during the various events as a tridimensional , these include phase I ( VT1), II (VT1 to VT2), III (VT2 to MAP) distribution. In short, EVA was used to separate field-based . 5 and IV ( MAP). A further three levels were determined based cycling power output into both time and amplitude domains. upon the SE of measurement in power output at VT1 (6.9%), As with previous research,15 EVA quantified the percentage of 11 VT2 (4.5%) and MAP (3.0%). These power output ranges were overall race time (ie, cumulative time) that was spent within then compared with power outputs recorded during each field predefined levels of exercise intensity (ie, phase I to phase IV). event (described below). In addition to this, EVA was also used to quantify the duration or length of time for which power output was maintained Field data collection within each predefined level of exercise intensity (ie, acute Before each event, the subject’s bicycle was fitted with a time), without changing to another power band/level. For the professional model SRM power metre (Schoberer Rad purpose of this study, the overall time spent in each power band Mebtechnik, Julich, Germany), which recorded power output, has been referred to as the ‘‘cumulative’’ or percentage of overall cadence and speed every second.