244 Training & Testing Cadence-Power-Relationship during Decisive Mountain Ascents at the Tour de France Authors S. Vogt1, K. Roecker1, Y. O. Schumacher 1, T. Pottgiesser 1, H.-H. Dickhuth1, A. Schmid 1, L. Heinrich 2 Affiliations 1 Department of Preventive and Rehabilitative Sports Medicine, University of Freiburg, Freiburg, Germany 2 Fachbereich Sportmedizin, Institut für Angewandte Trainingswissenschaft, Leipzig, Germany Key words Abstract 0.6 W/kg) with a mean cadence of 73 ± 6 rpm l" SRM powermeter ! and a mean duration of 37:41 ± 16:16 min. l" pedaling rate The aim of the study was to report the relation- Power output averaged 294 ± 36 W (4.3 ± 0.6 W/ l" professional cycling ship between cadence and power developed by kg) at a mean cadence of 70 ± 6 rpm during l" Grand Tours professional cyclists during high mountain as- 57:40 ± 10:32 min on HC climbs. The maximal cents of the Tour de France. From the 10 cyclists mean power for long durations (1800 s) showed (30 ± 4 years, 178 ± 8 cm, 69 ± 6 kg) involved in a mean power output of 327 W and 346 W for the study, 108 ascents were recorded and ana- the 1st and HC climbs, respectively. The evalua- lyzed using a mobile power measurement device tion of the cadence-power output and the dis- (SRM Training Systems, Jülich, Germany). Based tance per pedaling cycle-power output relation- on topographic characteristics, the ascents were ship shows that high power outputs are mainly categorized into 1st and Hors Category (HC) yielded by higher pedaling cadences and higher climbs. During the ascents of the 1st Category gears. climbs, power output averaged 312 ± 43 W (4.5 ± Introduction output produced by “successful” and “lesser suc- ! cessful” cyclists on different types of mountain The Tour de France is the most famous and pres- ascents. tigious cycling stage race in the world. A broad Therefore, the purpose of this study was to illus- range of skills is required to be successful in this trate direct power output in relation to cadence race. The overall classification of the Tour de of professional cyclists during high mountain as- France is primarily determined by successfully cents of the Tour de France using direct power performing in the individual time trials and on output measurements. accepted after revision the ascents of the mountain passes in the Alps February 16, 2007 and Pyrenees. Although heart rate (HR) monitor- ing has been used to estimate exercise intensity Methods Bibliography ! DOI 10.1055/s-2007-965353 in Grand Tours [7,13,14,24,26], direct quantifica- Published online Sept. 13, 2007 tion of power output during hill climbing is un- Subjects Int J Sports Med 2008; 29: known. In recent years, the development of light- The participating cyclists (n = 10) were members 244–250 © Georg Thieme weight portable devices measuring direct power of professional cycling teams and perform a total Verlag KG Stuttgart • New York • ISSN 0172-4622 output on the bicycle has shed new light on the training and competition workload ranging from instantaneous evaluation of performance during 30 000 to 35000 km per year. Their mean (± SD) Correspondence cycling competition [6,20,27,30,32]. age, height and body mass were 30 ± 4 years, Dr. Stefan Vogt, MD Department of Preventive and Many studies have addressed the concept of opti- 178 ± 8 cm and 69 ± 6 kg, respectively. The weight Rehabilitative Sports Medicine mal cadence [1,3,4,11,12,15,17,19,22,25], how- of the bikes used, including 2 water bottles University of Freiburg ever, only preliminary data exist describing the (500 ml) and bottlecages, was approximately Hugstetter Strasse 55 79106 Freiburg cadence used by professional cyclists when cy- 7.4 –8.2 kg. To calculate the relative power out- Germany cling uphill [7,15,23,24,26]. Until now, the ca- put the bicycle mass has not been taken into ac- Phone: + 497612707455 dence-power relationship of these decisive mo- count. The athletes gave their written informed Fax:+497612707470 stefan.vogt@uniklinik- ments of a cycling race is unknown. Furthermore, consent to participate in the study, which was freiburg.de no attempt has been made to describe the power approved by the scientific committee of our de- Vogt S et al. Performance Profile during… Int J Sports Med 2008; 29: 244 –250 Training & Testing 245 partment. The studied riders were not contending for a high averaged over each complete pedal revolution and multiplied by overall ranking (40–150 on General Classification; 40–120th the cadence to calculate the power output. place for most stages) but represented a broad range of skills The slope for each SRM crank powermeter was calculated dy- from mountain specialists (required to perform maximally in namically at the SRM laboratory. Because of a possible drift of mountain stages) to team domestiques (required to work for the zero offset frequency, the device was zeroed daily by one of the team in the majority of stages, but usually not required to the investigators prior to each stage. After each stage, the data perform maximally in mountain stages). was transmitted from the registration unit to a personal com- puter for further processing. SRM measurements A total of 108 recordings of mountain ascents of 10 professional Methodical limitations cyclists at the 2005 Tour de France were specifically selected. Re- It is well known that despite calibration, SRM cranks might show cordings of ascents, where the riders were within 9% of the stage a variation larger than 2.5% during prolonged use. As no stan- winning time on that day, were referred to as “climber” files dardized static or dynamic calibration was performed prior to (n = 47) and were required to perform maximally during the as- the investigated race, it cannot be excluded that this issue might cents. Recordings of riders over 9% to the winning time were influence the present data set. However, Gardner et al. [9] dem- marked as “helpers” (n = 61). The helpers usually work for the onstrated that once adjusted, the calibration of SRM cranks is team in the majority of the stages, but do not have to perform stable throughout an 11-month racing season. The SRM systems maximally during the ascents. used in this study underwent calibration by the manufacturer The terminology of the mountain categories used by the race or- before regular use during racing. Furthermore, a potential drift ganizers was adopted. Mountain ascents were classified based in zero offset during the race through, e.g., temperature changes on the following criteria: the climbs are divided into categories or different altitudes can occur and might have influenced the from 1 (most difficult) to 4 (least difficult) based on their diffi- data as well, as zero offset was checked before, but not after the culty, measured as a function of their gradient and altitude dif- race. It can be speculated that a potential zero offset drift would ference. A fifth category, called Hors Category (outside category), occur in both directions, causing in some cases false higher or is represented by mountains even more difficult than those of lower power readings. In average, these errors would contribute the 1st Category (1st). Climbs of the 1st Category had a differ- to a slightly larger variability in the data, but probably not signif- ence in altitude of at least 600 m, with an average gradient of icantly influence the averages displayed in this study. Neverthe- > 6.5% or with an altitude difference > 800 m. HC climbs had at less, these methodical limitations have to be considered when least an altitude difference of 1500 m or an average gradient of interpreting the data. > 7.5% at an altitude difference of > 850 m. For the purpose of the study, only mountain ascents of the 1st and HC were selected Race characteristics representing the most famous mountain passes of the Alps (e.g., The study took place during the “2005 Tour de France”, an inter- Col de la Madeleine, Col du Telegraphe, Col du Galibier) and the national stage race for elite cyclists. This 21-day stage race cov- Pyrenees (e.g., Col d’Aubisque, Col de Peyresourde). ered 3698 km in 18 mass start stages (7 flat stages, 5 semi- The recordings of these 10 riders were analyzed using a mobile mountainous stages, 6 mountain stages), 2 individual time trials power measurement device (SRM road version Professional, and one team time trial. The overall winner covered this distance SRM Training Systems, Schoberer Rad Messtechnik, Jülich, Ger- in 86 h 15 min at an average speed of 41.65 km/h. many). The accuracy of these systems has been tested and vali- During the mountain stages (stages 9, 10, 11,14, 15, 16), the riders dated [9] and used in many other scientific studies [6,20,30,31]. had to overcome 10 climbs of the 1st and 5 climbs of the HC. The SRM system registers continuously power output (W) and cadence (rpm). The SRM system is a crank-based device that Race data analyses measures the mechanical power output to the bike through mul- The PC stored competition data were processed with the soft- tiplication of the torque applied to the cranks and the speed at ware provided with the SRM System. Raw data analysis was con- which they turn. The crankset experiences a tiny deformation ducted using a specially designed software program (JMP soft- when torque is applied. The SRM system measures this deforma- ware; SAS Institute, Cary, NC, USA) to determine overall averages tion using strain gauges attached to components inside the for power output, cadence and speed during the different moun- crank.