Physiological predictions of triathlon performance
Date
1990
Authors
Sleivert, Gordon Grant
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Abstract
The purpose of this study was to characterize competitive triathletes and investigate whether selected physiological variables were related to performance in each discipline and overall in a triathlon. Eighteen male and seven female triathletes ( mean body mass= 71.5 ± 2.2 kg, mean height= 176.2 ± 1.7 cm, mean body fat percentage= 16.7 ± 1.4) competed in a short course triathlon ( 1.0 km swim, 30 km cycle and 9 km run) and underwent a battery of physiological tests within a 14 day period. VO2 max, economy of movement and ventilatory theshold (VT) were measured on a cycle ergometer (CE), treadmill ( TM )and tethered swim apparatus (TS). Leg flexion/extension strength was assessed on a Cybex Isokinetic Dynamometer ( 30 degrees* s-1 ).
On the TM both V02 max ( 60.3 ± 1.6 ml* kg-l * min-1 ) and the percentage of V02 max at which VT occurred ( 85.0 ± . 1.1) was greater ( Q < .001) than on the CE ( VO2 max= 57.6 ± 1.5 ml* kg-l * min-1 , VT= 79.6 ± 1.2 % ), and the values on the CE were greater ( Q < .001 )than those measured on the TS ( vo2 max= 46.6 ± 1.6 ml* kg-l * min-1 , VT= 72.8 ± 1.9 % ) . V02 max values in each exercise mode were above values reported for untrained individuals but below values reported for single sport endurance athletes. The specific energy cost of activity (Economy) was found to be 0.15 ± 0.01 ml of 02* kg of body mass- 1 * kg of load-l for swimming, 0.21 ± o.oo ml* w-l for cycling and 0.21 ± o.oo ml* kg-l * m- 1 for running. Absolute/ relative leg extension strength was 191.1 ± 10.4 N·m / 2.62 ± 0.1 N·m * kg-land absolute/ relative leg extension strength was 122.2 ± 6.9 N·m / 1.67 ± 0.1 N·m * kg-l.
Triathlon swim time was best predicted by linear regression of relative swim V02 max and the specific energy cost of swimming ( R2 = 0.72 ). The best predictors of triathlon cycling time were either absolute cycle V02 max or power output at VT on the CE, ( R2 = 0.52 ), and no combination of variables significantly improved prediction of cycling time. Similarly the velocity at running VT was the best predictor of run time ( R2 = 0.79 ). Overall triathlon time was significantly correlated to measures of V02 max and VT in each exercise mode suggesting that specific training in each exercise mode is of importance. The specific energy cost of swimming and running velocity at VT were the best predictors of overall performance ( R2 = 0.90 ). That swimming economy is a strong predictor of overall performance when the swim accounts for only 15 % of total triathlon time suggests a residual effect of swimming on cycling and running performance. A triathlete with a higher velocity at run VT than their competitor should be able to run faster at the same muscle pH, or have a higher muscle pH at the same absolute run velocity. During the later stages of the race this may have a large impact on overall performance.