For submaximal steady state workloads leading to exhaustion between one and some tens of minutes, some authors (Sassi et al., 1999; Sassi et al, submitted) suggested the possibility to estimate the time to exhaustion (TEEST) using a regression equation which includes lactate parameters collected at min 5 and min 10 of a submaximal constant workload, with a root mean square error in cross validation of 13.2 %. The aim of this study was to use this approach to estimate the individual power versus time to exhaustion (W-TEEST) relationships in cyclists of different performance levels. The resulting W-TEEST relationships were compared with the actual mechanical power output data recorded during their training. Methods Data was collected on 8 cyclists (VO2max 69.2 ± 15.4 ml·kg-1·min-1; weight 69.5 ± 11.0 kg; height 179 ± 9 cm; age 33 ± 9 yrs; body fat 6,0±4,9): 3 professional cyclists (PC), 2 mountain bikers (MB), and 3 recreational cyclists (RC). The individual W-TEEST relationship was estimated by submitting each subject, in the same day with a minimum of 90 min of recovery, to 2 or 3 submaximal workloads (5 min at 100 watt, followed by increases of 25 watt·30 sec-1 until the target workload, which was then maintained for 10 min). Based on our previous experiences, for the description of the W-TEEST relationship, workloads were selected in order to obtain 2 TEEST values ranging between 10 min and 60 min for each subject. A third trial was performed When the first 2 TEEST values showed a difference lower than 25 min. Professional cyclists and mountain bikers performed the tests during their competition period. The W-TEEST relationships were obtained by fitting the individual TEEST values according to the logarithmic equation: W = b · ln(TE) + a. The data of the five subjects was also compared with their training mechanical power output files. Results As subjects had a large range in % body fat, all the parameters were normalised for lean body mass (LBM). Individual W-TEEST relationships are shown in fig.1. The maximal aerobic power (MAP, i.e. the maximal power that can be sustained for about 60 min) extrapolated by the W-TEEST equations (MAPEST), was highly correlated to the subject`s VO2max·kgLBM-1 (r = 0.95; p<0.001). The average value of b (characterising the downward slope of the W vs. TEEST relationship) was -0.716±0.180, and its correlation with Vo2max·kgLBM-1 was r = 0.67. Cyclists approached their W-TEEST regression line only during fractions of high intensity training sessions, and in few occasions 3 of them slightly overcame (10-20 W) the W-TEEST but only during uphill cycling. Discussion/Conclusion The high correlation found between VO2max·kgLBM-1 and MAPEST supports the usefulness of the W-TEEST method for cyclists` endurance capacity evaluation. The moderate correlation between b and VO2max·kgLBM-1, means that the downward slope of the W vs. TE is only partially related to the VO2max of the subjects (r2=0.45). The individual gap between the anaerobic threshold (i.e. the maximal power that can be sustained for one hour) and the MAP underlines the need to individualise the power output training prescription in this submaximal range (above the anaerobic threshold and below the MAP). The W-TEEST relationship seems to offer insight to this aim. The W-TEEST relationships in the PCs were in agreement with the ones presented in the literature concerning workouts lasting 30-60 min (Lucia et al., 2001). In conclusion, this W-TEEST approach could have practical usefulness both for endurance capacity evaluation and for submaximal training power output prescription in cyclists. Further systematic validations are required.
© Copyright 2004 Book of Abstracts - 9th Annual Congress European College of Sport Science, July 3-6, 2004, Clermont-Ferrand, France. Veröffentlicht von UFR STAPS Clermont-Ferrand II, Faculte de Medecine Clermont-Ferrand I. Alle Rechte vorbehalten.