Original articles   

The Journal of Sports Medicine and Physical Fitness 2000 June;40(2):103-9

Copyright © 2002 EDIZIONI MINERVA MEDICA

language: English

Physiological profile and predictors of cycling performance in ultra-endurance triathletes

Whyte G., Lumley S., George K. *, Gates P. **, Sharma S. **, Prasad K. **, Mckenna W. J. **

From the Division of Sport Studies University of Wolverhampton * Department of Sports Sciences Manchester Metropolitan University ** Department of Cardiological Sciences St. George’s Hospital Medical School

Background. To ­report phys­io­log­i­cal pro­files, and inves­ti­gate the rela­tion­ship ­between select­ed phys­io­log­i­cal var­i­ables and ­cycling per­for­mance in ­ultra-endu­rance tri­ath­letes.
Methods. Participants: ten ­male (­mean±SD, age; 32±5 ­years) ­ultra-endu­rance tri­ath­letes par­tic­i­pat­ed in the ­study. Physiological pro­files ­were com­pared ­with 10 ­male age-­matched con­trol sub­jects.
Measures: left ven­tric­u­lar struc­ture (­wall thick­ness [LVPWd], inter­nal diam­e­ter [LVIDd], and ­mass [LVM]) and func­tion (dia­stol­ic fill­ing, frac­tion­al short­en­ing, and ­stroke vol­ume [SV]) ­were ­assessed ­using stan­dard M-Mode, 2D, and Doppler echo-­car­di­og­ra­phy. Maximal and sub-max­i­mal exer­cise gas ­exchange respons­es ­were meas­ured on-­line dur­ing a max­i­mal ramp­ing ­cycle-ergom­e­ter exer­cise ­test.
Results. Ultra-endu­rance tri­ath­letes dem­on­strat­ed sig­nif­i­cant­ly larg­er LVPWd, LVIDd, LVM, SV, V.O2 max, anaer­o­bic thresh­old (AT), and pow­er to ­body-­mass ­ratio com­pared ­with con­trols. Cycling per­for­mance for ­both Ironman and ­half Ironman ­were sig­nif­i­cant­ly cor­re­lat­ed ­with LVPWd, LVM, and SV. LVIDd was sig­nif­i­cant­ly cor­re­lat­ed Ironman ­cycle ­time ­alone. Oxygen con­sump­tion (V.O2) at AT, per­cent­age of V.O2 max at AT, and ­peak pow­er to body­mass ­ratio ­were sig­nif­i­cant­ly cor­re­lat­ed to ­bike fin­ish ­time in the ­half Ironman, but not Ironman.
Conclusions. The cor­re­la­tion ­between ­cycling per­for­mance, LVM and SV sug­gests ­that the ­more con­di­tioned ath­letes may be bet­ter ­able to main­tain a ­high car­diac out­put dur­ing pro­longed ­cycling. Sub-max­i­mal gas ­exchange respons­es are pre­dic­tors of ­cycling per­for­mance for the ­half-Ironman but not the Ironman. These ­results sug­gest ­that oth­er fac­tors includ­ing the long­er dura­tion ­swim ­prior to the ­cycling com­po­nent, may ­impact ­upon ­cycle per­for­mance.