Physiological assessment of isolated running does not directly replicate running capacity after triathlon-specific cycling

Abstract

Triathlon running is affected by prior cycling and power output during triathlon cycling is variable in nature. We compared constant and triathlon-specific variable power cycling and their effect on subsequent submaximal running physiology. Nine well-trained male triathletes (age 24.6 ± 4.6 years, 4.5 ± 0.4 L · min⁻¹; mean ± SD) performed a submaximal incremental run test, under three conditions: no prior exercise and after a 1 h cycling trial at 65% of maximal aerobic power with either a constant or a variable power profile. The variable power protocol involved multiple 10–90 s intermittent efforts at 40–140% maximal aerobic power. During cycling, pulmonary ventilation (22%, ±14%; mean; ±90% confidence limits), blood lactate (179%, ±48%) and rating of perceived exertion (7.3%, ±10.2%) were all substantially higher during variable than during constant power cycling. At the start of the run, blood lactate was 64%, ±61% higher after variable compared to constant power cycling, which decreased running velocity at 4 mM lactate threshold by 0.6, ±0.9 km · h⁻¹. Physiological responses to incremental running are negatively affected by prior cycling and, to a greater extent, by variable compared to even-paced cycling. Testing and training of triathletes should account foe higher physiological cost of triathlon-specific cycling and its effect on subsequent running.

Keywords:

• variable power
• cycle-run
• stochastic cycling

Acknowledgements

The authors would like to thank all the participants for their time and efforts, the staff members in British Triathlon Federation and the English Institute of Sport in Loughborough, United Kingdom for supporting this project, and especially Jill Stanley for her support in the laboratory.