The purpose of this study (Hue at al (1998), European Journal of Applied Physiology, 77, pp. 98-105) was to see if any differences existed in the 10K run immediately following a 40K cycle (Olympic distance triathlon) compared with 10K running alone. A group of male triathletes completed two testing sessions on two different days: (1) 40K of cycling followed by a 10K treadmill run, and (2) a 10K treadmile run at the same speed as (1). Cardiorespiratory data was collected during both runs and stride length and frequency were analysed using videotape. The researchers found that for run (1), the oxygen cost was greater (51.7 ml/kg/min vs 48.3 ml/kg/min), heart rate was higher (175 vs 168) as was ventilation rate (55.8 vs 49 breaths/min). In contrast, the biomechanical variables between the two runs were unchanged.

This suggests that the cycling section prior to the run in a triathlon competition places an extra physiological demand on the run. This could be due to a variety of factors which reduce physiological economy, such as increased lipid metabolism, increased body temperature and dehydration status. However, it would appear that the biomechanics are unchanged, although only stride length and frequency were analysed in this study, and other variables exist that can affect efficiency. For instance, the degree of knee flexion would be an interesting variable to study since this is related to biomechanical economy.

This research supports the practice of combining cycling and running in the same training session as the transition between bike and run seems to alter the physiological stress of running.

Raphael Brandon