Effect of two drafting modalities in cycling on running performance

Purpose: The purposes of this study were first to compare the physiological responses during a triathlon where cycling was performed alternatively wit h another cyclist (alternate draft triathlon, ADT) or continuously behind h im (continuous draft triathlon, CDT), and second to study the incidence of these two drafting modalities in cycling on the subsequent running performa nce done during a simulated triathlon. Methods: Ten male triathletes of nat ional level performed a sprint distance triathlon (0.75-km swim, 20-km bike , 5-km run) on two different sessions, one where the triathlete alternative ly rode in front or at the back of another cyclist and rotating every 500 m , the other where the triathlete drafted continuously a professional cyclis t whose task was to reproduce all split times recorded during the alternate situation. Oxygen uptake ((V) over dot O-2), expiratory flow ((V) over dot E), heart rate (HR) were recorded during the entire bike and run sections and blood lactate concentrations ([La-](b)) were analyzed at the end of eac h event composing the triathlon. Results: The results showed that expirator y flow, oxygen uptake. heart rate and blood lactate concentrations were sig nificantly lower in CDT on the bike compared with drafting in alternation ( 148.1 vs. 167.2 L.min(-1), 49.9 vs. 59.8 mL.min(-1).kg(-1), 154.7 vs. 173.1 beats.min(-1), 3.5 vs. 6.3 mmol.L-1, respectively). The results also revea led that running after biking in CDT (for similar cycling speeds) significa ntly improved the subsequent running speed compared to ADT (17.87 vs. 17.15 km.h(-1)). Furthermore, (V) over dot E. (V) over dot O-2, HR, and [La-](b) were significantly higher during CDT run compared with ADT run (175.6 vs. 170.4 L.min(-1), 69.7 vs. 66.8 mL.min(-1).kg(-1), 182.6 vs. 177.3 beats.min (-1), 9.6 vs. 7.5 mmol.L-1, respectively). Conclusions: These results showe d that drafting continuously behind a lead cyclist allows triathletes to sa ve a significant amount of energy during the bike leg of a sprint triathlon and creates the conditions for an improved running performance compared wi th a situation where cycling is performed alternating the lead with another cyclist.