How the Swim Affects Triathlon Performance

The ability to perform well during a triathlon is dictated by one’s ability to perform optimally in each of its three disciplines: swimming, biking, and running. Previous research has demonstrated that running performance during a triathlon is affected by cycling intensity, cadence, bicycle frame geometry, power output consistency, and drafting. However, very little research, if any, has looked at the relative contributory effect of swimming on overall performance in a triathlon. As such, Peeling & Landers conducted a review of the literature pertaining to Swimming intensity during triathlon that was recently published in the Journal of Sports Sciences.

The authors of this review cited previously conducted research by Vleck, Laurse, Kreider, Delextrat, McCole, Bentley, Chatard, themselves, and several others. Based on this review, the current state of the literature can be summarized as follows:
​

• The best overall race performers were faster in the first few hundred meters (~ 200 to 500m) of the swim and slower swimmers generally expend more energy during the bike leg in order to “catch up” to those who exited first. These have correlated to overall performance and demonstrate the importance of being in the first pack of cyclists.
• Swim intensities of 80-85% and 90-95% have enabled athletes to cycle at greater power outputs than 100% swim intensities during sprint-distance triathlon. However, those who swim at 80-85% intensity also run 1% quicker than those who swim at 100% intensity.  Therefore, in consideration of the point noted above, an athlete’s swimming ability must enable them to swim with the front pack while simultaneously staying within 80-90% of maximum effort.
• Drafting during the swim (in order to minimize frontal resistance) certainly contributes to minimizing one’s intensity at a given speed as it has been shown to lower athletes’ heart rates and blood lactate concentrations. Further, with respect to the cycling leg, drafting during the swim has been shown to correlate with higher cycling efficiency as well as mean and peak power output. Thus, in order to minimize the physiological demands of swimming, one must swim 0-50 cm behind the toes or 500-100 cm lateral and behind the hands of the athlete he or she is drafting off of. This in turn, may allow one to maintain ideal positioning within the front pack with minimal effort.
• Wetsuits are intended to increase buoyancy and therefore decrease both hydrodynamic and passive resistance during the swim. These have been shown to improve swim time with relatively less energy cost (stroke rate, oxygen consumption and blood lactate accumulation), therefore saving energy that may be utilized in later portions of the race. It should be noted that wetsuits have also been found to increase body and skin temperature and therefore, may induce heat stress in an athlete.
• Speedsuits, on the other hand, decrease frictional resistance between the athlete’s skin and the water and do so with minimal effect on body temperature. These have been shown to improve swim time without affecting stroke rate, stroke length, and blood lactate accumulation. Therefore, speedsuits should be utilized at temperatures greater than 25 degrees (Celcius) or when wetsuits are not permitted.

​It was no secret that the various strategies mentioned above are utilized during the swim leg of a triathlon in order to increase the likelihood of a optimal results. However, Peeling & Landers were perhaps the first to document all variables through this review in its entirety. It should be noted, however, that the majority of research has solely focused on the Sprint and Olympic distances and therefore, the recommendations pertaining to long course races (70.3 and Ironman) may differ.