Studies of swimmers have shown that drafting reduces the metabolic cost of swimming by between 11-38%. One study of swimmers (Bassett et al, 1991) conducted over 450 metres at 95% of maximum speed found that drafting reduced oxygen consumption by 8%, blood lactate by 33%, and perceived exertion by 21%. Factors such as swimming speed, body shape, direction of the current, water viscosity, distance between and relative position of the swimmers, will all alter the magnitude of the advantage.
Perhaps open water swimming’s greatest asset is that it is much more interesting than swimming in a pool. There are so many variables in an open water race that can influence the result, especially in ocean swims. A competitor’s ability to select an advantageous position at the start, to choose the best route through the shore break, to spot a rip and take advantage of it, to keep calm in a pack, to draft effectively, to use the direction of the prevailing current to time a ‘surge’, to round a buoy efficiently, and to ride a wave into shore -- all of these require knowledge that might allow an astute competitor to outperform a faster swimmer. Good open water coaches try to impart this knowledge to their charges.
It is hypocritical, on the one hand, to laud a swimmer for being clever enough to utilise a rip, yet on the other hand describe someone who has utilised a draft as “dishonest”, “disrespectful”, or “bludging on someone else’s efforts”. Both tactics are ‘part of the game’; neither are cheating.
Part of the problem is a misconception that, if a person drafts off a competitor, the lead swimmer has to work harder than if swimming solo. The erroneous rationale behind this is that the lead swimmer effectively has to tow those drafting like a truck and its trailers.
In fact, drafting works by utilising the reduced drag forces encountered when swimming in the leader’s slipstream. The disruption of these drag forces by the leader occurs irrespective of whether anyone is drafting behind them, so the energy cost to the lead swimmer is no greater than if the leader was swimming solo.
Ocean swimming should be playing a greater role in developing Australia’s young open water swimmers. The huge number of exciting ocean races scheduled each summer ought to provide an opportunity for young distance swimmers to practice their open water skills, and to receive rewards for the countless hours of hard training needed to be a distance swimmer. But if this is to develop further, Australian ocean swimming has to conform to the open water rules and codes of conduct that are accepted world-wide, and that includes acceptance of drafting as a part of the sport.
Ken Thorley
