Produced, edited, and copyrighted by
Professor Emeritus Brent S. Rushall, San Diego State University
Volume 7, Number 1: October 25, 2004


Speed swimming is one of the most inefficient of all of man's sporting activities. When swimming velocity is increased it occurs with the cost of a huge energy increase. There comes a point in swimming where a swimmer can go no faster because no more energy can be generated. Consequently, the main task of competitive swimming is to distribute energy expenditure as evenly as possible over the racing distance so that total fatigue occurs in concert with finally touching the timing pad at a race's end.

When swimmers go out "fast", it is possible for them to complete one lap at the "fast" speed but with the horrendous cost to be paid back almost immediately, that is, during a race. That strategy might lead to an early lead or fast time, which will be lost as the energy debt (variously termed oxygen debt, oxygen deficit, anaerobic debt, etc.) is recouped by the swimmer going slower than is desirable.

In a purely physics way, to go out fast requires a swimmer to generate sufficient energy to maintain high momentum and overcome increased friction and the three forms of resistance. Friction and surface resistance increase linearly with increases in swimming velocity. Form resistance increases quadratically and it is of greater influence and effect than surface resistance and friction. So that water can escape around and under a swimmer, waves are produced with their cost in energy being cubicly related to change in velocity. That energy cost of wave production is huge. Slowing is the only way for a swimmer to reduce the briefly held excessive energy demands when the "going out fast" strategy is followed.

A swimmer does not have to swim much slower than the velocity of "going out fast" to reach the level of racing economy that matches efficient energy production. Maintaining consistent pacing (consistent racing economy) yields the highest average velocity for a race that exploits the finite energy reserves of an athlete. To maintain a constant pace above anaerobic threshold, race effort will gradually have to be increased. Consequently, any racing strategy for any distance in swimming (even 50-m races) requires judicious energy use.

The importance of pacing is legend, but seems to be ignored with increasing frequency in swimming. Other sports, such as speed skating, have shown pacing to be a critical performance determinant when energy conservation and allocation is important in a competitive performance. Studies have shown that females have to be more exact at the evenness of their pacing (< 1% lap time variations) than men (greater variations in lap times at start and finish to exploit greater anaerobic capacity are tolerable, but the requirement of similar lap-time consistency to females when doing steady-paced work stage of a race is paramount).

The psychological gains from "going out fast" are insufficient to offset the excessive energy costs of exaggerated swimming velocity. Too often at the 2004 Olympic swimming events were races lost by poor understanding of the demands of effective race strategies. It is the swimmer who leads at the end of a race that is of importance, not the swimmer who goes very fast for the first 50 meters and then slows appreciably. It can be asserted that quite a few events were "lost" at these most recent Games because of poor race pacing. That assertion is justifiable because the phenomenon of pacing correctly is evidenced-based.

Return to Table of Contents for Carlile Coaches' Forum.