BODYSUITS IMPROVE PERFORMANCE OR DO THEY?

Chatard, J.-C., & Wilson, B. (2008). Effect of fastskin suits on performance, drag, and energy cost of swimming. Medicine & Science in Sports & Exercise, 40, 1149-1154.

This study investigated the effects of fastskin bodysuits on 25 and 800 m performances, drag, and energy cost of swimming. Competitive swimmers (M = 10; F = 4) of varying standards and ages served as subjects. Ss swam six distances (25, 50, 100, 200, 400, and 800 m) in a 25 m pool wearing all three forms of swim suit over two weeks. Adequate rest between swims was provided. Ss wore three suits full body to ankles, waist to ankles, and a normal suit. Ss were not shaved in the normal condition. The suits were of various brands (Speedo, Arena, Tyr, ASCI, and Nike) made of Lycra or elastane. Apart from swimming in a pool, swimming flume measures for prone gliding to indicate passive drag were taken. A four-minute flume swim was also performed at 90% of best 1500 m velocity to determine the energy cost in each form of the suits. Lactate and rating of perceived exertion were also measured after each flume swim.

The performance gains of this study were in direct contrast to studies reported in the literature. One has to conclude that in terms of performance, the scientific reports are equivocal.

Two Ss complained about the tightness of the full bodysuits. Among 84 swims, 63 were faster in the full bodysuit than in the lower-body suit. Although actual numbers were not reported, approximately 20% of full and lower-body suit swims were worse than in the normal suit condition. Of those poorer swims, approximately two-thirds were in the lower-body suit. In a statistical sense, that is a significant proportion within the data set of this study and yet it is ignored.

The amount of drag reduction in this study also exceeded that of other published investigations. Unfortunately, the authors revert to theoretical premises to justify the opinion "the 6% reduction in total drag found in the present study and associated with a 3.5% reduction in time performance was not surprising". [Throughout the discussion, the authors also ignore the non-significant differences between the full and lower-body suits and consistently advocate the full bodysuit as being the best. That subjectivity/bias is unacceptable in science.]

In theoretical terms, data gathered from gliding and flume swimming should not be directly generalized to pool swimming, which is the overall theme of the paper. However, the authors do accede to this and other shortcomings in this difficult study topic with regard to passive drag by reporting that it is "more related to gliding aptitude than active swimming". While warning of technique interference through using one form of active drag measures (the MAD system) the authors do not recognize that flume swimming alters the technique, energy cost, and perceptions of swimming. Those alterations also should provoke caution when discussing free pool swimming.

Perhaps the most relevant datum in the study is buried in one of the tables and not discussed. It reports a published study that shows the energy reduction in swimming in a shaved body condition is twice the reduction reported in this paper for either experimental suit than in a traditional suit while unshaved. Despite the reported benefits of these experimental suits, those benefits are only in reference to unshaved conventional suit swimming. It is possible that these suits are not as beneficial as shaved swimming because no published study using fastskin suits approaches the energy cost benefits of swimming with body hair shaved.

The study's implication that any fastskin suit produces beneficial performance improvements (but here it was really only approximately four out of five swims) is in dispute with the claims of individual manufacturers, all of whom claim their products to be better than those of the others.

[A final factor that is not addressed in the study is the psychological placebo effect. Swimmers are largely "brainwashed" to believe that they cannot swim fast unless they are shaved. With the advent of fastskin bodysuits, there is a growing belief that fast swimming is possible whether shaved or unshaved because they remove the mechanical advantage of hair removal. Thus, when measuring performances, most swimmers would expect to perform worse in an unshaven conventional suit condition than when wearing a "fast" fastskin suit. Until that negative self-fulfilling prophecy for performance can be removed from control conditions in fastskin studies, the findings, and in particular those that report benefits, will have to be treated very cautiously.]

Implication. As other studies have shown in full or part, fastskin full and lower-body suits provide drag, energy cost, and performance benefits over unshaven conventional suit swimming in certain circumstances. The claim of benefits is equivocal when compared to other published researches. One should not assume that those benefits equal or exceed the benefits of swimming shaved.

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