Performance and drag during drafting swimming in highly trained triathletes

Abstract

Purpose: The influence of drafting was studied on the swimming performance, metabolic response, and passive drag of eight triathletes. Methods: The performance in drafting position was measured directly behind another swimmer during a 400-m swim and compared with the nondrafting position. Metabolic response concerned V̇O2, blood lactate, stroke rate, stroke length, and rating of perceived exertion. Drag was measured by passive towing. Results: In drafting position, the triathletes swam on average faster (3.2%) over the 400-m swim than in nondrafting position (4 min, 47.69 ± 10.35 s vs 4 min, 57.25 ± 7.24 s; P < 0.01). Blood lactate and stroke rate were significantly lower (9.6 mM vs 10.8 mM; 39.9 cycle · min-1 vs 41.3 cycle · min-1 P < 0.02) and stroke length higher (2.10 m · cycle-1 vs 1.97 m · cycle-1, P < 0.01) than in nondrafting position. V̇O2 and rating of perceived exertion were not statistically different. Passive drag was lower in drafting than in nondrafting position (P < 0.01). However, the gain in drag decreased with the towed velocity (from 26% at 1. l m · s-1 to 13% at 1.7 m · s-1). In drafting position, the performance gain was related to the 400-m time (r = 0.80, P < 0.01) and to the skinfold thickness (r = 0.94, P < 0.01), with faster and leaner swimmers having greater gains of performance. Conclusions: Swimming behind another swimmer in a race is advantageous for triathletes.