The aim of this study was to determine the effects of drafting behind anoth
er swimmer on the metabolic response and stroke characteristics. Six highly
trained male triathletes performed two maximal 400-m swims, one in a draft
ing (D) and one in a non-drafting condition (ND). Their metabolic response
was assessed by measuring the oxygen uptake ((V) over dotO(2)) and the bloo
d lactate concentration at the end of each 400 m. Swimming velocity, stroke
frequency, stroke length, and stroke index (velocity multiplied by stroke
length) were recorded every 50 m. In the D and ND conditions, there was no
difference in (V) over dotO(2) [66.7 (1.7) ml . kg(-1) . min(-1) vs 65.6 (2
.2) ml . kg(-1) . min(-1), respectively], however, the lactate concentratio
ns were lower in D than in ND [9.6 (0.9) mM vs 10.8 (0.9) mM, respectively,
P < 0.01]. In D, the performance [1.39 (0.02) m . s(-1) vs 1.34 (0.02) m .
s(-1), respectively, P < 0.01] and the stroking parameters (i.e., stroke l
ength and stroke index) increased significantly, while the stroke frequency
remain unchanged. In D, a stable pace was maintained, while in ND, velocit
y decreased significantly throughout the 400 m. In D, the performance gains
were related to the 400-m D velocity (r = 0.78, P < 0.05), and to the body
fat mass (BFM, r = 0.99, P < 0.01). The stroke index in D was also related
to BFM (r = 0.78, P < 0.05). Faster and leaner swimmers achieved greater p
erformance gains and stroke index when drafting. Thus, drafting during swim
ming increases the performance and contributes to the maintenance of stable
stroking parameters such as stroke frequency and stroke length during a 40
0-m swim.