Differences in the energy cost between children and adults during front crawl swimming

There is little information available about the swimming economy of children. The aim of this study was to examine any possible differences in swimming economy in children and adults, swimming front crawl submaximally. Swimming economy was compared in adults [ n=13, aged 21.4 (3.7) years] and children [n=10, aged 11.8 (0.8) years] tested at four submaximal 6-min workloads. Oxygen consumption (VO2) was measured with Douglas bags in a 25-m pool and pacer lights were used to control the velocities. Swimming economy was scaled to body size using mass (BM), body surface area (BSA) and body length (BL). Children had lower VO2 (litres per minute) at a given velocity than the adults, with 1.86 (0.28) and 2.39 (0.20) l min(-1) respectively (at 1.00 m s(-1)). When scaling for size, children had higher VO2 measured in litres per square metre per minute and millilitres per kilogram per minute (divided by BSA and BM) than adults. The VO2 divided by BL was found not to differ between the two groups. The O2 cost of swimming 1 m at a velocity of 1.00 m s(-1) was lower in the children [31.0 (4.6) ml m(-1)] than in the adults [39.9 (3.3) ml m(-1) P