The longitudinal development of running economy in males and females aged between 13 and 27 years: the Amsterdam Growth and Health Study.

The purpose of this study was to describe the longitudinal development of running economy [defined as the oxygen uptake (VO2) at a submaximal running speed] in males and females from teenage to young adult age using data from the Amsterdam Growth and Health Study. Submaximal VO2 (in ml.kg-1.min-1) was measured in 84 males and 98 females while they ran on a treadmill at a constant speed of 8 km.h-1 for 6 min at three different treadmill slopes (0%, 2.5% and 5%). This test was carried out six times, on the same subjects at the ages of 13, 14, 15, 16, 21, and 27 years. The longitudinal development of running economy in males and females was analysed using a two-way analysis of variance for repeated measurements. At all three slopes, a significant decrease in VO2 with increasing age was found for both males and females, implying a significant increase in running economy for both sexes. Males showed significantly higher VO2 values than females at all ages measured and for all three slopes, suggesting that females have a significantly higher running economy than males. In order to make a better comparison of the VO2 of individuals of different sizes, allometric models were used; power function ratios were constructed in which body mass was expressed to an exponential power. Following this analysis the difference in submaximal VO2 and running economy between males and females appeared even larger.