Influence of training, sex, age and body mass on the energy cost of running.

To highlight the influences of age, sex, body mass (mb) and running training on the energy cost of running (Cr) young basketball players [38 boys (BB) and 14 girls (BG), aged 14.2 (SD 0.3) and 12.2 (SD 1.9) years, respectively] were selected to be compared to middle-distance runners [27 men (MR) and 14 women (FR) aged 23.7 (SD 3.4) and 23.9 (SD 4.1) years, respectively]. The Cr was measured during a maximal treadmill test. In each group Cr and body mass (mb) and body height were negatively and significantly correlated. A stepwise regression showed that among both the body dimensions measured, mb was the most important factor in determining the variations of Cr. For the whole group (n = 93) the correlation coefficient was 0.72 (P < 0.0001). For a given mb, there was no significant difference between the Cr of BG, BB and MR: this result would support the hypothesis that the differences in Cr currently attributed to age, running training or sex differences are mainly related to mb. On the other hand, for a given mb, FR showed a significantly lower Cr than the basketball players (P < 0.01 for BG and BB) and than MR (P < 0.05), thus suggesting that women decrease their Cr as a response to running training more efficiently than do men.