Physiological response during running in athletes with similar body mass but different body composition

Objective. - The aim of the paper was to evaluate the physiological response during running in athletes with similar body mass but different body composition. Material and methods. - Thirty-three recreational athletes composed three study groups: control, increased body fat (HBF) and increased lean body mass (HLBM). The HBF and HLBM groups were similar in total body mass and the pattern of mass distribution within the body, but differed significantly in body composition. Maximal oxygen uptake and second ventilatory threshold were determined in an incremental test. Physiological response and running economy were evaluated during submaximal runs performed at four different speeds. Results. - Absolute oxygen consumption during the run was similar in the HBF and HLBM groups, and at the same time, significantly greater than in the control group. Comparison of the groups showed similar running economy expressed as oxygen uptake relative to body mass, and as the amount of oxygen needed for running 1 km. Only the relativization of oxygen uptake to lean body mass showed significant intergroup differences. Work intensity during running was significantly larger in the HBF than in the control group. In the HLBM group, the physiological response during runs at lower speeds was similar to the control group. With an increase of running speed, running economy in the HLBM group became more similar to the running economy of the HBF group. Conclusions. - Increased body mass resulting from high body fat adversely affects the running economy. In runs that exceed the second ventilatory threshold, physiological response is similar in participants with increased body mass, regardless of their body composition. (C) 2015 Elsevier Masson SAS. All rights reserved.