Physiologic Responses to Treadmill Running in Adult and Prepubertal Males

• Published in: International journal of sports medicine 1987-08, Vol.8 (4), p.292-297
• Main Authors: Rowland, T. W., Auchinachie, J. A., Keenan, T. J., Green, G. M.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age Factors; Applied physiology; Biological and medical sciences; Biomechanical Phenomena; Body Surface Area; Body Weight; Child; Gait; Heart Rate; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Male; Medical sciences; Oxygen Consumption; Physical Endurance; Physical Exertion; Puberty; Pulmonary Gas Exchange; Running
• ISSN: 0172-4622; 1439-3964
• DOI: 10.1055/s-2008-1025672

Abstract Little data are available directly comparing physiologic responses to endurance exercise in children and adults. To evaluate age related differences during maximal and sub-maximal treadmill exercise, physiologic parameters recorded during testing of 20 active prepubertal boys (aged 9-13 years) were compared with values obtained in nonathletic adult males aged 23-33 years. Maximum oxygen consumption (VO 2 max) was 57.9 ml · kg -1 · min -1 (6.9 SD) in the boys and 48.3 ml · kg -1 · min -1 (4.9 SD) in the adults. Running economy examined both as VO 2 at a treadmill speed of 9.6 kph and as the slope of linear regression of VO 2 at four submaximal speeds was less in boys compared to men when values were expressed per kg body mass. Differences in running economy between the two groups disappeared, however, when related to body surface area. As expected, children had a higher stride frequency at a given treadmill speed, but running stride frequency was unrelated to economy with the two groups. Lower respiratory exchange ratios were observed at maximal and submaximal exercise in the children, which may reflect diminished anaerobic capacity or differences in substrate utilization. These results substantiate the high aerobic capacity previously observed in children and suggest that lower running economy in younger subjects may largely relate to a greater body surface are/mass ratio.