In this study, the hypothesis that improvements in functional and structural measures could be detected in the young, female rat with only 5 days of moderate treadmill training was tested. Eight-week-old female Sprague-Dawley rats were divided randomly into control (n = 10) and training groups (n = 11). Over the 5-day period, running duration and treadmill speed increased progressively. Maximal running time and gas exchange were measured on Day 6. In trained compared with control rats, maximal running time was 54% greater (p < .005), right hindlimb muscle was 16% heavier (p < .01), and end-exercise respiratory exchange ratio (RER) was 17% lower (p < .05). Substantial metabolic and structural adaptations occurred in young female rats after only 5 days of treadmill training. This protocol may be useful in discovering the initiating mechanisms of the training response in the young organism.
A. Eliakim and D.M. Cooper are with the Division of Research at Connecticut Children’s Medical Center, 282 Washington St., Hartford, CT 06106. M.Y. Moromisato and D.Y. Moromisato are with the Division of Respiratory and Critical Care, Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA 90509.