In the present study, 8 young girls participated as the experimental group and another 8 as the control group in a study of the effect of training on maximal aerobic power. The experimental group practiced a 915-m endurance run 6 days per week. Both groups underwent treadmill tests to check the training effect every 6 months. After 18 months, the experimental group was significantly superior to the control group in maximal aerobic power. The training program brought about this effect in only 12 months. The increased maximal oxygen uptake was mainly due to the increase of stroke volume rather than to the improvement of maximal arteriovenous oxygen content difference. There were seasonal cycles in the change of the endurance run performance: longer times in spring to summer and fall to winter and shortened times in summer to fall and winter to spring.
Shigehiro Yoshizawa is with Exercise Physiology Laboratory, Faculty of Education, Utsunomiya University 321, Japan. Hiroko Honda is with Kokugakuin University, Tochigi College 328, Japan. Naka Nakamura is with Tochigi-ken Training Center 321, Japan. Kiyohide Itoh and Nobuo Watanabe are with Kanuma Senior High School of Commerce and Technology 322, Japan.