Abstract

Performance and hormones were determined in eight middle- and nine long-distance runners after an increase in training volume or intensity. Seven runners participated in both studies. The objective was to cause an overtraining syndrome. The mean training volume of 85,9 km/week increased within 3 weeks to 176.6 km/week during ITV and 96-98 of training volume was performed as long-distance runs at mean(s.d.) 67(8) of maximum capacity. Speed endurance, high-speed and interval runs averaging 9 km/week increased within 3 weeks to 22.7 km during ITI, and the total volume increased from 61.6 to 84.7 km. A plateau in endurance performance and decrease in maximum performance occurred during ITV, probably due to overtraining, with performance incompetence over months. Nocturnal catecholamine excretion decreased markedly (47-53), contrary to exercise-related plasma catecholamine responses, which increased. Resting and exercise-related cortisol and aldosterone levels decreased. Improvement in endurance and maximum performance occurred during ITI indicating a failure to cause an overtraining syndrome in ITI. Decrease in nocturnal catecholamine excretion was clearly lower (9-26), exercise-related catecholamine responses showed a significant decrease, cortisol and aldosterone levels remained almost constant, exercise-related prolactin levels decreased slightly. Verf.-Referat