Comparison of changes in testosterone concentrations after strength and endurance exercise in well trained men.

Changes in the testosterone concentrations after single sessions of endurance and strength training were measured in seven well trained men, experienced in both forms of training. Both training sessions were rated as hard to very hard on the Borg scale. Blood samples for testosterone measurements were taken before, immediately after, and 2, 4 and 6 h after the training sessions as well as the next morning.