A good bit of research shows that long-term endurance training is associated with lowered testosterone levels. There is much less research showing the effects of sprint training on testosterone levels.
However, I did manage to find a short study on this: Journal of Sports Sciences, Vol. 23, Issue 2, February 2005, pg. 187-188 (no abstract). Here they compare testosterone levels among different groups of males:
- Sprint Trained - 9.11 (ng/l)
- Endurance Trained - 7.05 (ng/l)
- Sedentary - 8.19 (ng/l)
Since this data is a cross-section, it does not establish cause-and-effect. In other words, it's possible that men with low testosterone self-select into endurance running, and men with high testosterone self-select into sprint running. However, this data is very suggestive that sprint training may increase testosterone in men.
A good bit of research shows that long-term endurance training is associated with lowered testosterone levels. There is much less research showing the effects of sprint training on testosterone levels.
However, I did manage to find a short study on this: Journal of Sports Sciences, Vol. 23, Issue 2, February 2005, pg. 187-188 (no abstract). Here they compare testosterone levels among different groups of males:
Since this data is a cross-section, it does not establish cause-and-effect. In other words, it's possible that men with low testosterone self-select into endurance running, and men with high testosterone self-select into sprint running. However, this data is very suggestive that sprint training may increase testosterone in men.