Interval training helps elite athletes get fitter without overtraining
Elite athletes usually have a jam-packed training schedule. Adding more training often means over-training, which can results in a drop in testosterone level, muscle breakdown and reduced performance. Fortunately, though, there's interval training: a possible solution according to sports scientists at Tarbiat Modares University in Iran. They discovered that free-style wrestlers become even fitter and produce even more testosterone if they add interval training to their routine.
Study

The researchers got 8 experienced male wrestlers to do interval training twice a week for 4 weeks. The training consisted of six 35-m sprints, with 10 seconds rest between sprints. A session lasted just 4 minutes, including a warming up and a cool down.On one occasion the wrestlers did their interval training on a day when no other forms of training were planned; on the other occasion they did the training during a separate part of the day. The interval training was never done just before, during or just after another training element.
A control group of 7 wrestlers continued to train as before, doing the same amount of training except for the interval training as the experimental group. They did strength training twice a week, plyometric training once a week, and wrestled three times a week. Friday was their day off.





Results
The testosterone level of the men in the experimental group rose by a statistically significant 19 percent. The men's free testosterone level rose by 8 percent; their cortisol level went down by 13 percent. These two effects were not statistically significant.








The maximal oxygen uptake in the experimental group increased by 5 percent: a statistically significant effect.
And finally, the interval training resulted in the wrestlers being able to generate more power in the Wingate test: a standard measure of anaerobic capacity. In the figure below [click for a larger version] you can see that the wrestlers' anaerobic and aerobic capacity increased as a result of the interval training.





Conclusion
Because interval training is so quick to do it's a great way for athletes to make improvements to their condition even though they're on the brink of over-training because of a high training volume, the Iranians conclude.

"However, it must be considered that anaerobic types of training are very intensive; thus, the volume of the training should be monitored and increased with caution; otherwise, the performance may be reduced", they warn.
"Therefore, the use of a higher number of sprints should be investigated further."
Source:
J Strength Cond Res. 2011 Sep;25(9):2392-9.