Then, light exercise, preferably cross-training if the athlete is dealing with overuse issues, may be undertaken. During the initial phase, aerobic exercise should be confined to "heart rates of 120-140 beats per minute ...this can be slowly built up over the period of 6-12 weeks. The emphasis is increasing volume rather than intensity, and volume should be increased gradually up to one hour per day. Once this is volume is reached, intensity can be gradually increased above the lactate threshold" (Peterson 2011). Preventing overtraining requires moderating the intensity and the duration of work days, and building in one 'cross-training' or rest day into the training schedule. The mental component of overtraining should not be ignored. Not all athletes who train hard experience the syndrome and one reason some athletes are thought to be more vulnerable to overtraining than others is because of personal stresses that can enact an additional toll upon the body. "There is some evidence to suggest that the overtraining syndrome may be a response to an accumulation of both training and non-training stress" (Meehan 2011). Coaches must show sensitivity for athletes' life situations...

Extreme weight loss, or exercising while not replenishing the body's need for calories, can also cause overtraining syndrome. Athletes, particularly females, in sports where weight loss is prioritized, such as figure skating, gymnastics, and running, may experience overtraining as the result of dieting and heavy exercise. Encouraging the athlete to adopt a normal caloric level for her level of activity as well as prescribing rest is essential in such instances.
References

Meehan, Heidi. (2011). Overtraining syndrome. Sports Injury Bulletin.

Retrieved November 17, 2011 at http://www.sportsinjurybulletin.com/archive/overtraining-causes.html

Peterson, Andrea. (2011). Overtraining. Curtin University. Retrieved November 17, 2011 at http://physiotherapy.curtin.edu.au/resources/educational-resources/exphys/00/overtraining.cfm