Gymnasts must remain on the lean side of lean to be effective competitors at the highest level (Nelson et al., 1983; Sands et al., 1992, 1995). Not surprisingly, concern about excess body weight is common in gymnastics (Anorexia/Bulimia Association, 1994; American College of Sports Medicine, 1997; Leglise, 1998; Nattiv & Lynch, 1994). Female gymnasts and their coaches in the US are therefore reluctant to use weight training, in spite of abundant evidence of the benefits of weight training for sports requiring strength. Their concern is that the gymnast will develop excessive body and muscle mass ("bulk up") and thus become too heavy to perform effectively.
Contiune reading the article here: http://www.sportsci.org/jour/0003/was.html