It is now well established that strenuous engagement in aerobic endurance sports may cause menstrual problems and hypoestrogenemia-related phenomena, such as osteoporosis. The present study was designed to assess whether the competitive practice of female judoists produces specific physiological changes in menstruation and bone and muscle metabolism. A test group of 17 white female judoists (mean VO2max, 50.9 +/- 2.8 mL/kg.min; mean percent body fat, 16.3 +/- 3.3%), a reference group of oarswomen, and a group of sedentary women participated in this study. Specific metabolic parameters were determined before and after a heavy 5-week pre-Olympic training period. With regard to anthropometrical characteristics, after a period of intensive training, female judoists significantly differed (P < 0.05) from their pretraining values for percent body fat (-2.2%) and number of oligomenorrheic individuals (+28.4%). Mean baseline posttraining luteal phase plasma levels of estrone (78 +/- 26 pmol/L), estradiol (85 +/- 70 pmol/L), LH (7.6 +/- 2.8 IU/L), and progesterone (13.4 +/- 3.1 nmol/L) were significantly lower than those in both reference groups, although pretraining values did not significantly differ from those in a group of oarswomen. Luteal phase posttraining urinary parameters of muscular catabolism (3-methylhistidine, 367 +/- 30 mmol/day) and collagen turnover (hydroxyproline, 678 +/- 14 mumol/L) were significantly higher than those in a group of oarswomen (3- methylhistidine, 183 +/- 18 mmol/day; hydroxyproline, 196 +/- 21 micrograms/mL). Total plasma spontaneous monocyte interleukin-1 activity, an experimental parameter for bone turnover and formation, was significantly higher (P < 0.05) in both female judoists (15.8 +/- 3.0% max) and oarswomen (7.1 +/- 1.8% max) than in sedentary women (5.2 +/- 2.2% max). These findings were accompanied by a subjective feeling of musculotendinous soreness and fatigue. Posttraining values for blood diagnostic enzymes, such as creatinine phosphokinase, glutamic oxalacetic transaminase, lactic dehydrogenase, and uric acid exceeded 2-5 times maximal normal laboratory reference values. We believe that these overtraining-like findings should be further examined to study the eventual causal relationship between hypoestrogenemia and rhabdomyelysis (myoglobinuria) and to fully understand the extent of these results and their importance to the female athlete's health.