SIR-A 26-year-old woman was treated with high doses of oral glucocorticoids for many years for a very severe asthma bronchiale. Her bone mineral density (BMD; g/cm 2) was measured at our department. She was found to have osteoporosis of the femoral neck (--2.62 SD below the mean value of the young adult). There was no family history of fragility fractures and her osteoporosis was considered to be glucocorticoid induced. At admission to our clinic she regularly performed weight-training, and also some endurance training within the limitation of her asthma. Her daily medication consisted of about 50 mg triamcinolone during this study, and also inhalations of fluticason. Alter tirst BMD measurement, the patient started an exercise program to increase power and explosive muscle strength. The training regimen consisted of different kinds of jumps, e.g. vertical standing jumps, hops on one leg, skate-like side-to-side jumps, and leg lunges forward with small weights applied on the back. Each jump was performed six times in three sets. For the tirst 8 months the exercise program was performed about every second day. During this period the femoral neck BMD increased 28.4%. During this period, the patient was also jumping down the stair steps at home, above five stair steps every time, and two times every day. During the next 3 months the patient's increased intake of glucocorticoids caused massive muscle weakness of the thigh, and no regular exercise could be performed. During the whole training period (l year), BMD increased by 1.8% (total body), 5.3% (lumbar spine), 22.4% (femoral neck), 20.6% (Ward's triangle), 14.6% (trochanter) and 2.5% (lower extremities). The jumps performed by the patient in the present study most likely resulted in high strains in the osteoporotic proximal femur. Since only a few repetitions seem to be necessary to achieve a great osteogenic effect the risk of stress fractures can be minimized. Our results in this case may suggest that jumping activities performed regularly might be very efficient in increasing BMD, and possibly preventing future fractures, in loaded parts of the skeleton in patients with glucocorticoid-induced osteoporosis.