Strength training has been found effective for enhancement of bone health, muscle strength and body composition among premenopausal women from the general population, however it is unclear to what extend strength training might improve these parameters among women with eating disorders. The aim of this study is therefore to examine acute and long-term effects of strength training among persons with eating disorders. The study is a randomized, controlled, single-blinded trial with three intervention groups and one control group. The three intervention groups will perform different volumes of strength training. The intervention period is 16 weeks with three sessions per week. At pretest, posttest, and 6 months, 12 months and 24 months follow-up, the following variables will be measured: bone health, muscle strength, power, body composition hormone levels, physical activity level and compulsivity, body awareness, quality of life, and eating disorders psychopathology. Qualitative in-depth interviews will be carried out to explore the participants' experiences with strength training. The study is carried out in Norway, and is performed in collaboration with Telemark University College, University of Agder, Norwegian school of sport sciences and Modum Bad psychiatric center. The results from the study might implicate on strength training as part of treatment for eating disorders.