The aim of this pilot study is to test feasibility of assessment methods and immediate responses to two different strength training sessions, maximal strength training and hypertrophy strength training, among persons undergoing treatment for eating disorders. The study will combine quantitative methods to assess immediate physiological and affective responses to two adapted and supervised strength training sessions. Following the sessions, qualitative in-dept interviews will address the participants' experiences with the strength training sessions. A total of 30 participants from different treatment settings for eating disorders will be recruited to participation. Assessments include symptoms of eating disorders, muscle strength, physical activity behaviour and motivation, blood pressure, heart rate variability, body temperature, lactate, percievied exertion and affective responses. The findings of the study will be utilized in a randomized clinical trial with strength training as part of treatment for eating disorders.