To examine the research questions, we will use a multi-methods approach. We will conduct a randomized controlled trial with four groups (n=200), these groups will be followed during the 16 weeks intervention period and up to two years follow-up. We will use both quantitative objective and self-report assessment methods, and qualitative in-depth interviews. To answer RQ 1 and RQ 2, objective assessment methods such as dual x-ray absorptiometry (DXA), blood samples and strength tests using squats and bench press will be conducted. RQ 3 and RQ 4 are answered by using standardized self-report instruments. Ambulatory continuous blood pressure monitors will be used during the first strength training session to answer RQ 5. RQ 6 will be answered by selecting participants to be informants in a qualitative semi-structured in-depth interview. To answer RQ 7-10, follow-up 6 months, 12 months and 24 months after the intervention will be conducted. We have chosen a randomized controlled design because it is the gold standard when examining effects of different treatment interventions. However, we believe it is important to take the participants' experiences into account, because this can give valuable additional information about the clinical significance of the interventions. Such information is valuable when considering the use of strength training intervention in clinical settings in the future. In evidence-based practice, it is essential to considerate both clinical expertise, a wide research perspective and the patients' preferences and subjective experiences of needs. This justify the use of a multi-methods approach where both quantitative objective and qualitative data are included.