 Some studies in mice also indicate attenuated activity in some of the pathways responsible for degradation of muscle proteins with aging especially autophagy. As a result, damaged proteins and organelles are not removed as effectively as they should, which could ultimately compromise the muscles ability to produce force. In addition, reduced efficiency of mitophagy and lipophagy two specific forms of autophagy, may indirectly affect single fiber specific force, through oxidative damage by reactive oxygen species ROS and increased levels of intramyocellular lipids, respectively. Although animal studies indicate attenuated autophagic function, exercise seems to restore the activity in this pathway. Whether this also is the case in humans is unknown. Thus, the purpose of this study is to investigate how the different factors contributing to reduced muscle quality in frail elderly individuals, with emphasis on the relationship between muscle quality and autophagy, may be counteracted by a specific strength training program targeting muscle quality and muscle mass. 