Skeletal muscles are essential for movement as well as for survival. Knowledge about the organ skeletal muscle is underrepresented. Ageing and multiple chronic diseases are accompanied by loss of muscle mass, termed “muscle wasting”. Nevertheless, muscles are one of the target organs within the rehabilitation process. This review highlights the role of skeletal muscles from various aspects, diagnostic procedures to quantify muscle mass and strength and, most importantly, lists countermeasures to muscle wasting. Although structured and progressive strength training is the cornerstone in the treatment of muscle wasting, several other methods exist to slow down or reverse the process of muscle wasting. Among them are neuromuscular electrical stimulation and alternative exercise modes, positioning, stretching and, as an emerging field, drug therapy.