As to which type of guitar capo will best suit your playing, you will need to match the capo to your guitar, the primary factor being whether you have a flat fretboard, like a nylon-stringed classical or some steel-string acoustics, or if the fretboard is curved, like on most steel-stringed acoustics and electrics.
However, note that other causes of the symptom 'Muscle mass loss' may be possible. Research the causes of these symptoms that are more broader types of symptom than Muscle mass loss: Muscle atrophy (351 causes)
As well, greater changes in muscle mass will occur in individuals with more muscle mass at the start of a training program. Aging also mediates cellular changes in muscle decreasing the actual muscle mass. This loss of muscle mass is referred to as sarcopenia.