After eyeing these kinds of things suspiciously for a while I decided to give them a go, and actually this style of training does encourage muscle volume development when used. I haven't used them long enough to track how long-term the gains are, but you can probably find that out elsewhere as that aspect isn't product specific. The bands are long enough to use on both my arms and legs (though I would expect folks with thicker thighs than mine might not find that to be the case), and the they are comfortable to tighten up. You do need to be a bit mindful when the buckle is close to the skin and there isn't some cloth between you and the buckle-- you can give yourself a bit of a pinch as you pull it tight if you aren't careful. They are very easy to use on legs, and the buckle makes applying them to your arms a fairly easy affair. Maybe most importantly, the are quick and easy to release at the end of the workout, where you might find yourself quite ready to let the blood flow back into your exhausted limb.