No matter how tight you make the band or how wide it is when you do blood-flow restriction training, your muscles still grow about the same amount — so you don’t need to stress over getting the exact settings perfect.

When you do blood flow restriction training—like wearing tight bands on your arms or legs while lifting light weights—you build muscle mainly because your muscles fire harder and earlier, not because of the burn or buildup of waste products.

If you're new to lifting weights, adding blood flow restriction after your workout won't make your muscles grow any more than just lifting weights by itself—even if you do the same amount of work.

When people do exercise with bands that squeeze their muscles afterward, some people’s muscles grow a lot, others barely grow at all—even though on average, the whole group doesn’t show much change. It’s like everyone reacts differently to the same workout trick.

Doing light weight training with restricted blood flow can still make your arm muscles grow bigger — and it doesn’t cause swelling or damage, according to a 3-week study on people’s biceps.

When people do light weightlifting with restricted blood flow, their slow-twitch muscles can grow as much or more than their fast-twitch muscles, which is different from heavy lifting where fast-twitch muscles usually grow more.