For young guys who lift weights, squeezing the biceps at the top or bottom of the move doesn’t make a difference in muscle growth when using light weights with blood flow restriction.

For guys who lift weights, doing arm curls with the arm stretched out doesn’t build more muscle than doing them with the arm bent, even when using light weights and blood flow restriction — at least over 3 weeks.

Doing light weightlifting with blood flow restriction four times a week for three weeks can make arm muscles grow a little in young, trained guys — about 4% to 8% bigger.

When people do light weight training with blood flow restriction on their biceps, the muscle grows evenly no matter if they do the exercise with their arm bent a lot or a little — growth looks the same along the whole muscle.

If you're new to lifting weights and do bicep curls with heavy weights, then wrap your arm tightly after exercising, you might end up with slightly less muscle growth in your upper arm compared to not wrapping it at all.

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.