You can build muscle just as well by lifting light weights with your blood partially squeezed off, as you can by lifting heavy weights—so maybe it’s not the weight itself that matters most, but how much your muscles burn and swell up.

Doing heavy weightlifting with your legs squeezed to restrict blood flow doesn't make your muscles grow more than just doing heavy weightlifting normally — at least not for most people who haven't trained before.

If you lift heavy weights with a special band that cuts off some blood flow, it doesn’t make your muscles stronger or bigger than just lifting heavy weights alone—even though your muscles feel more burned.

When you wrap your arm tightly and lift light weights, your muscles still grow — and your body turns on the same growth signals as when you lift heavy weights, which hints that the burning feeling might be key.

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.

When you do heavy lifting while restricting blood flow to your muscles, your muscles feel more burned and stressed during the workout than when you lift heavy without restricting blood flow.