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.

When you lift heavy weights while restricting blood flow to your muscles, your muscles show bigger changes in oxygen use and blood volume during the workout than when you lift heavy weights normally—this means your muscles are working harder metabolically.

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.

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.

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.

Some people grow more muscle with regular heavy lifting, others grow just as much or more with heavy lifting plus blood flow restriction — there’s no one-size-fits-all answer.