If you use a tight band on your arm or leg while lifting heavy weights or resting between sets, it won’t make your muscles work harder—measured by electrical signals—when you’re a young guy who hasn’t trained before.

If you're a young guy new to weightlifting and you use a blood pressure cuff to restrict blood flow while lifting, it doesn't matter whether you squeeze the cuff while you're pushing the weight up or while you're resting between sets—either way, you'll gain the same amount of strength and muscle.

After doing heavy weight training, if women who’ve never trained before use a tight band around their arm afterward, their arm muscles don’t get any thicker—but men’s muscles still grow normally.

If you wear tight bands around your arms or legs only when you're resting between weightlifting sets, your muscles will produce more lactic acid afterward than if you wear them while lifting or not at all—but that extra burn doesn’t make your muscles grow bigger or stronger.

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.

If young women do light weightlifting while wearing special bands that squeeze their arms or legs, they can get stronger and their muscles can grow bigger in just four weeks—without lifting heavy weights at all.