When you lift weights and your muscles get bigger temporarily (that's called the 'pump'), that doesn't actually tell you if your muscles will grow bigger for real over time. Scientists found that muscles that swell a lot right after exercise don't always end up growing the most.

Just because your muscles feel swollen and pumped after a workout doesn't mean they're going to get bigger over time—studies show that even if some people get way more pumped than others, they all end up with about the same muscle growth in the long run.

Scientists aren't sure if the temporary muscle puffiness you get after working out is a good sign that your muscles will actually grow bigger over time. It might work for some muscle groups but not others, so we need more studies to figure this out.

Just because your muscles feel swollen or burn during a tough workout doesn't mean they're getting bigger—studies show that feeling the pump or having sore, burning muscles doesn't automatically lead to muscle growth.

Your muscles can actually swell up bigger right after just one workout than they do after training consistently for several weeks.

Just because a workout makes your muscles feel huge and pumped during the session doesn't guarantee they'll actually grow bigger over time.