When scientists look at how one person changes over time—like how their muscles grow and get stronger together—they find a super strong link. But when they compare different people to each other, that link looks much weaker.

When you look at how one person changes over time, their muscles getting bigger and their strength going up are super closely linked — like almost always together. But when you compare different people to each other, that link isn’t as strong. So how you analyze the data changes what you think is going on.

Just because your muscles get bigger from lifting weights doesn't mean you'll get much stronger — the two don't really go hand in hand.

If you're a young guy lifting weights more often each week, you'll likely get stronger faster—but that doesn't mean your muscles will get noticeably bigger.

If you're a young guy lifting weights more often each week, you'll build more muscle and get stronger—but after a while, your strength stops improving fast, while your muscles keep growing a bit longer.

Doing more sets, reps, and lifting heavier weights doesn’t always mean you’ll grow bigger muscles—some people see big gains with less volume, while others don’t grow much even with more work.