If you do targeted strength training for a few weeks, the muscles you work will grow bigger, but the muscles you don't use during those exercises might actually shrink a little bit. This happens because your body adapts specifically to the exact movements you're doing.

People grow muscle at very different rates — but each person tends to grow their arms and legs similarly, no matter what weight they use. This means your genes and biology matter more than how heavy your weights are.

Whether you're working your quads, calves, or biceps, stretching them fully during exercises helps them grow bigger — this works for many different muscles, not just one.

If a young, healthy man lifts weights for 8 weeks, his muscles will likely get bigger—by about 6%, give or take a little.

The more you lift each week for a specific muscle, the more it grows—but after a point, doing even more doesn't help much.

Doing your workouts more often per week doesn’t seem to help you build more muscle, as long as the total amount of lifting stays the same.