People get noticeably stronger in just 4 weeks of heavy weightlifting—even before their muscles get bigger—because their nerves learn to fire better.

If you lift weights with either light weights and short breaks, or heavy weights and long breaks—but keep the total work the same—you’ll still build muscle in about 8 weeks. So, there’s more than one way to get stronger and bigger muscles.

When untrained young men lift heavy weights three times a week for five months, they get much stronger—some exercises more than double their original strength.

Even if you don’t lift heavier or do more workouts after six months, your muscles can still get stronger — your brain and nerves are probably getting better at telling your muscles when and how to contract, not just making them bigger.

For women who don't usually lift weights, doing lots of lighter reps or fewer heavy reps both build similar muscle size and make you stronger after two months.

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.