When you lift heavy weights, your muscles get faster at producing force quickly, but lifting lighter weights doesn't help much with this. It means your body responds better to heavier loads for...

When young male athletes lift heavy weights until they can't anymore, they get much faster at generating power quickly, but this doesn't happen with lighter weights.

When you lift heavy weights, your muscles get more efficient at using less energy for the same effort, while lifting lighter weights doesn't change much. It's like upgrading your muscles to work smarter, not harder.

Lifting heavy weights until you can't lift anymore makes young male athletes much stronger than lifting lighter weights over 8 weeks, showing that heavier loads train muscles and nerves better.

Lifting heavier weights is much better than lifting lighter weights for building muscle strength in healthy young adults, because it trains your muscles and nerves to work together more effectively for maximum power.

If you lift heavy weights, you get better at doing more reps with heavy weights; if you lift light weights, you get better at doing more reps with light weights — your muscles adapt specifically to the weight you use.