Lifting heavier weights makes you stronger faster in the first few months, but both heavy and lighter weights build similar muscle size over time if you do enough total work and push yourself hard.

If two groups of young men lift weights with the same total effort but one rests longer with heavier weights and the other rests briefly with lighter weights, they both get just as strong after 8 weeks—even though you’d think the heavy weights would win.

Lifting heavy weights until you can't lift anymore makes young male athletes much stronger than lifting light weights over 8 weeks, even if both make muscles grow about the same size.

Lifting weights until you can't do any more reps, whether with light or heavy weights, makes muscles grow bigger in fit young men after 8 weeks. It shows that pushing to your limit is what really matters for growth, not how heavy the weights are.

Lifting heavier weights makes you stronger and improves your brain-muscle connection more than lifting lighter weights, even if you do the same total amount of work and build the same muscle size.

Lifting heavier weights (fewer reps) leads to bigger strength gains than lifting lighter weights (more reps), even if both are done until exhaustion.