If rats lift weights slowly for longer periods, they grow less muscle than if they lift quickly or at a medium pace—even if the total effort is the same—because how fast they move matters for muscle growth.

When rats do strength exercises with very slow, long reps, they don't push as hard as when they do faster reps—even if the total effort is the same—and that might be why their muscles don't grow as much.

When rats lift weights with different numbers of reps, their muscles show the same early biological changes no matter if they do few or many reps—and those early changes don’t tell us which workout will make muscles grow bigger over time.

Even the middle parts of your muscles grow more when you stretch them fully during workouts — it’s not just the ends that benefit from full range of motion.

Getting stronger from lifting weights doesn’t always mean your muscles are getting bigger—and vice versa. Strength and size don’t go hand in hand.

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.