Even though muscles get bigger after 10 weeks of weightlifting, the individual muscle fibers don’t necessarily get thicker — the growth might come from how the fibers are arranged, not from each one swelling up.

Even though muscles got bigger, the actual muscle fibers didn’t get thicker or change type—so the growth might be due to other factors like fluid or connective tissue.

Some people get much bigger and stronger from weight training than others—even when they do the exact same workouts—because everyone’s body responds differently to exercise.

The slow-twitch muscle fibers got bigger no matter what kind of workout or drink the men used—whether they lifted slowly up or down, or drank protein or sugar water.

If you're a young man who already lifts weights, doing workouts with either light weights (lots of reps) or heavy weights (fewer reps)—as long as you push yourself until you can't do another rep—will make your muscles grow just as much either way.

After about 10 weight workouts, your muscles don’t just look puffy from water anymore—they actually start getting bigger because the muscle fibers themselves are growing.