You can't build real muscle strength just by working out a few times—you need to stick with it for weeks, because the first few workouts just make your muscles look puffy, not stronger.

You can't really grow bigger muscles until you've done about 18 weightlifting sessions—your body needs time to adapt before it starts building real muscle.

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 you start lifting weights, your muscles might look bigger right away, but that’s just because they’re swollen and rearranging inside—not actually growing. Real muscle growth takes about 6 to 8 weeks to show up in measurements.

If a young, healthy man lifts weights for 8 weeks, his muscles will likely get bigger—by about 6%, give or take a little.

When untrained young men lift weights until they can't anymore three times a week for six weeks, and they do the same total amount of work, their muscles grow about the same amount whether they lift heavy or light weights.