If you gain more muscle and strength when working out, you might also lose more when you stop — your gains and losses seem to go hand in hand.

If you respond really well (or not so well) to a weight training program, you’ll probably have a similar result if you do the exact same program again after taking a break.

When people stop training, their muscles don't get weaker as fast as they shrink — strength sticks around more than size, maybe because the brain and nerves keep working well even as muscles get smaller.

If you're already strength training and you do more sets of bicep exercises each week, your biceps tend to get thicker — and this link isn't just luck, it's a real pattern.

If you're someone who regularly lifts weights, doing more triceps exercises each week might help your triceps muscles get a little bigger—but only a little, and not as much as it helps your biceps.

If you've never worked out before, lifting weights for 10 weeks can make your muscles stronger and bigger — especially in your legs and arms — while people who don’t train see almost no changes.