Lifting weights three times a week instead of two makes your muscles grow bigger, no matter what type of muscle fibers you have — but it doesn’t make you stronger in one-rep max lifts.

If you're over 60 and lifting weights, doing it more than twice a week probably won't make you any stronger or give you bigger muscles than doing it just twice a week.

For people over 60, adding one extra day of weight training each week might help them get a little stronger, but it won’t make their muscles noticeably bigger.

If you lift weights more often each week, you’ll likely get stronger faster—but that doesn’t always mean your muscles will get bigger. Strength and muscle growth might not follow the same rules.

If you lift weights the same total amount each week, it probably doesn’t matter much whether you do it in 2 big sessions or 5 small ones—your muscles will grow about the same either way.

Higher weekly resistance training volume leads to greater muscle hypertrophy in trained individuals.