If you're new to lifting weights, having more muscle at the start doesn't really mean you'll gain more muscle from training — it's not a strong predictor of results, especially once you account for...

If you're new to lifting weights, things like how much you eat, how much protein you get, how old you are, or your BMI don’t really help predict how much muscle you’ll gain in the first few months.

If you're new to strength training, your bone size or density doesn't really predict how much muscle you'll gain in the first few months—people with all kinds of frames tend to gain muscle at similar rates.

If you're a healthy man between 18 and 40 years old, your starting height, weight, and age won't really change how much muscle you build from working out. Basically, everyone in this age group tends to gain muscle at roughly the same rate when they follow the same training plan, no matter their body size.

Doing more weightlifting each week helps you build more muscle—but only up to a point. After a certain number of sets, doing even more doesn’t help much more.

Doing more sets in your weight workouts might actually make you gain less muscle—each extra set could slightly reduce your muscle growth, so more isn’t always better.