Lifting heavier weights with proper form was better than lifting lighter weights for building both muscle strength and size in men after 3 months of training.

Lifting weights at different effort levels (from light to heavy) all made muscles bigger and stronger in men over 12 weeks, but the lightest effort wasn't as good as heavier ones.

Lifting weights at different effort levels all help men get stronger and build bigger muscles after 12 weeks, but using the lightest effort isn't as good as pushing harder.

Lifting heavy weights for 10 weeks makes you stronger, no matter how long you rest between sets or how many reps you do, as long as you’re lifting around 80% of your max.

If you're new to lifting weights, doing a moderate amount of workouts each week will make you stronger faster than doing very few workouts — and you'll keep getting stronger week after week for the first 9 weeks.

If you're already experienced with weight training, doing 5 to 10 sets per muscle group each week builds just as much muscle and strength as doing 15 to 20 sets—so going over 10 sets won't give you extra gains.