When the total amount of weight training is the same, exercises that work one joint at a time and exercises that work multiple joints at once lead to similar changes in body fat and muscle mass in young, active men after 8 weeks.

If you're someone who's been lifting weights for a while, splitting your workouts into 2 days a week works just as well as doing them 4 times a week — as long as you're doing the same total amount of exercise over time.

Doing extra arm isolation exercises like bicep curls and triceps extensions doesn't help you get stronger or build more arm muscle than just doing big compound moves like bench presses and pull-downs — at least not for beginners after 10 weeks.

For guys who don't usually work out, doing regular weightlifting cuts more overall body fat and thigh fat than a special pre-exhaustion method over 9 weeks, probably because you lift more total weight with the regular way.

In young, active men, doing compound exercises like squats and deadlifts for 8 weeks leads to bigger gains in strength and aerobic fitness than doing isolated exercises like bicep curls, when the total amount of work is the same.

For men who already lift weights, doing either high-intensity or high-volume workouts for 8 weeks didn't make a big difference in leg strength or muscle size.