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.

Performing resistance exercises with either isolated or compound movements can increase maximum strength not only in the exercises done but also in other unrelated movements, suggesting that the nervous system adapts in a widespread way.

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.

Lifting weights with one joint (like leg extensions) transfers better to holding a static position than complex lifts like squats, because it’s easier for your body to use the same muscle pattern in both cases.

Doing just one set of strength exercises a few times a week can still build significant muscle strength and improve daily physical function, whether you are new to working out or already experienced. Cutting down on the number of sets does not stop your muscles from getting stronger as long as you are working the big muscle groups.

For exercises that move just one joint—like bicep curls—lifting heavier weights leads to better strength gains than lifting lighter weights, even if both are done until exhaustion.