If untrained adult men do leg press exercises for nine weeks, their butt muscles won't grow much bigger, no matter how they do the exercises.

A study found that doing leg press exercises, whether with a special pre-exhaustion method or the regular way, didn't make the glute muscles grow much in men who were new to training after 9 weeks. This means the leg press machine isn't great for building these muscles.

When healthy young men lift weights until they're too tired to continue, their muscles grow about the same amount in both their arms and legs, no matter how heavy the weights are.

If a young, healthy man lifts weights for 8 weeks, his muscles will likely get bigger—by about 6%, give or take a little.

Whether you use machines that change resistance as you lift or keep the same weight all the way through, after 20 weeks of training, healthy men gain about the same strength and muscle size either way.

Doing hip thrusts or squats for 9 weeks with the same total work builds your butt muscles just as much, even though hip thrusts feel like they work your butt harder during the exercise.