All three types of muscle movements—squeezing, lengthening, and holding—can help build muscle in your thighs and arms just as well, as long as you train hard and often enough.

Lifting weights, using machines, or doing static holds all seem to build leg and arm muscles just as well — there's no proof that one way is better than the others for getting bigger muscles.

In untrained men, adding isolated arm exercises to a workout routine may cause the muscles that straighten the elbow to grow more in certain areas than the muscles that bend the elbow, while the bending muscles grow similarly regardless of exercise type.

If you train your quads using either holding a static position with your legs stretched out or doing full squat-like movements, both ways build your thigh muscles about the same amount — neither one is better than the other.

Different muscles in the front of the thigh may respond differently to how close to failure you train: the vastus lateralis may grow more when trained to complete fatigue, while the rectus femoris may grow more when trained with a few reps left in reserve.

If young guys who haven’t worked out in a while switch up their strength exercises for the same muscles, they’ll likely build muscle more evenly across their thighs and arms over nine weeks compared to doing the same moves every time.