"Girl pushups" refers to pushups performed on your knees. They are generally not called girl pushups anymore, since men or women who are not able to perform full pushups with good form should start with a modified version, such as "girl pushups." It is important to perform knee pushups with proper form, but there is no absolute correct way to position your legs.
The Movement
To do this type of pushup, kneel on the floor or an exercise mat. Position your hands shoulder-width apart, palms flat on the floor. Place your feet on the floor or in the air. Cross your ankles if you prefer. Shift your weight forward until your shoulders are stacked directly above your wrists. Make sure your body is a straight line from your neck to your knees. Lower your body as one unit by bending your elbows, allowing them to flare out to the sides. Stop when your chest almost touches the floor. Press back up, until your arms are straight.
Argument for Not Crossing Your Ankles
The American Council on Exercise provides step-by-step instructions for performing bent-knee pushups in its exercise library. The instructions instruct you to place your feet on the floor. The main reason for placing your lower legs on the floor is to relieve pressure from the knee. If you are on a hard surface or have knee problems, it may be uncomfortable to place a large portion of your weight onto your kneecap. In this case, don't cross your ankles, but set your feet on the floor.
Argument for Crossing Your Ankles
If you choose to have your feet in the air, you can cross your ankles, but this is not the only way to do a bent-knee pushup. You can also place your feet next to each other, but crossing your feet results in more stability. If you place your legs parallel to each other, some of your concentration goes to maintaining this leg position. Crossing your ankles eliminates the need to think about them so you can focus on the pushup itself.
Bottom Line
Performing bent-knee pushups with proper form is important to avoid discomfort and the risk of injury. Allowing your hips to sag places undue pressure on your lower back. Positioning your hands too close or too far out places stress on your wrist joints. However, crossing or not crossing your legs is not a crucial form element of pushups. Do what is comfortable and works best for you.
