Not only will you start building strength in your quads, but you'll also learn how to straighten the legs without hyperextending them. IF you thought you were taking the easy way out doing push-ups on your knees, think again. If your right hand is pressing down on your right shin firmly, you're pushing the tibia back. When you bring your chest to the ground, your hands should hit your armpits. Some people might prefer doing a bench press, TRX push-upor medicine ball chest pass instead, for example, she says. As an alternate strategy, you can place a block or some other firm object 6 to 7 inches high under your calf, and make sure you do not let your calf press into the block as you move into the pose.
They require no equipment other than your body, they are easy to modify for your fitness level and man, oh man, are they effective.
And, for the record, "girls" are really strong. As you begin to correct your knee alignment, you may become aware that your hyperextended knees are part of a bigger posture problem.