Even though it seems like your legs are moving forward and backward when you’re running, in reality, the femur (your thigh bone) both rotates and tilts in the hip socket, Kalika explains. It’s the hip adductors—most notably the gluteus medius—that keeps the femur sitting in the socket as designed. (The hip adductors are the muscles that move your legs inward.) Any weaknesses make the joint unstable, and can contribute to poor running mechanics, hip drop (when the pelvis drops to one side), too-narrow stances, and aggravated tissues throughout the entire body, Sauer says.
How to: Lie on your back with your right knee bent and foot flat on the floor (a). Extend your left leg up to the ceiling and wrap a strap around the sole of your left foot (b). While holding both ends with your left hand, extend your right arm directly out to the side in order to anchor yourself (c). Slowly let the left leg fall toward the left while keeping your right side grounded. Hold for six to eight breaths, then repeat on the opposite side.
Grade II (moderate): A larger tear in your muscle that makes it difficult to move and causes a moderate amount of pain, especially when you move the affected muscle, swelling, and tenderness. You may have 5 percent to 50 percent loss of function and you may be limping. You can't go back to sporting activities until the tear is completely healed. These injuries can take anywhere from a couple weeks to a few months to heal, depending on how bad they are.