3. Tendinitis and bursitis Many tendons around the hip connect the muscles to the joint. These tendons can easily become inflamed if you overuse them or participate in strenuous activities. One of the most common causes of tendinitis at the hip joint, especially in runners, is iliotibial band syndrome — the iliotibial band is the thick span of tissue that runs from the outer rim of your pelvis to the outside of your knee.
However, runners are infamous for imbalances in their hip muscles. The most common weak ones are the hip abductors, the muscles on the side of your butt responsible for moving your leg out away from your body to the side. Lev Kalika, D.C., clinical director of New York Dynamic Neuromuscular Rehabilitation & Physical Therapy, tells SELF that since most runners run, run, and only run, they are constantly training their hip flexors and extensors through a very small range of motion. That can lead the hips to be unstable on the less-frequent occasions when you bring your knee all the way to your chest or thrust your hips forward.
How to: Sit down with your knees bent and feet flat on the floor in front of you (a). Place your right ankle on top of your left thigh and flex your right foot (b). Put your hands behind your body, fingertips facing away from your body and begin to press your hips toward your heels until you feel a stretch through your outer left hip. Keep your back tall and chest open (c). Hold for six to eight breaths, then repeat on the other side.
The main work of your hip flexors is to bring your knee toward your chest and to bend at the waist. Symptoms associated with a hip flexor strain can range from mild to severe and can impact your mobility. If you don’t rest and seek treatment, your hip flexor strain symptoms could get worse. But there are many at-home activities and remedies that can help reduce hip flexor strain symptoms.