Without question, the hips are the most important joints for athletic performance. They are the most powerful joints in the body, providing the primary source of force for running and jumping. Swinging, throwing and punching all derive their power from the hips.

Hip Anatomy

The hip is a ball and socket joint, with the ball of femur (thigh bone) inserted into the socket of the pelvis (thigh bone). Connective tissue and several large muscle groups keep the hip intact and moving. The hip is similar to the shoulder joint in its construction, but it is much more powerful, stable and resistant to injury.
Hip Flexors
The muscles on the front of the hip—the rectus femoris, iliopsoas, pectineus and tensor fasciae latae—work together to flex the hip. The iliospoas is the lone muscular link between the torso and leg, sharing attachments along the lumbar spine and on the femur. Responsible for flexing the hip beyond a 90-degree angle, the iliospoas is activated when sprinting and jumping from a single leg. Tight hip flexors are often the cause of low-back pain, because they pull the hip forward, causing the low back to extend unnaturally.
Hip Extensors
The gluteals and hamstrings extend the hip. Commonly referred as the posterior chain because they are in the back of the body, these muscles tilt the pelvis backward. Powerful glutes and hamstrings are needed for jumping, sprinting and closed-chain, compound exercises such as Deadlifts and Squats.
Hip Adductors
The adductor muscles (or groin), along with the gracilis and pectineus, adduct the hip, bringing the thigh inward toward the center of the body.
Hip Abductors
The gluteal muscles, specifically the gluteus medius, gluteus minimus and the tensor fascia latae, abduct the hip, moving the thigh out and away from the center of the body.
Hip Internal Rotators
The adductor muscles, along with the medial hamstrings and the tensor fasciae latae, internally rotate the hip and twist the leg inward.
Hip External Rotators
The gluteals and piriformis muscles, along with the sartorius, externally rotate the hip and twist the leg outward.
To be the best athlete that you can be, your hip muscles need to work as a cohesive unit to provide strength and stability. In the next two articles, I will discuss how to strengthen these muscles and increase mobility in the hips, so they can power your running, jumping and other skills without limitation.
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Joe Giandonato, MS, CSCS, is the head strength and conditioning coach at Germantown Academy in Fort Washington, Pa. He has authored numerous articles on a wide variety of topics, including injury prevention, nutrition and improving athletic performance.