You certainly don't need to isolate your hip adductors and abductors to get them toned and strong. Running is an efficient exercise that firms up all of your lower body muscles -- including your abductors and adductors -- to help you burn calories while strengthening your heart and lungs. As simple as running may appear, both muscle groups work just as hard as your burning thighs as they coordinate with other muscles and the nervous system to maximize your performance.
No single muscle group works alone in its own cubicle when you run. Although your adductors -- inner thigh muscles -- are traditionally described to move your leg toward the midline of your body, they have little to do with adduction since the muscles don't contract when you adduct your leg. When you run or walk, your adductors stabilize your hips and legs to avoid excessive internal rotation that could cause knee pain or an injury when you run. Because the adductors wrap themselves from the front of the lower pelvic bone to the back of your thigh bone, they help to control hip flexion, extension, abduction, adduction and rotation, according to fitness coach Lisa Bonang. Hip abductors, which include the deep gluteal muscles in your rear, also stabilize your hips when you run rather than moving your leg away from your body's midline -- or abduction. Since your pelvis rotates when your run, both adductors and abductors prevent excessive pelvic internal or external rotation.
Natural Accelerator and Brakes
Besides moving your legs like you're side-kicking someone in the stomach, your hip abductors also assist in hip flexion and extension, which is a common hip movement in running. When you run, the back leg and hip abductors accelerate while your adductors and hamstrings in the front leg decelerate your body like a car brake as you land, explains Bonang. Both muscle groups constantly alternate their functions with each stride.
Stronger Butt May Prevent Injuries
Your knee is a pretty dumb joint since its direction of movement is dictated by your hips. Hip adductors and abductors play a constant tug-of-war game as they constantly maintain hip and knee stability when you run. Too much external hip rotation can cause excess knee abduction. Likewise, too much internal hip rotation can cause them to adduct excessively. In a 2008 study published in the Journal of Sport Rehabilitation, women with weak hip abductors demonstrated greater knee abduction than women with strong hip abductors. Researchers in a study published in the Journal of Applied Biomechanics observed that runners with excessive knee abduction tend to have weaker hip abductors, which places more load on the inner part of the knee when they run. Therefore, strengthening the hip abductors can be one way to prevent knee and hip injuries.
No More "Open and Close"
Although it's tempting to hop on the inner-thigh and outer-thigh machine or the donkey-kick machine to strengthen those muscles, these exercises don't consider the movement factors that control running. A better way to improve adductor and abductor functions is to perform a few exercises that improve hip stability, strength and movement. One such exercise is the single-leg squat, which works on hip abductor strength, adductor and core stability and movement coordination. With your own body weight or with the assistance of a rubber tube or suspension cable, this exercise can determine if one side of your body is stronger and more stable than the other side. If you need to work up to this exercise, researchers suggest the quadruped hip extension, floor bridges, the clam and the sidestep to strengthen your abductors, according to a 2013 study published in the Journal of Orthopaedic & Sports Physical Therapy.
- Runners Connect: 2 Tests of Hip Strength and Stability That Can Determine Your Risk of Running Knee Injuries
- Hip Abductor Weakness and Lower Extremity Kinematics During Running
- The American Journal of Sports Medicine: The Association of Hip Strength and Flexibility With the Incidence of Adductor Muscle Strains in Professional Ice Hockey Players
- Runner's World: Bodyworks: Adductor Injuries
- Journal of Applied Biomechanics: Decreased Frontal Plane Hip Joint Moments in Runners with Excessive Varus Excursion at the Knee
- The American Journal of Sports Medicine: Performance on the Single-Leg Squat Task Indicates Hip Abductor Muscle Function
- Journal of Orthopaedic & Sports Physical Therapy: Which Exercises Target the Gluteal Muscles While Minimizing Activation of the Tensor Fascia Lata? Electromyographic Assessment Using Fine-Wire Electrodes
Nick Ng has been writing fitness articles since 2003, focusing on injury prevention and exercise strategies. He has covered health for "MiaBella" magazine. Ng received his Bachelor of Arts in communications from San Diego State University in 2001 and has been a certified fitness coach with the National Academy of Sports Medicine since 2002.