Hip flexor pain is most likely to occur when you’re either raising your knee or bending at the waist, since these are two movements in which hip flexors play a major role. The flexor muscle promotes flexion, which is a movement that decreases the angle between two bones. Not all of the muscles in the body do this of course; in fact, only a small percentage of the muscles in the body could be classified as flexors.
To be more precise, flexors are muscle and tendon combinations. There are, for example, three flexors that control the movement of the arm at the elbow, a movement that decreases the angle between the upper arm bone (humerus) and the forearm bone (radius). These three flexors are called the brachialis, the brachioradialis, and the more familiar biceps brachii. Contracting these muscles will cause the forearm to move inward towards the upper arm. Flexors also surround other joints besides the elbow, including the knee, shoulder, ankle, and hip.
The anatomy of the hip flexors is a little more complicated than that of the arm flexors in that there are more of them, 10 on each side of our hip to be exact, and some of these muscles play a greater role in flexing our hip than do others. The hip flexors primarily attach the pelvis and the lower spine to the upper leg bone (femur). These flexors allow you to sit up, bend at the waist, rotate your waist, and lift your upper leg. Understanding what these flexors are, and why they may be a source of hip pain, can pay dividends.
The 20 Hip Flexors
The muscle that plays the most important role in the flexing of our hip is the iliopsoas, which consists of three muscles that also aid in rotating our hip and are known as the inner hip muscles. The three muscles that make up the iliopsoas are the psoas major, the psoas minor, and the iliacus muscle. There are of course two of each of these muscles, one for each side of our hip.
- The psoas major is a rather long muscle that extends from the lumbar region of the spinal column to near the top of the femur. It consists of two parts, a surface or superficial muscle, and a deeper muscle. When the psoas major contracts, it tends to pull the femur towards the vertebrae, or vice versa, enabling you to either raise your knee, or bend at the hip.
- The psoas minor is a smaller muscle that follows the same general path of the psoas major. It is sometimes referred to as the weak trunk flexor.
- The iliacus runs from the innominate bone and the spine and joins the psoas major near the top of the femur. It not only helps to raise the knee but also plays the major role in sitting up from a lying position. In other words, it helps to bend the trunk forward and is therefore a very strong muscle.
- Two other flexors are located towards the back of the thigh. One of these is the rectus femoris, which is one of the four muscles that make up the quadriceps muscle group. The other is the sartorius.
- The rectus femoris originates at the pelvic bone, just above one’s hip or acetabulofemoral joint. It runs down along the inside rear portion of the femur, terminating just behind the kneecap. The rectus femoris flexes the thigh at the hip and also extends the leg at the knee.
- The sartorius is a long, slender muscle. It is in fact the longest muscle in the human body, and originates from the upper third of the pelvic bone, just under the widest part of the pelvis. From there, the sartorius runs across the front of the acetabulofemoral joint, down the inside of the leg, and terminates just below the knee joint on the larger of the lower leg bones, the tibia. The sartorius flexes, abducts, and laterally rotates the thigh at the hip. It is the sartorius that is the most common source of pain associated with the hip flexors since there are a number of different things that can disrupt its actions, the most common being bursitis of the knee, which can cause inflammation and tendonitis in the tendons of the sartorius, which will then be felt as a pain in the hip area.
Another of the hip flexors is the tensor fasciae latae, an abductor muscle, which is one of the gluteal muscles.
- The tensor fasciae latae, located on the outside of one’s hip, arises from the back of the upper surface of the innominate bone, encases the pelvis, and is inserted in the iliotibial tract, where it becomes a part of the iliotibial band, or IT band. The IT band in turn terminates at the tibia. This flexor assists the gluteus maximus during hip extension, and also during extension of the knee. It is particularly active when walking, being one of the muscles that helps to move the leg out and away from the median line of the body. One of the functions of this flexor is to help a person maintain their balance when standing on the opposite leg.
The four flexors located in the medial fascial compartment of the thigh are more commonly known as the hip adductor muscles.
- These muscles serve to assist in moving the legs inwards towards the median line of the body, and consist of the adductor longus, the adductor brevis, the adductor magnus, and the gracilis. These are large, powerful muscles located at the back of the thigh that attach to near the pubic region and onto the leg muscles. These muscles are used when you cross your legs. They are also one of the more commonly injured muscle groups. An injury to any of these four flexors, most often a strain, is usually referred to as a groin pull.
Having looked more closely into the anatomy of the hip flexors, the sources of at least two of the more common types of pain associated with them can now be understood. Injuries to the sartorius, or to one of the adductor muscles, are common causes of pain.
Muscle Strain – A Common Cause of Hip Flexor Pain
A muscle strain is generally the predominant cause of hip flexor pain. Since all of these flexors are involved, to one extent or another, in activities such as walking, running, kicking, and even hiking, swimming and cycling, it is little wonder that they can suffer from either overuse, from tearing due to sudden movements, or from not being sufficiently warmed up or stretched. These flexors can also be injured if the body moves in an unbalanced manner for too long, or when they attempt to compensate for a weakness elsewhere in the skeletal muscle system, especially a weakness of the abdominal muscles. Improving core muscle strength is one way to help avoid flexor injury and pain.
Another reason for experiencing pain in the group of muscles that allow our hips to move forward is from sitting too long. Those who work in sedentary occupations, or simply watch too much TV, can, over time, experience tightness in these muscles. Activity, especially sudden activity, can then cause excessive stretching and injury.
The Importance of Warming Up and Stretching
Stretching and warming up before engaging in strenuous activity is just as important for your hips as it is for any other part of your body. All too often, stretching is focused on the leg muscles, particularly the calf muscles and the hamstrings. That is fine, but it will do little to prevent muscle strains in the hips or in the lower abdomen. Stretching exercises should be complete, and should involve a good deal of hip bending, hip rotation, and the raising and lowering of the upper legs. Getting up and stretching or just walking around if you’ve been sitting for any length of time can also help to avoid the pain associated with the flexors. Adding a few simple exercises to your daily exercise routine would not be a bad idea.
Six Simple but Effective Exercises
Hip flexor exercises should be done with at least three purposes in mind: One is to strengthen this muscle group; another is to loosen the muscles that have a tendency to become tight; and the last is to add flexibility to the individual muscles as well as to the muscle group as a whole. The combination of strengthening, loosening, and adding flexibility will lessen your chances of injury and the resulting pain. Before attempting to use weights to help in strengthening these muscles, or even before doing any stretching exercises, it is always a good idea to go through a set of motions such as leg lifts and leg swings to warm the muscles up. Here are six excellent exercises, three for strengthening the hip flexors and three for loosening up any tight muscles as well as making them more flexible. The strengthening exercises can be done on a machine, or as described below accomplished simply while sitting or standing using, an elastic strap to provide resistance.
- Hip External Rotation: While seated, place the elastic strap around one ankle and, while keeping your knees together, move your foot by lifting your leg. Do a set of 10 repetitions for each leg, slowly increasing the number of sets over a period of time to at least three. For each repetition, lift your foot and leg, while slowly counting to two, hold for a count of two, and release down to a count of two. This will work the muscles in both the inner and outer part of the thigh.
- Standing Hip Flexor: While standing and facing away from where the strap is anchored, place the strap around one ankle and, keeping one leg straight with your foot on the floor, slowly lift your other leg forward, which you also keep straight, using the same 2 – 2 – 2 count. Do at least 10 reps with each leg. You should feel this exercise in your quadriceps, the flexors that make up your groin muscles, and in your IT band.
- Hip Abduction: Loop the elastic band around one of your ankles, and stand so that the band passes just in front of your other foot. Move your leg sideways and away from your other leg, again with a 2 – 2 – 2 count. This exercises the muscle that helps you to maintain your balance while standing on your opposite leg. It is very important that you try to keep this muscle strong and flexible.
- Lunges: Lunges are easy to perform. They are excellent exercises for those whose quadriceps tend to tighten up or lack flexibility. Lunges also tend to lengthen both the psoas and iliac muscles, two muscle groups that are somewhat susceptible to strains. If you hold your rear knee and lower leg aloft while performing a lunge, the exercise will also serve to strengthen your hip flexor muscles.
- Hamstring Stretches: Hamstrings are not considered part of the hip flexor group, but it is important that there is a balance between your hamstrings and your hip flexors. If this balance is not maintained, it can be detrimental to one or the other of the muscle groups, and can lead to problems both with your gait and with your posture, and possibly lead to lower back pain as well. A good hamstring stretch is to lie on your back, place the strap around one foot and lift your straight leg as close to vertical as possible. Combine this exercise with lunges, and with the groin-opening exercise that follows.
- Groin-Opening Bends: These stretch and lengthen tight groin muscles, and therefore help to prevent groin injuries. They are done by first assuming a wide-legged stance and then by bending both forward, and to either side of the waist. This is one of the best ways to exercise all of the muscles of the inner thighs. The combination of bending forward and rotating your hip will generally leave you feeling a little better. Take your time when doing this exercise, and enjoy it.
Hip Flexor Pain Treatment
You’ve done your warm ups, your stretches, and your strengthening exercises, and you still somehow managed to strain one of your hip flexors. It can happen. Strains go by many names, ranging from a groin pull or injury, a psoas strain, an iliopsoas strain, or simply hip flexor strain. No matter what the name, the pain is there, and the strain causing it can be anything from a mild Class I strain to a major Class II strain, where a muscle has been badly torn or a tendon has been damaged. Severe strains often require the services of a physician, but you can usually treat mild strains yourself using a combination of rest, ice, and medication. One approach is to initially apply a cold compress (not an ice cube) to the painful area for up to 30 minutes several times a day. After two or three days the pain should subside. If not, see a doctor. In addition to the ice treatment, and giving these muscles an adequate amount of rest, it is sometimes helpful to take an anti-inflammatory medication.
Even a mild strain will often take time to heal, and a Class II or II strain can take a very long time. Ask any athlete who has ever suffered a severe groin muscle injury.
Sometimes the pain we feel is a referred pain, where our nervous system is telling us that the pain we are experiencing is from somewhere other than where the actual problem lies. This is seldom the case with hip flexor pain. Pain will tend to be felt on the outer or inner thigh, or in the groin area where the muscle that has been strained is actually located. There are a few exceptions, as sometimes pain will be felt in the lower back or even the lower leg. If you are familiar with your hip flexor anatomy however, you can often tell which muscle, or group of muscles, is in need of attention.