The iliopsaos muscles are a part of the set of tissues that form a part of the hip joint known generally as the hip flexor muscles. These muscles are necessary in the forward flexing movement of the hip. The iliopsaos are also crucial to the ongoing stability of the lower lumbar region of the back. Weak or otherwise poorly positioned iliopsaos muscles are frequently cited as a key contributing factor in the weaknesses associated with an inefficient running stride. This muscle is connected to the femur (thigh) by means of the iliopsaos tendon. The hip joint over which the iliopsaos is positioned is defined by the connection made between the femur and the portion of the pelvis known as the acetebulum, which together form the ball and socket joint that is the hip.
The pelvis and the hip joint bear the weight of the entire upper body. These structures must efficiently transfer the load created by the upper body weight, while at the same time absorbing the forces that are transmitted upward through the legs into the hips and pelvis by the force of the feet striking the ground. To assist in the absorption of these forces, the hip joint contains a small gel-filled sac, known as the iliopsaos bursa. Bursa are a common cushioning feature in other human joints; they are prominent in the structure of the spine, shoulder, and elbow.
Iliopsaos syndrome is the name applied to two distinct but related conditions of the hip joint. Hip injuries generally account for as much as 5% of all sports injuries. The first, iliopsaos bursitis, is caused when the bursa becomes either inflamed or irritated; the second, iliopsaos tendonitis, arises when the fibers of the iliopsaos tendon become inflamed. Tendonitis may be an acute, shorter term ailment, or a chronic condition. In either circumstance, the fibers of the tendon have sustained tiny disruptions to the individual structure of each, known as a micro-tear. Tendonitis may also manifest itself as a related condition of its own, peritendonitis, which is an inflammation of the soft tissues that surround the tendon fiber, without damage occurring to the tendon itself. In many cases, the onset of one of these conditions will cause the other. Both aspects of the syndrome produce similar symptoms, including significant pain localized to the hip joint, stiffness of movement in the hip, coupled with a "cracking" or "popping" sound when movement is attempted that involves the joint.
Participation in a number of different sports may create stresses on the iliopsaos bursa. Various gymnastics routines and track sprinting, which requires repeated and explosive movement from the starting block in a crouched position, are prominent examples of potential iliopsaos stress. Rowing is also an activity that burdens the iliopsaos, through the sliding and resistance motions required. Iliopsaos syndrome may also arise from a significant blunt trauma to the muscle structure, such as a hard tackle in football or rugby. A failure to adequately stretch the iliopsaos and the surrounding hip flexor structures is a common underlying factor in assessing the cause of this condition. There are also training regimes that can contribute to iliopsaos syndrome, particularly repeated hill running and forms of resistance training such as leg presses and squats.
Young athletes are particularly vulnerable to iliopsaos injury. Different aspects of the musculoskeletal system grow during the growth spurts that occur during adolescence. During these periods of growth, the iliopsaos can become inelastic, relative to its adjacent muscle structures. The tightness of the iliopsaos tendon can create a chain reaction into the gluteal muscles and the low back, resulting in an increased curvature of the lower spine, commonly known as lordosis of the spine. The forces placed upon the spine by lordosis directly stress the vertebrae and lumbar disks, all of which create irregularities in the gait of the athlete. The chain reaction that precipitates irregular gait places its own stresses on the lower limbs and joints, with a prime location of injury the patellar (knee) tendon.
The rehabilitation of an iliopsaos injury will start with a rest from the activity that initially caused the injury. As with virtually all soft tissue injuries, the immediate implementation of RICE (rest/ice/compression/elevation) treatment is an important step. Applications of heat, combined with massage therapy, are often useful in the reduction or minimization of the effects of scar tissue. Stretching exercises that place the hip joint, lower back, abdomen, and upper leg muscles through their ranges of motion are critical to iliopsaos health.
As iliopsaos syndrome is often the result of repetitive practices, it is important for athletes to review their previous approaches to warm-up and cool-down protocols, to ensure that the structure is fully stretched.