Hip flexors help provide flexibility in the hip and stability for the leg. Pain with hip flexion is often associated with sudden movements and injury during sporting events. Some of the causes of pain when the hip is moved include acute trauma, strains, and compensating for other injuries.
Three muscles make up the hip flexors: the rectus femoris, illiacus, and psoas major. In addition to providing movement of the hip, the rectus femoris, a quadriceps muscle, also helps with extending the knee. The illiacus muscle, which originates from the lower spine, and psoas major muscle run across the pelvis to the head of the femur. Injury to any of these muscles can lead to pain when the leg is moved at the hip, and discomfort is typically experienced along the front of the hip and thigh. In addition to pain, patients may also notice difficulty with movement and muscle spasms.
Trauma, such as from an accident, fall, or sudden movement, can cause damage to the hip flexors and cause pain. This can occur when an athlete makes a quick or sudden movement in one direction, for example, such as when a soccer player makes a sharp cut with the ball in the opposite direction. The action can cause the hip flexors to be pulled or strained, resulting in injury and pain.
Strains in these muscles can lead to pain when the foot is lifted and/or the knee is pulled toward the chest, as if taking a step. These strains can range from first to third degree. First degree strains typically are minor, second degree strains may result in a muscle tear, and third degree strains cause a complete tear of one of the hip flexor muscles. Athletes or others may often try to continue their normal activity even with a first degree strain, which can cause further damage.
Compensating for other injuries or lack of strength can also cause damage to the hip flexors, leading to pain with hip flexion. This includes strains due to lack of strength in back and abdominal muscles that help stabilize the hip. Injuries to the quadriceps, specifically the rectus femoris muscle, can also lead to further strain on the hip muscles.
Recovering from hip flexor injury and pain usually just requires time and home treatment. Ice and over-the-counter anti-inflammatory medications can help with pain and any swelling. Qualified physical therapists, athletic trainers, or strength and conditioning coaches can also help develop an exercise and stretching plan to help recover from hip flexor injury and reduce the chances that it will happen again.