Movement is Medicine: Hamstring Injuries
“I pulled my hamstring” is an all too often type of injury that occurs in sports. Hamstring injuries account for approximately 37 percent of muscle injuries and recovery is often long with a high relapse rate within the first two weeks of returning to sport or activity.
Injuries to the hamstring occur in the general population, however, there is limited information about how many injuries occur, and how they occur. We do know that the mean age of hamstring injury in non-sporting patients is 49.5 versus 28.7 years in sport related injuries. Women are more susceptible to non-sporting injuries than males.
The proportion of avulsion injuries (tendon pulls off the bone) is more common in non-sporting group and more common in younger and older patients which is consistent with the possible association with bone maturity and bone mineral density.
The hamstrings are a group of three muscles that attach to the pelvis and below the knee. Their action is to bend the knee and to also slow down the knee or hip when one or the other, or both, rapidly contract. The injuries typically occur with rapid acceleration/deceleration when the hip is bent and the knee is straight. Non-sporting injuries usually result from high impact trauma, slips, trips, and falls.
In general there are three types of hamstring injuries:
- Acute injuries in the muscle belly graded I-III with III causing the most tissue damage.
- Grade IV injury occurs when the tendon pulls off of its attachment and is referred to an avulsion. If a fragment of bone is pulled off with the tendon then it is referred to as an avulsion fracture. These injuries typically require surgery.
- Acute or Chronic hamstring tendinopathy. There are two types of tendinopathy: tendinitis and tendinosis. Tendinitis can be acute or chronic and it involves inflammation of the tendon. In contrast, tendinosis is a change in the structure of the tendon that has occurred over time with repetitive micro-traumas or failure of the tissue to completely heal following a previous strain or rupture.
The goal of recovery from a hamstring injury is to return the patient to their pre-activity levels. In the initial stages we focus on minimizing pain, swelling, and scar tissue. Range of motion is introduced within pain free ranges. It is important that the clinician also look at pelvis and hip mobility and apply joint mobilization as appropriate. A study by Cibulka et. al. demonstrated gains in torque of the muscles and faster return to sport when hip and pelvic mobilizations were included as part of hamstring rehabilitation.
Exercises are progressively added as the hamstring recovers. More current research is recommending eccentric (lengthening) exercises with the hamstrings in a lengthened position. Core, balance, and progressive agility training protocols have shown to reduce the re-injury rate to 7.7 percent versus 12-63 percent.
The most challenging question we face as treating clinicians is “when” to return our patient back to activity. Most clinics are using criteria based protocols. These protocols are set up such that the patient can only move to the next level of rehab when they meet certain criteria. In addition to criteria based protocol, we apply a simple clinical test (Askling H-test) prior to returning a patient to full activity. This test assesses whether the patient feels secure or insecure about the hamstring. If they feel secure then they are ready return to activity.
As the old saying goes, an ounce of prevention is better than a pound of cure. If you are participating in sports or activities that require quick movements, be sure to warm-up and gently gain good length in your muscles before you start. If you experience a hamstring injury start treatment immediately. Let a physical therapist guide you through a criteria based protocol so that you can return to play as quickly as possible and without re-injury.
