By: Dr. Corey Finan – Doctor of Chiropractic
Of course running can result in injury. If you have done any running for any length of time, you have probably come up against this certainty. The most common sites of injury in runners in descending order:
- The Knee
- The Ankle / Foot
- The Lower Leg (Shins)
- Hip / Pelvis
- Achilles / Calves
- Upper Leg
- Low Back
Of those regions, the 10 most common overuse injuries runners can expect to come across are:
- Patellofemoral Pain
- Ilio-Tibial Band Friction Syndrome
- Plantar Fasciitis
- Meniscal Injuries
- Shin Splints
- Patellar Tendinitis
- Achilles Tendinitis
- Gluteal Injuries
- Tibial Stress Fracture
- Spine Injuries
The problem is, most of these injuries are actually OVERUSE injuries! They are very hard to treat because the injury is NOT the problem, it is the result of an underlying mechanical dysfunction. The analogy here is the car with a wheel alignment issue. The wheels are not in proper alignment, and therefore start to groove a wear pattern in the tire that is different from the other tires, and from normal. Over a period of time the wear pattern worsens, until the tire is so warped now that the drive becomes uncomfortable. You check the tire, and see that it is worn in a crazy pattern. However, it is not the tire that is your problem, it is the alignment of the axel that holds the tire in proper alignment. So just replacing the tire will not solve the problem. Just like treating the iliotibial band will NOT correct the problem that led to the symptoms in the first place. Fortunately, there are some common pattern changes that lead to common overuse patterns and therefore common overuse injuries.
We need to introduce a concept here, known as the Overload Principle of tissues. The application of a force over a certain area of tissue during movement results in stress to the tissue. Abnormal stress (type, amount, etc.) to tissue causes it to break down. Stress that is too high, or applied for too long can cause this breakdown as well. Often the cause of injury is simply neglecting to follow the concept that you need to have time for the tissue to adapt to the stress you’re imposing on it, allowing it to strengthen and improve its structure in response. Faulty movement patterns are the #1 cause of abnormal tissue stress.
When it comes to running, you are looking at a series of single limb impacts in a repetitive nature. Basically this means one leg is always falling forward and hitting the ground. When it hits the ground there is a ground reaction force (think Newtonian physics – equal and opposite reaction) which is approximately 2 to 3 times your body weight. In the end, you push about 65-75 bodyweights through your legs and up your spine PER SECOND. This creates a huge demand on muscles, and joints to control and dissipate that force. This is where shock absorption comes into play. Your ability to absorb the shock of hitting the ground is a major contributor to your ability to run without pain.
There are two shock absorption strategies generally acknowledge in the literature. One utilizes more of the gluteal muscles and hip extensors to control the force. This is termed the “Hip Strategy”. The other uses knee extensors, quadriceps and calf muscles to shock absorb, and is called the “Knee Strategy”. The use of the hip strategy leads to better use of the gluteus maximus which then allows the runner to decrease the internal rotation of the femur which leads to less knee inward collapse. The result is less stress on the knee, and less pronation at the foot/ankle.
Often some of the most troubling injuries seen in clinical practice are the result of tightness in the quadriceps muscles. Patellofemoral pain syndrome, patellar tendinitis, meniscal injuries, and achilles tendinitis are all the result of using the knee strategy to shock absorb. This leads to overuse of the wrong muscles for shock absorption, leading to pain over time.
So why do people “choose” to use the knee strategy to shock absorb? I don’t think people choose this strategy, but rather are forced to use it because of weakness elsewhere (such as in the hip extensors, and hip stabilizers). By default your body will select whichever strategy is available to it to absorb the shock, and spare your joints. If it can’t use one, it will choose the other. Thus you start to see injuries as you change your shock absorption strategy. This can be subconsciously controlled, so you don’t even know it’s going on. Avoid these common injuries of running by being informed about how you run.