It is estimated 80% of running injuries are due to overuse. In the most simple terms, running creates stress on the body. If the stress exceeds the body’s capacity the result is often pain.
Runners love to run. It’s a simple yet beautiful activity that does not require much equipment, membership or experience. Through running, our hearts, lungs, bones and joints all get stronger through training. Adaptability to stress is my favorite principle of training and rehab. As long as the workload we place on ourselves is gradual yet consistent, we will become more resilient.
However, most people’s cardiovascular and muscular fitness improves more quickly than the conditioning of their passive structures (cartilage, ligaments, tendons, bone). As a result they are more susceptible to overuse injuries. Through identifying risk factors that may predispose runners to injury, we devise an evidence informed strategy to mitigate injury. These risk factors consist of 4 major categories: lifestyle, training, biomechanics, and running form.
Lifestyle
Lifestyle factors consist of demographics, sleeping, eating, work etc. Most studies note females are more frequently injured than males. Also novice runners and those returning to running after a layoff have a higher likelihood of injury. Age is often associated with injury rates. However, the research is conflicting as to what age group is at risk. Some studies indicate younger runners are more likely to sustain an injury; whereas other studies associate older runners.
As I discussed last month, sleep plays a huge role in how we feel day-to-day, but can also prevent or contribute to injury. Food and sleep are non-negotiable in recovering from intense training programs. The only good training is training which includes recovery.
Training
Training factors are those related to how much, often or frequently we run. The number one risk factor for developing a running injury is having had a previous running related injury. Other than this, there are two other noteworthy training errors associated with injury. Runners who change more than one training variables- velocity, distance or frequency- were more likely to be at risk of injury. Additionally, runners who progressed their mileage by 30% or more for more than one week in a row increased their injury risk.
In real life, most runners will progress their mileage week after week when building base mileage or or preparing for a longer race, like a marathon. The training programs in these observational studies do not mimic real life progressions. These studies often make one increase in mileage or make an average increase in training volume over the course of the training block, which is usually over a 6 to 12 week period. Here is an example of the challenge of applying scientific research to clinic situations. The research evidence can inform practice but does not create absolute rules to govern training programs.
In my practice, I recommend a training plateau following a progression of mileage to provide the body time to adapt to the additional workload. Certain pathologic conditions necessitate this slow progression. For example, shin splint injuries may take up to three weeks to recover from a change in training. In my runners who have bony injuries like shin splints, I advocate for only adding one variable every 2-3 weeks. In the 2-3 weeks the bone will adapt and become stronger from this new stimulus.
Biomechanics
Biomechanics is the study of how we move in space. This pertains to range of movement, alignment or the forces acting on or within us. Unfortunately, research does not give us any black and white recommendations.
Strength, flexibility and alignment risk factors are widely varied and met with multiple conflicting studies in research. For example, in high school runners, strong hip abductors were associated with injury, but the authors did not control for training variables or demographics making the generalizations from the study impossible.
Like strength, range of motion is not strongly associated with injury. In fact, there is evidence suggesting limited hip internal rotation is protective against injury because the tissues are more compliant and the range of motion less exposing to vulnerable structures.
Interestingly navicular drop, aka a flattened foot arch, has been shown to be a protective against injury in some studies. This flies against conventional wisdom (unless you’ve read my other blogs) that pronation is a problem to be addressed in runners.
When it comes to biomechanics, most of us have aspects of our movement that could be enhanced. While it is improbable for us to predict an injury based on biomechanics, addressing weak links in our movement will make us more effective runners and may even reduce our injury risk. Assessing biomechanics should be done on a case by case basis for each runner in the context of their injury history, running form and desire to make changes.
Running Form
Well-known biomechanist Irene Davis has a saying, “runners should land softly and well aligned.” In this statement she is nicely reducing the vast evidence on running form and injury. Running injuries are linked to high ground reaction forces. This is how much force occurs when our feet touch the ground. Higher forces are associated with knee and shin pain.
Additionally, the alignment of our pelvis and femur play a role in running related injuries. Runners with pelvis drop and dynamic knee valgus are gait characteristics associated with injuries. While standing on the right leg, if the pelvis does not maintain a horizontal position then this is considered a pelvis drop. Meanwhile, dynamic knee valgus occurs when the knees almost touch reach other while running. I will sometimes refer to this a a dynamic knock knee.
However scary all these running form issues may seem, they all are effectively treated through simple changes like manipulating cadance, decrease foot strike noise and minimizing bouncing. Check out a my previous blog for more details.
So given what we know, How do runners ward off injuries?
Have a coach, PT or a specific plan. Running is simplistic and that is a part of its appeal. However, too often runner’s get the “disease of more.” They feel good and want to run more miles, workouts, races etc. OR they want to achieve a personal best or complete a certain race distance so they keep pushing themselves. This leads to poor judgement. Having an outside, objective voice to provide recommendations and guidance keeps us training appropriately.
Strength train. Although no studies have been specific to runners; in a systematic review of athletes resistance training was found to reduce overuse injuries by 50%.(https://pubmed.ncbi.nlm.nih.gov/24100287/)
Sleep. Get on a schedule and get it done! Naps can be effective if you are not getting enough rest at night.
If you have an injury history, a physical therapist specializing in runners can help develop a plan focused on strengthening, flexibility, manual therapy as a well as providing a safe and appropriate running plan to keep runners running!
If you are interested in a running assessment or working with a running PT specialist then make the first step: