Runners: I’m sorry, but you’re going to have to move sideways

Written by: Jenn Brooks, Master Trainer

The average injury rate for the recreational runner is between 37% and 56% per year, with 50-70% of those injuries caused by overuse. This is incredibly high. When injuries do occur, the 5 standard medical advice is typically a variation of “stop running until it feels better.” While this generally works quite well at healing the current injury, it is ineffective at preventing future injuries. To break out of the injury cycle, it’s necessary to explore what underlying factors lead to injury and are likely to do so again. In many cases, the primary factor in an overuse injury traces back to an inability to maintain alignment while managing the multiplanar forces that occur while running.

To better understand how to avoid this, it’s necessary to break down the impacts of running. When you run, every step lands with the force of 250% of your body weight; of that impact, forces equal to 25% of your body weight are directed sideways. In additional to lateral and sagittal forces, you also have rotational impacts; though often subtle, these rotational movements play a major role in both energy efficiency and injury. For instance, there is a strong correlation between excessive internal hip rotation and patellafemoral pain.

Put together, this is a tremendous amount of multidirectional force to control on one leg at rapid speed (the average ground contact time for an experienced recreational runner is 200-300ms). Illustrating the importance of force transfer in the gait cycle, analysis has shown that joint torques and EMG activity are both greater as the body prepares to land than at the point of takeoff in each stride. Taking off (stance phase) is relatively straightforward; transitioning a large amount of energy through swing to stance is the true work of running. An inability to make this transfer in a way that is efficient and safe is behind many running injuries.

So, where does this leave you? Running efficiency requires the delicate balance of having enough mobility to avoid compensations down the chain and enough stability to prevent a loss of alignment and momentum. Strength and mobility training play a vital role in preventing injury by enabling the runner to avoid these damaging compensations. There are many tests that can be used to identify faults likely to
cause injury, but one of the easiest places to start is the single leg squat assessment. If you cannot do a single leg bodyweight squat without losing alignment, you almost certainly cannot maintain good alignment while absorbing a sideways force of 25% your body weight. You have some work to do.

Peruse almost any running forum question about strength training, and you will inevitably read a lot of answers that talk about squats, deadlifts, and pullups. These exercises are absolutely good ideas, but they are not the complete picture. Running is a sport that happens one leg at a time. It makes sense that if the goal is to run without injury, it is imperative to train your legs to stabilize and recoil singularly and to
train your body to control and harness forces in all planes of motion. You are going to have to balance, and you are going to have to move sideways. Single leg exercises, lateral movements, counter-rotational exercises, and mobility work all play a vital role in an effective injury prevention routine.

References
1. Dicharry, J. Anatomy for Runners . Skyhorse Publishing: New York,NY; 2012.
2. Novacheck, T. The Biomechanics of Running . Motion Analysis Laboratory. Gillette Childrens Specialty Healthcare, University of Minnesota. 22 September 1997.
3. Running Science. https://www.garmin.com/en-US/runningscience/#ground-contact-time. Accessed February 10 2018.
4. Souza, R.B. and Powers, C.M. Predictors of Hip Internal Rotation During Running. Am J Sports Med 2009 37:579. doi:10.1177/0363546508326711.
5. Van Mechelin, W. Running injuries. A review of the epidemiological literature. Sports Med . 1992 Nov;14(5):320-35. https://www.ncbi.nlm.nih.gov/pubmed/1439399. Accessed February 8, 2018.