Why Do Runners Get Injured?
Most running injuries occur as a result of the runner possessing multiple risk factors and then participating in running over prolonged periods. Risk factors include inexperience, excessive training duration and/or intensity over long periods, low focus on recovery, decreased ankle mobility and decreased strength. Injury-prone running typically occurs under certain circumstances where the structure's (tissues i.e muscle, bone, ligament ect.) load capacity is exceeded by the forces placed on them long enough for the tissue to break down, gradually, during the duration of the run.
Experience and Load
Less than two years experience with running is associated with greater risk of running injuries. This may be due to decreased knowledge on running mechanics, frequency and intensity prescription and, often, trying to do too much too soon. Many newer runners want to push it every day. Continuing to perform at a peak intensity level for every run or even every other run is a recipe for injury. This can be formally addressed by planning individual runs and understanding how to plan and schedule runs for the coming days, weeks and months. Instead of constantly running at high intensities we want to work on different methods of training. Training load equals the duration of the run multiplied by the intensity of the run. A majority of running injuries are caused because runners are running too fast, for too long and doing those too early. When planning a run they should all be intentional, with a certain goal in mind. Research says that most of the time people run at excessive intensities and that 80% of runs should be at lower intensities paired with greater duration. During the 20% of runs at higher intensities runners should work at higher speeds with shorter durations and even interval training. As running efficiency and capacity improves, runners will have increased structural load acceptance and will be able to generate greater output leading to improved performance and decreased risk of injury.
Running capacity is the overall ability of local tissues, but also the whole system, to tolerate a certain amount of activity. The system (the full body) would be responsible for all of our expendable energy to be used during running. Within this system for running is mobility, strength, and cardio-pulmonary function amongst other things. Then there's the engine that drives the movement. Within that scope of general movement there's experience, efficiency, alignment, load acceptance and understanding the course. A physical therapist’s goals are to maximize the movement efficiency through gait training and correcting muscle imbalances and set the runner up so that structurally they're strong enough, mobile enough and have the knowledge and experience to run properly.
In regards to mobility, our goal is to attain a range of motion that promotes proper load acceptance on all structures primarily involved in running particularly in the toes, feet, and ankle but also the knees and hips. Impairments in mobility, and range of motion, can disperse an overload of force onto improper structures. For example, if there is decreased range of motion at the ankle, the knees, hips and lower back will receive additional load to compensate. Forces can also be distributed to more local structures like the achilles tendon, thus increasing the load capacity needed by that tissue and increasing the athletes risk of injury.
Strength training is extremely important in running athletes, and it's often undervalued. It is a common misconception that because they are running, and they may have toned leg muscles, they assume they are strong. This is not true. The literature essentially shows that running doesn't do much for strength but rather builds the endurance aspect of muscles. Weight training and heavier resistance strengthening of the glutes, hamstrings, core and quads will reduce the risk of injury for all runners. Strengthening for runners should be performed both in and out of the sagittal plane of motion ( example: lunges-sagittal plane, and lateral lunges-frontal plane).
Tissue Capacity and Stiffness
Tissue capacity and stiffness are terms used to describe the amount of stress that muscles tendons and ligaments can endure. Sufficient tissue stiffness is needed for performance and can be adjusted through manipulating footwear, running surfaces, and also through consciously altering running pattern and mechanics to change the forces that the body experiences. An example of conscious changes would be actively thinking about changing your landing from throwing your midfoot into the ground but switching to intentionally landing soft on the toes or increasing running cadence that require shorter less forceful steps. The perfect recipe for the lower extremity is to decrease ankle stiffness, and increase knee stiffness to increase running economy. So basically, ankle mobility is important to improve and then we want to improve knee strength as well to promote that stiffness and to optimize recovery. Failing to recover properly is another reason why our runners are getting injured and through this you can use assistive modalities like foam rolling, Normatec and stress the importance of sleep. For runners, the most important factors in our recovery include aspects that we can control like hydration, sleep, and nutrition.
Co-Authored by DPT candidate Tim Reilly and Nicholas Petroski DPT.