I decided to tackle this topic after a heated discussion with a former CI of mine on a patient I was treating at the time. During her course of treatment, I had her run on a treadmill to assess her running (at this point she was completely symptom free). I noticed that she had what would be considered faulty running mechanics and based solely on her running gait, my CI suggested that she should not run (even though she was completely symptom free). I disagreed and advised that she utilize a return to running program while still seeing us to address the potential causes of her faulty mechanics.
My argument is that while faulty running mechanics may predispose a runner to injury, we cannot with any certainty assume that they automatically cause injury. Based on running research, the evidence points to what I like to call ‘too much, too fast, too soon’ or training error as the main cause of running-related injuries. It could be one of these variables or the combination of more than one these variables that leads to running injury. You’ll also see below that certain running-related injuries are associated with certain variables. In addition, it is also important to point out that training error has the potential to be affected by other risk factors such as BMI and previous injury as demonstrated by Malisoux et al. 2015 and Nielsen et al. 2013.
This refers to an increase in training volume or ‘session volume’ (i.e. the amount of running performed in a given period of time). In the runner’s case this is the training distance or mileage. Running duration would also be considered training volume as it is still measured as how much running is occurring for a given period of time. As a general rule, it is suggested that running mileage be increased at no more than 10% per week. Click HERE for a nice patient perspective from JOSPT on increasing running mileage.
Nielsen et al. 2013 looked at certain types of running-related injuries that occur as a result of excessive training distance and suggested a correlation between distance and patellofemoral pain, IT band syndrome, and patellar tendinopathy. Nielsen et al. 2014 adds to the list medial tibial stress syndrome, gluteus medius injury, greater trochanteric bursitis, and injury to tensor fascia latae. Nielsen et al. 2014 also demonstrates an increased risk in these distance-related injuries second to a progression in running distance of greater than 30% per week.
This refers to an increase in training intensity also known as running pace, which is often measured in minutes/mile. So if you run a 5K in 25 minutes that equates to a pace of roughly 8:30 minutes/mile. It is important to point out that pace is volume dependent. And we already know that increased volume can lead to injury, so you can see how if you increased both your running distance and your pace at the same time that it could be potentially even more problematic.
Nielsen et al. 2013 also looked at running-related injuries that occur as a result of increased pace and suggested a correlation between pace and achilles tendinopathy, calf injuries, plantar fasciitis. Nielsen et al. 2014 added to that list tibial stress fracture, hamstring injuries, and iliopsoas injuries.
This refers to the frequency that the training is occurring, usually measured at days/week. Let’s say you decide to run everyday without any rest days, do you think that injury is more likely to occur versus running maybe 4 or 5 days per week? The answer is YES! A systematic review by Nielsen et al. 2012 demonstrated that individuals running 6-7 days per week had the highest risk of injury.
In summary, the body needs time to adapt to the stress/load being placed on it. If the training load exceeds the body tissue’s ability to adapt, then injury occurs. It is important to point out that running experience and fitness level play a role as well. A runner with more experience and/or a higher fitness level will be able to adapt to a greater load versus a runner with less experience or a lower fitness level. For more information on training load and tissue capacity I highly recommend reading this article by Tom Goom aka The Running Physio.
Malisoux L, Nielsen RO, Urhausen A, Theisen D. A step towards understanding the mechanisms of running-related injuries. J Sci Med Sport. 2015;18(5):523-8.
Nielsen RO, Buist I, Parner ET, et al. Predictors of Running-Related Injuries Among 930 Novice Runners: A 1-Year Prospective Follow-up Study. Orthop J Sports Med. 2013;1(1):2325967113487316.
Nielsen RO, Nohr EA, Rasmussen S, Sørensen H. Classifying running-related injuries based upon etiology, with emphasis on volume and pace. Int J Sports Phys Ther. 2013;8(2):172-9.
Nielsen RØ, Parner ET, Nohr EA, Sørensen H, Lind M, Rasmussen S. Excessive progression in weekly running distance and risk of running-related injuries: an association which varies according to type of injury. J Orthop Sports Phys Ther. 2014;44(10):739-47.
Nielsen RO, Buist I, Sørensen H, Lind M, Rasmussen S. Training errors and running related injuries: a systematic review. Int J Sports Phys Ther. 2012;7(1):58-75.