When I assess injured runners at the clinic, I see a number of common features including excessive and/or prolonged foot pronation, heavy foot strike and over striding, poor knee function, poor hip function, poor pelvic control, and the list goes on. Attempting to change any particular feature of someones running action may help reduce stress on one area, but can increase it in another.
Strike pattern is a great example of this where changing from a heel strike to a forefoot strike will reduce load on the knee and hip, but increase it at the foot and ankle. Therefore, most changes to running mechanics should be done with great care, ensuring that the individual is capable of making the change (e.g. they have the strength and endurance in their foot and calf to change to a forefoot strike).
Increasing cadence
One very simple biomechanical change, which is generally very safe is to increase someone’s cadence (number of steps they take per minute). In fact a reduced cadence compared to an uninjured runner, or the theoretically ideal (170-180), is one of the most common findings in injured runners I treat clinically. I underline ‘theoretically ideal’ because it is exactly that, theoretical. But let’s not start a debate on the magic number for cadence here!
Anecdotally, increasing cadence can reduce pain for almost any running-related injury I see. Unfortunately I have no rigorous clinical trials to support this, but we are working on research in London led by Brad Neal currently – watch this space. Additionally, there are now more than 20 biomechanical studies which can be used to support the potential importance of increasing cadence in an injured runner. I will not go into all in detail, since it will create a novel (not a blog). One very simple study with a lot of good information was published by, Heisderscheit et al[1] in 2011 though. In this study, the biomechanical effects of increasing cadence in 45 healthy recreational runners was evaluated. With an increase of 10% in cadence, the following was reported to occur (represented graphically in the Figure):
Figure Different loads on the hip, knee and ankle whilst running with varied cadence
The findings above indicate increasing cadence by 10% may reduce loads on the knee and hip during running significantly, and this may have important therapeutic effects. In fact energy absorbed at the knee was reduced by 34% when cadence was increased by 10%. Most importantly, there were no associated increases to loads at the foot and ankle which is commonly seen when changing from a rearfoot to forefoot strike.
Considering these findings (and many others in the cadence literature), it is clear that increasing cadence may be a potential therapeutic running retraining change in many injured runners. Importantly, cadence is easily assessed and manipulated and requires no complicated biomechanical assessment. A runner can simply count the number of steps per minute they take. Then, to manipulate, use a metronome, songs with the desired beats per minute, or simple instruction to “take shorter faster steps.” Optimal running retraining to manage running injuries is obviously far more complicated than this, but increasing cadence is a safe and effective starting point for any injured runner.
References
1. Heiderscheit BC, Chumanov ES, Michalski MP, et al. Effects of step rate manipulation on joint mechanics during running. Med Sci Sports Exerc 2011;43(2):296-302
