Updated: Jan 3, 2022
There's a rumour that has been doing the rounds for quite some time. It goes something along the lines of - "stiffer ankles help with returning force from impact making the rebound more efficient for running and jumping", or some variation of that theme. With many things in the fields of health, fitness and nutrition, there's a lot of nuance, arguments that make sense from both sides, and some grey areas and missed truths in between. Here though, we're pretty certain - ankle range of motion is king!
Firstly, nomenclature varies when it comes to differentiating between flexibility, mobility and range of motion. It's beyond the scope of this article to discuss it, but suffice it to say, the greater the angle between your fully dorsiflexed and fully plantarflexed foot, the better for running efficiency.
With the toes pointed somewhat downwards, we are able to land fore-to-mid-foot and create the absorption chain associated with landing, or the eccentric phase of plyometric loading*. At this stage, we enter the amortisation phase, where we absorb the kinetic energy created by falling, and dissipate that through the chain of muscles involved in deceleration, predominantly in the lower leg. As Zatsiorsky and Kraemer explain in Science and Practice of Strength Training, a muscle that has the ability to change length the most can utilise the most energy stored during this phase on the following concentric phase, or countermovement.
There is a cadence required to efficiently utilise this energy; 170-180 strides per minute. You can read many posts, unfortunately, some from reputable running pages, on social media that make out this cadence prescription is subject to huge individual fluctuation. Whilst there is nothing "wrong" with a slower cadence, it is by definition, less efficient. Plyometric action - plyometric quite literally meaning more length - requires an amortisation phase of <250ms. That means in under 0.25 seconds the change from eccentric [landing] phase to concentric [take-off phase] needs to have been completed. The mathematicians will already have deduced that adds up to 4 strides per second, as opposed to the 3 required for 180spm, but remember this is just the amortisation phase, not the entire stride.
While running, especially over distance, isn't truly plyometric in nature, it certainly follows the stretch-shortening cycle pattern in a similar fashion, albeit with less force intention with each stride. This built-in energy transfer system - think rubber ball bouncing when dropped - can be maximised in an individual using 3 simple strategies:
Practice running at a slightly higher cadence. It may not be 180spm straight away, but work consciously towards it.
Work on both strength and range of motion around the ankle simultaneously. Use a combination of bodyweight and weighted exercises that emphasise a full range of motion, and particularly strengthen the muscles of the calf and shin.
Land with the forefoot or midfoot, with the foot under the body, and pull the foot back off the ground before the rear leg fully extends.
For more tips, keep your eyes on @runstrongprogramme on Instagram. If you use this or any other tips, let me know in the comments how you get on!