Elastic Recoil, Free Energy for your Running stride…read on
I recently attended a presentation by Dr Wilbour Kelsick, titled “Fascia Principles in Running Sports” and I just wanted to share some of his ideas as I feel there are some key tips to think about and I hope will be of interest to you. I certainly feel they will help me with my running and training.
First let’s look at a definition of the word “fascia”, which is very topical in my world at the moment. Fascia is defined as “a sheath, a sheet or any number of other dissectible aggregations of connective tissue that form beneath the skin to attach, enclose and separate muscles and other internal organs.” (Stecco 2015)
Importantly for us it is believed (as this is still very new thinking) that fascia influences and aids all our body’s movements, through tension and compression throughout the whole body, rather than singling out individual muscle contractions for individual body actions.
So coming back to running and fascia. Running itself is a hop, flight and hop movement. When we walk we go through something on the ground, but when we are running we are stepping over something and so at some point we are in the air floating (both feet off the ground). To achieve this floating Dr Kelsick describes this as “running elastically”, creating the right amount of tension and compression for the elastic recoil of fascia to bounce us forward in the air.
Fascia has the ability to temporarily store energy and return it quickly for use, giving us this bounce, which we can see in cyclic movements, such as running and cycling, and it is the same as we see in explosive rhythmic running in animals such i.e. gazelles or cheetahs. Running elastically uses less energy, and less muscular power, and so importantly it helps prevent typical overuse running injuries.
So how do we “run elastically”? For ease of understanding I am going to focus on one key point and this is the importance of the positioning and flexibility of the ankle and the foot, or more precisely the arch of the foot and the Achilles tendon, for the foot strike phase of running.
In order to achieve elastic recoil from the arch and the Achilles tendon the ankle needs to be dorsiflexed (which means bringing your toes slightly to your nose) for landing. In dorsiflexion the subtalar joint (the joint between the ankle and the start of the foot) locks therefore upon foot strike there is less stress through the body. The impact force from this foot strike stretches your Achilles tendon and all the fascia of the arch of the foot (which includes the lower leg and toe tendons which run and insert on the sole of the foot) and this force is momentarily stored as elastic energy.
Upon landing the Achilles reaches its maximum safe stretch and your stretch reflex causes your calf muscles to contract to start the propulsive take off stage of running. So for take off the foot rocks from heel to toes and the ankle starts to plantarflex (the foot points into the ground) and as this muscular contraction happens simultaneously the arch of the foot releases its stored elastic
energy, which has be shown to create 17% (1) of forward force, and the Achilles tendon then releases its stored energy, which has been shown to create 25% (1) of forward force, and we are propelled forward to float through the air!
This is the fascia’s elastic recoil creating the push or bounce forward adding to the force generated by our muscles. The stronger the release of this recoil the less time the foot is on the ground and the body is moving freely forward in the air! This is free energy created by the impact force from each foot strike and it is captured, stored and released by the fascia.
It is important to remember that fascia and tendons are the major recoil force and the stiffer you are the more energy it takes to stretch them so keeping all our soft tissues supple and flexible eases our movement and the amount of energy it takes us to move!!
Please note, this article is intended as brief explanation about the importance of the foot strike in running sports and how it can help us become more effective and efficient runners, it is not a set of running instructions. It is something for you to think about.
The next thing of course is to keep this in mind while training and Dr Kelsick shared some ideas on this so please ask me if you want to discuss, or if you have any specific questions. firstname.lastname@example.org .
(1) Dr Wilbour Kelsick Presentation, 26th June, Bank House Hotel, Worcester.