Can you run faster AND easier? Yes you can, by improving your running economy.
What is Running economy?
Running economy is about how efficiently you run. A runner that uses less oxygen to run at a certain pace is said to be more economical or efficient.
One method to improve running economy is to minimise energy loss; by releasing stored potential energy to help propel your body forward.
Your body have several such potential energy stores that may not be fully utilised. To minimise energy wastage, you should make full use of
- your Achilles tendon as a trampoline,
- your core muscles as a winding mechanism,
- your legs as a pendulum and
- your body’s flight trajectory like the flight of a javelin.
Bouncing on a trampoline pushes the body upwards via the stored potential energy from the elastic fabric. If the trampoline is too soft or elastic, you will not get a good bounce up because energy is lost by the shock absorbing effect of a soft surface. If the trampoline is too stiff or inelastic, a lot of impact forces go through the legs and body, you also will not get a good bounce and put yourself at a higher risk of impact injuries. Once you “catch” the rhythm of bouncing on the trampoline, it is almost effortless to remain bouncing. This rhythm is known as the resonant frequency, a phase where stored potential energy is easily transferred to kinetic energy with no loss of energy. In reality, there will be some loss of energy and the key is to minimise this loss.
Our Achilles tendon stores energy and transfers it to push the foot off via a stretch-shorten cycle similar to a trampoline. Like the trampoline, the Achilles tendon should not be too flexible or there will be too much dampening or shock absorption. In addition, the calf muscles should be strong enough to stiffen the Achilles tendon and withstand the impact of landing on the foot; at the same time, pushing off with the recycled energy.
Imagine wringing a thick elastic band in a clockwise direction and then releasing it. The elastic band will unwind in the opposite direction and then get wound up again before unwinding again. The rotation and counter rotation will carry on until all the energy is lost. The core muscles of our trunk act just like this elastic band as they wind up to store energy, and release it by unwinding and rotating the trunk in the opposite direction. Unwinding of a "wound" up set of core muscles is easier if the core muscles is stiff, like a stiff spring coil. In contrast, a soft coil of rope doesn't explosively uncoil when released. This trunk winding-unwinding movement helps swing your pelvis forward, making it easier to take longer strides, covering longer distances with each same step.
As your foot swings in mid air during the flight phase, it acts like a pendulum to swing the foot further forward. Ideally, the leg should not go pass beyond the horizontal. If your foot is kicked up higher pass the horizontal, the pendulum effect will not be as effective because of energy lost. The foot tends to go higher either because of your running style or tight hamstrings.
A common running fault often observed is where the body moves excessively in the vertical plane, thus not maximising energy moving forward in the horizontal plane instead. Like a javelin thrown too high, it covers a long travel distance but doesn't travel very far forward..
Have someone look at your running technique and look out for the above faults. Stretch your hamstrings (hypelink to article) and strengthen your core and calf muscles to run faster with less effort.