Running is like any sport in that improvement is dependent on conditioning and training. But it’s about building on your individual running style, not relying on a style or training regime that works for somebody else.
Having an understanding of the biomechanics of running can help you appreciate your own running form and see where you may be able to make improvements. It can also help you make more sense of what you read and hear with regards to running styles, training programs, conditioning exercises, footwear and so on.
Running is a whole body interaction, but dividing the running stride up into individual components or phases can help understand how slight changes can help improve performance and reduce susceptibility to injury.
Breaking down the components of running
The gait cycle starts when one foot makes contact with the ground, and ends when that same foot makes contact with the ground again.
It can be divided up into two main phases – the stance phase (during which the foot is in contact with the ground) and the swing phase (during which the foot is not in contact with the ground).
The Stance Phase
This can be divided into four stages: initial contact, braking (absorption), mid-stance, and propulsion.
Initial contact
The moment in your stride when both feet are off the floor is known as the float phase. Your left leg is out in front of you and about to touch the ground. This moment is called initial contact and is the beginning of the stance phase. Your right foot behind you is off the floor and in swing phase.
Braking
As soon as your left foot makes contact with the ground in front of you, your body is in effect performing a controlled landing, managed via deceleration and braking. Your left knee and ankle bend and the left foot rolls inward to absorb impact forces. During this process of absorption, the tendons and connective tissue within the muscles store elastic energy for use later in the propulsion phase.
Mid-stance
The braking phase above continues until the left leg is directly under the hips taking maximum load as the body weight passes over it. The left ankle and knee are at maximum flexion (or bending) angle. This moment is called mid-stance or also known as the single support phase.
Propulsion
Now that your left leg has made a controlled landing and absorbed as much energy as it’s going to get, it starts to propel you forwards. This is achieved by your left ankle, knee and hip all extending to push the body up and forwards, using the elastic energy stored during the braking phase above. The more elastic energy available at this stage, the less your body has to use the muscles.
The propulsion phase ends when the toe of your left foot (now behind you) leaves the ground, commonly referred to as toe off. At this point, both of your feet are off the ground so you are once again in float phase.
The Swing Phase
At the moment of toe off, your left leg has travelled as far back as its going to and the heel starts to lift towards your backside. The height the heel reaches and the returning drive of the knee is dependent on the power of hip extension achieved, and will hence be greater at higher speeds.
This is a stretch reflex mechanism and can be compared to the stretching back of a sling shot and then letting go. Extension of the hip (as your back leg moves behind you prior to toe off) is equivalent to pulling back on the sling shot.
Letting go results in the leg firing forwards rapidly, leading with the knee. Once the knee has passed under the hips, the lower leg unfolds in preparation once again for initial contact, marking the end of the swing phase.
Upper body and arm mechanics
The interaction between the upper and lower body plays a vital role in running. The upper body and arm act to balance and improve the efficiency of the movement. This balance is achieved by the arms and upper body effectively working in the opposite direction to the legs. Bringing the left arm forward opposes the forward drive of the right leg, and vice versa.
During the braking stage described above the arms and upper body produce a propulsive force. During the propulsion stage, the arms and upper body produce a braking force.
By working as opposites, forward momentum is maintained. The arms and upper body also counterbalance rotation through the torso. For example, as the right knee is fired through in front of the body (right swing phase) an anticlockwise momentum is created. To counterbalance this, the left arm and shoulder move forwards to create a clockwise momentum to reduce rotational forces. There various phases of running, if you have pain while running, one or many of these may be contributing.
If you would like a running assessment, have been experiencing pain when running or would like to start running but you aren’t sure when or how to start, book in to see a Physiotherapist or Exercise Physiologist at Back in Motion Aspendale Gardens by calling 9580 1985 or online.