Having knowledge of the biomechanics of distance running or proper running form will help a runner complete a race more efficiently and lower the risk of getting injury. This guide will cover some of the more important aspects of it.
One of the common mistake that recreational runners make is to treat running like walking where they land the foot with the heel first. By landing with the heel first, the foot will be in front of the body's centre of gravity which will increase the amount of braking force produced, leading to inefficiency. Additionally, when landing heel first, the knee of the landing leg is extended. This will not allow the leg to absorb impact efficiently and will increase the chance of injuring the ankle and knee.
But why is it alright to land heel first while walking? It is because when we walk, both feet are on the ground during heel strike phase. The hind leg is still supporting the body when the front foot lands. Therefore, less impact on the front leg. However, when we run, the hind leg will be in the air which leads to the front leg absorbing all the impact
The more efficient foot strike is to land near the ball of the foot with the foot flat on the ground. This reduce the amount of braking force produced and all the impact to spread out more evenly throughout the foot. Knee will be slightly flexed when landing this way, thus allowing the thigh muscle to absorb the impact more efficiently.
In order to avoid landing heel first, runners should avoid lifting their knees too high and causing a long strike length. Instead, runners should focus on driving the knee forward instead of upwards, to prevent over striding. This will also allow the foot to land right below or near to the body's centre of gravity, so you'll be able to land with the foot flat on the ground.
Another problem that might occur with a high knee lift is the production of too much vertical force (upward movement). This is a waste of energy and causes increased impact. Runners should focus on producing horizontal force (forward movement). One of the method is to focus on driving the knee forward and preventing overstriding.
It is quite common to see people running with a hunched back or a very upright body. Running with a hunched back will decrease the spine's ability to absorb impact and also increase the chances of getting stitches. Running with a very upright body increases the chance of over striding and heel strike, thus, reducing efficiency.
What runners should do is keep the back at it's natural curvature while leaning forward slightly, not too much lean. The slight forward lean will cause the body's centre of gravity to be shifted forward a little. This will allow the foot to land below the body's centre of gravity. It will also help to prevent excessive vertical force production, thus increasing running economy.
While running, we swing our arms to provide balance by countering the force produced by the legs. Without the arm swing, we might just be running in circles at the same spot. To have an efficient arm swing, runners should keep the shoulders relaxed, elbows close to the body and flexed at about 90 degree angle. Avoid swinging the arms across the chest and hands above shoulder height. Keep the hands relaxed as well, as tightly clenched fists can lead to stiff shoulders. Keep the arm swing compact as a vigorous arm swing can lead to over striding.