PROPER LOWER BODY BIOMECHANICS FOR DISTANCE RUNNERS
While there is a school of thought that a runner will naturally do what is right for their body with regard to biomechanics, that is not always true, and in some cases is more likely to lead to injury than not. Just as there is proper form that will provide the most efficiency and success in throwing, swimming, diving or any other movement, for most individuals, proper running technique must be learned.
Rather than begin with the foot strike, let's start with the back part of the motion as this is where mistakes happen that can't be corrected afterwards. In order for the foot to come back in a proper motion once it leaves the ground, the upper body must also be in a proper position. If the runner is leaning forward too much (see above photo), the motion and pattern the foot follows will be an elongated elliptical path that will make for a longer radius. To simplify, it takes longer for the foot to travel that path. However, if the upper body is more vertical, then when the foot leaves the ground, it can cycle up straight towards the gluteal muscles (the butt) in a much shorter time due to the shorter radius. Another piece of the puzzle that allows for a shorter radius and thus a quicker cycle is dorsi-flexing the foot (toes pointing up). As soon as the foot leaves the ground, the foot should dorsi-flex and then cycle up towards the butt. The faster the runner is going the closer to the butt the heel should be. When on a recovery run the heel may only come up about knee level. When racing the Mile the heel should maybe be within 12” of the butt at the top of the cycle. There will certainly be individual variance due to lower and upper leg length differences (levers), but generally speaking the higher the heel in the back the easier it will be to get the most out of the foot strike.
In addition, if the foot does not reach a height close to the butt, in order to bring the foot through to the front, a runner must use their quadricep and hip flexor muscles to bring it forward. If the foot does reach a level close to the butt in the back, then gravity assists in bringing the foot down and to the front. This is not only more efficient, but the higher the foot in the back, the higher the foot will be coming through to the front without having to use additional muscle activity (energy) to get the foot in that optimal position. Again, to keep the radius short, thus a faster motion, the foot should stay dorsi-flexed. An additional benefit of having the foot dorsi-flexed is that motion stretches the calf. It is a fact that a longer muscle can contract with greater force. Thus, elongating the calf muscle by having it pre-stretched prior to landing will allow the runner to push off with greater force.
So, what is the benefit of the foot being at or around knee level as it comes through to the front? First, I will explain what many runners do, which is not getting their heel up high in the back. They must use their quads and hip flexors to bring the foot to the front and even greater energy to raise the foot up close to knee level. Most of these runners do not have the strength to do this, so the foot comes through at a low level. Since it is already closer to the ground there is not enough time to bring the foot all the way through to get a proper foot strike. Many of these runners end up heel striking or at best landing flat footed.
If the heel is high in the back and the foot dorsi-flexed, the foot can come through at a higher level without using additional energy. It is ideal to land slightly in front of your center of mass so that there is a small amount of pulling action as well as the resulting pushing action as the foot rolls through ground contact. To get the most out of foot-strike the foot should land towards the outside of the foot at mid-foot position (The faster a person runs the closer the foot should land in line with the center of the body. In order for this to happen the foot must supinate, thus allowing the foot to land more on the outside of the foot). As the foot passes under the center of mass it should roll across towards the center and front of the foot, which optimizes push off on the toes as the foot leaves the ground after the body has moved forward.
Another part of the cycle to pay attention to is how far forward the foot is brought through to the front. While it is ideal to have the toe pass in front of the knee, which allows for greater dorsi-flexion as well as time for the foot to supinate for proper foot-strike, the runner does not want the heel to pass in front of the knee. This causes unnecessary motion and time, uses more energy bringing the foot back to the ground and worse, can lead to heel strike. Heel strike is very jarring to the body, decelerates the body and could potentially lead to stress reactions.
