This guest blog was written by Adarian Barr, Assistant Track Coach, Jump/Hurdles/Multi-events at the University of North Carolina in Pembroke.
To read Adarian’s past articles, click here as well as my Freelap Friday Five with him.
In track and field we deal with the theories of stride length plus frequency and force application in order to run or sprint faster; this is something everyone agrees on. The issue is how to implement those theories.
Several questions arise, such as; which comes first, stride length or turnover? How do we apply more force? What do we apply the force to? What about ground contact time? How do we apply more force without increasing ground contact time? How do we reduce ground contact time without shortening stride length? Do we need to get stronger to apply more force? How much stronger and stronger at what? It goes on and on.
The one thing that is tried and true is that force is mass x acceleration. A problem that arises is the misunderstanding of which mass to accelerate. Therefore, when applying the above mentioned theories, we often deal with the wrong mass. We increase turnover to move the torso faster or we apply more force to the ground to create a higher impulse to accelerate the body or drive the hips forward.
We often also are not clear on the terminology. Turnover, stride length, frequency, and so on.
First, terminology clarification; frequency does not mean turnover.
Frequency is just the number of times your feet touch the ground. A slower athlete will have a higher frequency. If an athlete wants to take fewer steps or strides, they tend to want to increase frequency. By doing this, they do the opposite as they tend to decrease their stride length which makes them run slower.
Turnover rate is the speed at which your feet leave the ground and get back down to the ground. All the science says that all runners and sprinters have the same turnover rate. A Usain bolt doesn’t move his feet any faster than would the average sprinter but often we try and increase our turnover to sprint or run faster which once again reduces stride length and causes one to run slower not faster.
In order to increase my stride length I have to apply more force, but not by pushing. The athlete is instructed to push the ground away, and at the same time tell them to pick
the foot up and put it back down as fast as possible. This is where backside and front side actions, not mechanics, come into play.
The one true statement that we should always keep in my mind is that force is equal to mass times acceleration. Backside action is the acceleration portion of the equation. The leg is the mass which is connected to the foot; therefore, the foot is the other mass we are trying to accelerate besides the arms.
The difference between backside actions versus backside mechanics is that you are dealing with intent versus what just happens or a passive movement.
Now backside is just that; what happens on the posterior side of the body. What happens behind the body with the leg as it goes from support phase to recovery phase, a person walks, sprints, runs or jogs.
Everyone has something backside, whether it is actions or mechanics depends on the intent of the athlete.
Some athletes may have a natural backside action while others may not. Those who don’t have backside action can be taught it and those that have natural backside actions can improve upon it.
The backside action is the intentional act of knee flexion through the use of the calf muscle instead of the hamstring or momentum. It is important to understand this concept as the importance will become clearer on front side mechanics and additionally with the understanding of force application.
How to start running or sprinting, backside action
To start running or sprinting the first thing to do is create instability; the greater the instability the greater the force that will be produce by the support leg.
Most athletes create instability by leaning forward. The one problem is that you are still very stable. So at best you take a small step forward to become stable again. The reason for the small step is the expectation of instability. The body is prep to be unstable and reacts accordingly.
To create the suddenness of instability you need to use the calf muscles to create knee flexion in one of the legs.
To create instability gradually by lifting a foot off the ground does not produce a great enough force from the support leg for high impulse.
Front side action
Front side action is a result of backside action.
Front side action has an impact on stride length and the speed at which the foot hits the ground. Which impacts force application and stride length.
The straighter the leg the greater the stride length, the faster the leg moves the shorter the ground contact time will be.
With the calf muscle freeing up the hamstring to work with the quad muscle to create leg extension thus allowing for complete leg extension on the front side, along with reducing the braking action from the leg and hip moving in same direction instead of opposite directions which will reduced the athlete’s ground contact time.
Step over drive down is a common cue given to sprinters with no real instructions on how to create the action. With proper backside action the step over phase which is the transition from backside to front side happens automatically. The issue to is that it should be called pass by.
The step over happens when the ankle of the recovery leg passes over the knee of the support leg when viewed from a side angle. The ankle should clearly pass over the top of the knee if the athlete is sprinting and slide by the knee if running.
The drive down phase should be call push the foot away from the body. As you want to project your foot in the direction of hip travel.
This will allow for fast leg extension and high foot speed at ground contact.
It also allows for the foot and hip to travel in the same direction along with allowing the athlete to land on the ball of the foot and keep the heel off the ground.
In reality the athlete should make initial ground contact with his fifth metatarsal.
Something that is not often talk about is under striding. Bud Winters thought that most athletes never fully develop their stride length to optimal capabilities.
So the issue is that most athletes are most likely under striding and not over striding.
Braking action, you need a braking action when the foot contacts the ground. That is why we have friction which is a force.
What happens to most athletes is that the foot is slowing down because the hamstring is decelerating the lower leg as it approaches the ground as oppose to be accelerated towards the ground.
Backside plus front side actions
To have optimal stride length you need the combination of back side and front side actions.
Some people can run or sprint well with either but you reach you true speed potential you need the combination of both actions.
Back side sets up the front side and front side helps maintain back side action.
The speed at which both happen contribute to stride length, reduce ground contact time, high hips and tall running or sprinting posture.
The most important factor in improving back side and front side action is hip mobility.
I use PALO hip series with all of my athletes. It has proven to be the one hip series exercise that really gets the hips nice and loose.
It also will increase the speed at which the legs turnover along with increasing the athlete’s strides length.
This is an exercise that my athletes perform every day.
Starting and reaction
Back side action should be the what of what to do when you hear the b of the bang.
Closing the gap between the calf and hamstring should by the primary concern of the athlete.
Working off of the fifth metatarsal from the blocks or sprint stance is the easiest way to create or initiate backside action.
The back side action creates a sudden instability which creates a positive chain reaction.
The biggest plus is it sets up stride length from the start of the race. It also addresses issues like block clearance, high impulse and leg speed. All while using less energy.
Backside action is the key to force application, reduce ground contact time, increasing your stride length.
The better your back side action the better the front side will be, the faster you will run.
Backside action is not the same as backside mechanics where the action of the swing leg or recovery leg is passive. Backside action the movement of the swing leg or recovery leg is intentional.
About the Author
Adarian Barr is the Assistant Track Coach, Jump/Hurdles/Multi-events at the University of North Carolina in Pembroke. He is also Movement Specialist and Track & Field coach with Next Level Athletics and Fitness, as well as the inventor of PALO.
Leave a Reply