Speed & Agility Training Zone!

The Basic Science of Speed Training

By Bill Parisi, C.S.C.S
Founder, Parisi Speed School

Back in the early 1990’s when I first started to teach speed training, many coaches and parents did not believe that speed could be improved.  Most people thought that you were either born with speed or not.   Research and the evolution of performance training completely changed this paradigm.  We now know that speed can absolutely be improved.  When looking into the science of speed training, one must ask, how do you actually improve an athlete’s running speed? 

Athletic speed comes down to a few basic principles.  First, an athlete’s sprinting speed is based on stride length and stride frequency.  This theory follows the notion that if you increase your stride length and increase your stride frequency, (number of strides an athlete performs per second) you will increase your overall sprinting speed.  This explains a basic understanding of speed but how do you increase stride length and stride frequency?    These questions can get more complex but it is my goal to keep it simple, so you can have a true understanding of how to increase speed.

First, we have to define stride length.  There are two ways to measure stride length.  The first and most common way is to measure the distance of one foot when it makes contact with ground, to the other foot when it makes subsequent contact to the ground.  This is referred to as “actual” stride length.  The challenge with this type of measurement is this process can cause an athlete to reach out too far and over-stride.  When an athlete over-strides, they reach out past their hips (center of mass) with each subsequent stride.  This over-striding causes an initial breaking force with each stride and limits speed.  The more accurate way to measure stride length is to think about how far the center of mass of the body is displaced forward on each stride, not where the feet hit the ground.  This is known as “effective” stride length.  A powerful stride should catapult the body’s center of mass, forward.  The feet should land under the hips on each stride, not out in front of them.      

One of most important aspects of improving “effective” stride length is improving relative body strength, better known as mass specific force.   Mass Specific Force is the amount of force an athlete can generate into the ground in relation to their own body weight.  The greater and faster the force generated into the ground, the more powerful and greater “effective” stride length will become.  This concept is achieved through strengthening the muscles throughout the lower body and core.  Proper warm-up, muscle conditioning and strengthening, as well as learning the right technique are all prerequisites on how to improve the ability to apply mass specific force more quickly and powerfully into the ground.

One of the most basic laws of physics to remember here is Newton’s third lawn… for every action there is an equal and opposite reaction.  Think of a young martial artist who first learns how to kick and punch.  When a young child starts out as a White Belt, they cannot generate enough force to break a board with a kick or punch.  What happens after a few months of training is they get a little stronger and improve technique, which enables them to break a board with a kick or punch. How did they do this?  They generated a greater amount of force in a shorter period of time.

Sprinting speed follows these same principles.  It is all about generating a quick force in a short period of time, just like breaking the board.   The difference with sprinting is that the force is transferred through the feet into the ground to propel the body forward. 
Once an athlete puts a quick force into the ground, they need to pick up their foot and get it ready for the next stride.  This is called “Leg Recovery.”   When sprinting, your feet are either on the ground applying force, or in the air preparing for the next stride. So we not only have to be efficient putting force into the ground, we have to be efficient in recovering our legs to prepare them for the next subsequent stride. 

I believe in the theory that if you become more efficient in the ability to recover your legs, you become more effective in putting a greater and faster force into the ground.  When you think about stride frequency when running at top speeds, you have to view each stride as a wind-up.  The more effective you can wind-up and cycle your legs, the greater and faster the force you can generate into the ground.   This cycling action becomes more proficient with practicing leg recovery technique drills.   

Let’s give you a simple equation to think about how to improve a 40 Yard dash time utilizing the theory explained above.  Let’s say the goal is to decrease the amount of time your feet stay on the ground by .005 seconds.  This is 5 milliseconds or 5 thousandths of a second.  Let’s also have a goal to decrease leg recovery time by the same amount.  This is the amount of time your feet are in the air preparing for the next stride. If you are able to do this on each stride, then the improvement would be .005 + .005 = .01 or 10 milliseconds.  This is where it gets interesting.  If you decrease each stride by .01, that means with the average athlete taking 20 strides in the 40 yard dash, you must multiply this improvement by 20.  So the improvement is .2 tenths of a second!  Two tenths of a second improvement in the 40 yards dash is a major accomplishment on any level, youth or professional. 

This is all very possibly if you understand what muscles you need to get stronger and how to apply that strength quickly, with the right technique.  So to summarize, Speed is about quick force production into the ground, that catapults the body forward with quick leg recovery, which sets up the next subsequent stride.   All these techniques are taught at the Parisi Speed School and with practice, any athlete can get faster.   

For more information about Bill Parisi and the Parisi Speed School, check out http://www.parisischool.com

(May 2016)