Tuesday, January 9, 2007

The Need for Speed

I often joke that I only run when chased. In the past I ran a lot and fell out of love with it deciding it was time to see other exercises. At CrossFit I could ignore the fact that workouts had 400/800 meter runs in them knowing that if I lost a few seconds, I could make it up during the strength elements. But everyone in class is getting stronger and I haven't necessarily gotten any faster. It's time to correct that:

By: Mauro Di Pasquale
Three components affect your maximal speed: Stride Frequency, Stride Length, and Anaerobic Endurance. Here's a quick look at all three & how they work together.

Part One: How Speed Is Created
When watching a race you probably have noticed that each person looks like they run differently. These differences are biomechanical in nature.

Everyone can improve his or her basic speed. There are three factors (other than genetic) that determine how fast a person runs:
  • Stride Frequency - This is the number of strides a person takes in a set amount of time.
  • Stride Length - This is the measured distance of each stride taken.
  • Anaerobic Endurance - This is your body's ability to sustain maximum effort for an extended time frame.
All three of these factors are dependent on each other for the creation of speed. In other words, a person cannot become faster without improving all three components. For example, the number of strides a person takes in ten seconds will only make them faster if the length of each stride is greater than another's. This is exactly what I will address.

Conversely, if one person's stride length is the same as another's, they will not be faster unless the frequency of their strides is greater. Finally, we have anaerobic endurance. Without it, stride frequency and stride length are inconsequential because you are physiologically not able to run at maximal effort.

Part Two: Stride Frequency
Stride frequency is defined as the number of times a foot touches the ground in a given amount of time (usually seconds). This determining factor of maximal speed is the most difficult to change, and thus, has the smallest affect on speed production.

However, because the movement of the lower leg with each stride affects it, it is important. More specifically, where the foot touches down with relation to the rest of the body can affect stride length, which in turn, affects stride frequency.

Basically, if the foot touches down behind the body the stride has been shortened. A shortened stride causes a slightly greater frequency rate. Conversely, when the foot touches down in front of the body the stride has been lengthened. Stride lengthening slows the frequency rate of your stride. This is typically called over-striding in speed training. Over-striding is the most common mistake made by sprinters in relation to stride frequency.

When the foot strikes directly under the body and the lower leg is 90 degrees (or perpendicular to the ground), stride length is optimal. This allows the athlete to reach his or her optimal frequency, which allows the sprinter to maintain maximal speed.

Additionally, where the foot touches down with relation to the body, and how often it touches down, can be influenced by biomechanics, or movement of the hip, knee, and ankle joints.
There are a few specific sprint technique drills which can influence the movements of the hip knee and ankle joints which will help maximize the sprinters technique as it pertains to optimal stride frequency.

Nine Exercises For Sprinters! The basic idea of these exercises is simple. Explode off the ground, and then once your feet touch, explode again spending minimal amounts of time on the ground. [ Click here to learn more. ]

Part Three: Stride Length
Stride frequency is one of the max speed factors. This will explain the definition and practical influence of stride frequency and how it affects maximal speed. Stride length is defined as the distance between touchdown of the toe of one foot and the touchdown of the toe of the other foot. This factor varies greatly from sprinter to sprinter. Stride length can even change for an individual depending on whether he or she is racing at longer or shorter distances.
However, we're not going to get into all of that. Instead, we will focus on how, either by shortening or lengthening your stride, you can better obtain your maximal speed potential.
First of all, the length of each stride can vary due to several factors including but not limited to:

Leg length
Biomechanical technique.

It is relatively easy to determine a persons optimal stride length. All that you need to do is watch where the foot is with relation to the upper-body when it touches the ground.
Optimal position of touchdown should be somewhere between six and twelve inches in front of the sprinters center of gravity. Touchdown any closer to the body's center of gravity (or behind it) will cause a decrease in force applied to the ground.
The greater the force applied to the ground, the greater the speed.

Conversely, touchdown any farther away from the center of gravity and the foot will act like a brake. This over-lengthened stride decreases the amount of force applied to the ground. This, in turn, will slow the sprinters maximal speed.

So, generally speaking, in relation to the sprinters center of gravity, if the foot strike is behind the center, the stride is too short. If the foot strike is too far in front of the body's center, the stride is too long.

What this all means is that a greater stride length will help a person become faster, only if it does not slow stride frequency or decrease the amount of force applied to the ground.
As I mentioned earlier there are specific drills that can be practiced to help an athlete maximize his or her stride length, as well as, stride frequency. I will discuss these in the final installment of this series.

Part Four: Technique Drills
Of the three max speed factors, two of them, stride frequency and stride length, can be improved by executing a few simple drills while training. Here's a look at them.

Now that you understand that speed is a product of both genetic ability and biomechanics (or technical form), I will walk you through a few technique drills that will help you learn and develop proper running form.

There are two drills that can help anyone become faster, if practiced and perfected. They are the "A" and "B" drills. The "A" drill precedes the "B" drill, and both are to be learned in a progression from marching or walking, to skipping and finally running.

Sprint Technique Drill #1 - A's
This is a simple drill to help the sprinter achieve high knees and toes when the leg is up in front of the body during the sprinting motion.

Begin by simply walking forward slowly, while staying up on the ball of your foot. As your toes leave the ground to step forward, dorsi-flex the ankle or pull your toes upward toward the knee and hold them there. While holding your ankle in this position, flex the hamstring and pull your heel upward toward your buttocks.

Then, using hip flexion, pull your upper leg and knee forward and upward parallel to the ground. Note, at this position, your ankle should be underneath and slightly behind your knee with your toe still flexed upward. Then simply extend the hip and knee and put your foot back on the ground.

When you start doing this drill, begin by repeating the same leg for several repetitions before switching to the other leg. Once you become more comfortable with the motion, alternate in a normal walking gate, then speed up to a skip, and finally perform this drill at a slow running pace.

The "A" drill helps to improve both stride frequency and stride length. Flexing the tow upward and pulling the heel directly to the buttocks shortens the leg, thus allowing it to be pulled through the range of motion more quickly and will help to increase the speed or frequency of the stride. While holding the lower leg in this position and flexing the hip to raise the knee parallel to the ground helps to assure the stride length is optimal.

Sprint Technique Drill #2 - B's
"B" is simply a continuation of the "A" drill. To perform this drill, begin by doing the "A" drill, once your knee is parallel to the ground, flex the quadriceps muscles and swing the lower leg forward and upward. Similar to when you are kicking something. By doing this, you are simulating the leg swing that naturally occurs when running.

Remember, at this point, you are performing this drill at a walking pace. As you progress with more speed, the lower leg will extend on its own because of forward momentum.
When your knee is fully extended, use your hamstring to pull the entire leg backward and downward towards the ground. Think of this as a pawing action. Pulling the leg back with this movement causes the foot to touchdown nearly under the body's center of gravity, and allows the force of the next stride to be applied at the proper angle and direction so speed can either increase, or at a minimum, be maintained.

Start practicing this drill just as you would with the "A" drill. Begin by repeating the same leg for several repetitions before switching to the other leg. Once you become more comfortable with the motion, alternate in a normal walking gate, then speed up to a skip and finally perform this drill at a slow running pace.

There are other factors that play a part in the production of speed. However, stride frequency and length are the most crucial and most difficult to maximize. Practice these drills, perfect them, and apply them when you are sprinting at full speed. You will become faster!

This article was edited for space.