Speed is:
Stride Length x Stride Frequency
In order to run faster, you must increase one or both parameters.
Stride Length
is a product of limb length, power output, and flexibility. Typically, the best means of increasing stride length is by producing more power. This happens by increasing strength, power, and core stability.
It may sound a little bit funny, but many athletes actually increase stride length when they work to prevent “over striding.” Over striding occurs when you reach in front of your center of gravity in an effort to increase your stride length. This is a common mistake by novice runners and can really hurt your ability run fast. Just simply changing some sprint technique in this example can make an immediate impact on your performance.
PUSH, PUSH, PUSH!!!
The human body is designed to be much more efficient at pushing its center of gravity than pulling it. The primary movers of our body are the quads, glutes, and calves. They all work very well at moving the body by pushing the center of gravity either up or forward. The hamstrings are not very useful in propelling the body. So, if you attempt to lengthen your stride by reaching out in front of your body while sprinting, you have to first use your hamstrings to pull your body over your foot, then use your primary movers to propel you forward. This pull, then push approach is much less efficient and more time consuming than allowing your foot to drop right under your center of gravity, and then focus on pushing the entire time. Such a technique can also lead to chronic hamstring injury.
Train for Power
Solid Foundation
Hip position is also instrumental in stride length. Many of us have very tight hip flexor muscles (the muscles on the front of your hip which lift your knee). The problem with tight hip flexors is that they have a tendency to rotate your hips into a position which research shows can shorten your stride length. You see this in a lot 
of athletes who bend forward at the waist when they run. This forward flexion has been shown to decrease stride length by 1 inch for every degree of tilt at the pelvis. From experience, we can tell you that a 4 degree tilt is not very much, but it can translate to 4 feet of difference during a 40 yard dash.
Back in the 1990’s, many people criticized Michael Johnson for his awkward, upright running style, until he re-wrote the record books. The truth is, Michael Johnson had something figured out that many others didn’t – by running in an upright position with his hips and pelvis in a neutral position, he can maximize his stride length, and consequently his speed. You can emulate his running style by stretching your hip flexors and staying tall while you run.
The Ultimate Flexibility Guide
Knee up, Heel up, Toe Up
Stride length is also affected by your ability to recover to the “triple flexed” start position during the running gait. This triple flexion occurs when you reach the “knee up, heel up, toe up” position during the running cycle. Getting to this position places the primary movers in a slightly stretched position which essentially stores energy in the muscle to be called upon by the nervous system. From here, your body is ready to apply maximum force into the ground when your foot comes in contact with it.
Training your body to get into the triple flexed position is best done through running drills, such as the A march, A skip, High Knee run, and leg cycles. Repetition in these drills will help with any hip mobility issues that you may have and teaches the neuromuscular system to get your legs where you need them quickly and efficiently.
Understand the software of your body
Quality vs. Quantity
Recovery is King
Stride Frequency is improved by moving your legs through the leg cycle faster than it is used to doing. This is usually done by trying to get your legs move through the flight phase of the running cycle more quickly. The flight portion of the running cycle is defined as when your foot is in the air.
Teaching your legs to recover through flight faster is done by strengthening the hip flexor and core muscles and training the nervous system to work very quickly and efficiently. This can be done with plyometrics and jumping exercises, or with overspeed training. We recommend high speed treadmill training for attaining an overspeed effect, but it can also be done with cords, harnesses, pulleys, or by running downhill. Whatever method you choose is up to you, but the key is focusing on performing short, quick exercises which encourage the nervous system to work more quickly.
EXSpeed™…The Ultimate Tool for Speed Training
Other Factors
There are also a lot of other factors which affect your ability to run fast. Many are surprised to find out that your upper body and arms have almost as much to do with running fast as your legs do. Your legs can only move as fast and arms do. So, if you have slow arms or poor range of motion at your shoulders, it will affect your ability to run fast.
Your arms should move from the shoulder, not the elbow. In fact, your elbows should remain locked at 90 degrees with your hands relaxed while sprinting. Focus on pushing your elbow back as far as you can while running. It is very rare to see an athlete push their elbows too far back, but it is very common to see athletes raising their hands too high in the front. Your hands should never go above your chin level. Nor should they ever cross over the middle of your body. Stretching your upper body and taking time to work on upper body mechanics while running are the keys to improving this area of running.
Relax and Enjoy the Speed
Other areas which play factors while running are your head and neck. If you ever watch Olympic level sprinters, you will notice that even while running very fast, their face and neck are extremely relaxed, even to the point that their cheeks often look as though they are flapping in the wind. This is a concept called differential relaxation. Differential relaxation refers to an athlete’s ability to relax one part of their body (in this case their upper body), while working very hard and exerting extreme effort with another part of the body (the lower body here). Creating this separation can also be instrumental in sprinting.
