Front and Backside Mechanics Front and Backside Mechanics refers to the position of the hip, knee, and ankle of the stance leg (front) and swing leg (back) during a sprint.

Ideally, after we take a step, our back leg, which is swinging forward should form a 90-degree angle. 1 The front leg on the other hand, which is driving backward, should be fully extending or straight at the ankle, knee, and hip. Simple enough.

Proper Front and Backside Mechanics

Easy and simple cues to teach this proper sprint pattern can be: “Drive the back knee up and push your front leg fully back and down into the ground. “ This specific technique will enable a maximal amount of force into the ground, which will maximize your stride length and distance between each step.

Also, you’ll notice that as one of these occurs, so will the other. For example, when the front leg fully extends, the back knee automatically lifts because there is an equal inverse relationship between the two anatomically. You can try this standing up. Lift one knee as high as you can with the knee and ankle on that same side at 90 degrees, and you will feel your balance foot drive into the ground and your glutes on that side light up.

Addressing Common Technical Concerns

Another question or issue that commonly arises is whether or not to focus on the swing leg or stance leg more when sprinting. Research has also shown that the function of the stance leg is far more important in creating more force and increasing speed versus the swing leg.

“Tests showed that the world’s fastest runner in the late 1990s reached a top speed of 11.1 meters per second, yet the amount of time he took to reposition his legs in the air was less than 3 hundredths of a second faster than sprinters who poked along at 6.2 meters per second, almost half the speed.” 2 3 However, in 2012, Morin identified that the swing does correlate with 100-meter performance.

The reason that the previous study failed to show the relationship is because it did not assess the acceleration phase and the entire race like this most recent one did, researchers said. In 1983, Mann also supported that the success of sprinting was due in large part to the relative activity levels of both the hip extending (backside) and hip flexing (frontside).

As far as technique is concerned, make sure the proper 90-degree angle of all joints of the swing leg is present to shorten the length of the leg, and make it easier to swing, which makes repositioning it back on the ground faster and everything else faster in the process.

Speed and technique of the swing leg are both vitally important. This technique also distributes the work more evenly across all hip flexors and muscle groups, reducing injury potential.

Dial In your Stride

You also want to make sure that you do not over-stride or under-stride, as this will cause impactful errors in frontside and backside mechanics. To prevent this, just make sure that the foot of the swing leg plants directly underneath the hip, so that you do not over-stride and excessively increase stride length and reduce stride rate.

Many hear “increase stride length” and they do this unnaturally. Just remember that your stride length should improve naturally as a by-product of the increased strength and power you build in the weight room. If your swing leg straightens at the knee too much, and you plant too far in front of your hip then you will over-stride, and a braking action will occur.

Stride Mechanics Ctd…

On the other hand, if your swing leg does not rotate forward enough, and you plant too far behind your hip, then you will under-stride and move slower.

To summarize, if your stride length is too long, you over-stride, and your stride rate and acceleration are slower. If the stride rate is too fast, you under-stride and your stride length and acceleration are reduced.

Your goal should always be to display the proper stride length at the fastest rate possible, without over- or under-striding to maximize your acceleration and speed output.

Scientific References:

#1-Hasegawa H, Yamauchi T, and Kraemer WJ. Journal of Strength and Conditioning Research 21: 888-893, 2007.

#2-Weyand PG, Sternlight DB, Bellizzi MJ, and Wright S. Journal of Applied Physiology 89:1991-1999, 2000.

#3-Ross, B. Underground Secrets to Faster Running. Bear Powered Running, 2005