But first, Newton's 3rd law
When your foot makes ground contact, the ground pushes back with the same force in the opposite direction (blue arrow below). This is Newton's 3rd Law in action.
foot ground reaction forces newtons 3rd law
The body is good at absorbing vertical forces (purple arrow) but struggles with horizontal forces (orange arrow). The horizontal force at ground contact is referred to as braking force. 
foot ground reaction forces newtons 3rd law horizontal and vertical
8x the injury rate

Yes, 8x. Our body was not designed to take high braking forces.

Runners with a peak braking force over .27 their body weight are 8 times more likely to be injured running.

What does this have to do with overstriding?

Overstriding is when your foot lands in front of your knee. Basically, you are overreaching with each step. 
overstriding gif pareto pr1 insole overreaching
In the above video, the runner's foot is traveling forward at ground contact with the entire mass of the runner behind it. The ground is pushing back with an equal and opposite force.

To make matters worse, when overstriding the knee is not in a position to properly absorb the forward momentum at ground contact. Think about jumping off a curb and not being able to bend your knees at impact. 
overstriding gif pareto pr1 insole overreaching
The runner's entire mass has to pivot over the knee. This transmits tremendous force up the leg.

How does the PR1 fix overstriding?

The PR1 helps you shorten your stride.

The PR1's sensor is positioned under the back of the heel so it can notify you when you're overstriding. The feedback helps you take shorter more controlled steps.
pareto pr1 correct foot strike foot knee hip
Here the runner is landing with their feet underneath their knee. The body no longer has to pivot over the knee, helping to maintain forward momentum. 

Visit our shop to get your pair of PR1s and start moving better. 

Charlie Bennett