OK, Here's a fun one; we did some beta testing with volunteers on the Runner's World forums and feedback was very positive: myStride plots the average force experienced each time your foot hits the ground. You can compare various ways of running, different footwear, and instantly see the results. Thinking of switching to barefoot running, or just want to smooth out your stride? Attach your phone to your leg, run for a minute or so, and look at the results. This app was inspired by the paper "Foot strike patterns and collision forces in habitually barefoot versus shod runners" (Nature, 2010) by Lieberman et al, in which the authors present evidence that barefoot runners naturally adopt a forefoot strike, which reduces impact transient forces. In their work, they used a steel force plate to measure force. If you're like us, you don't have one of those lying around. However, if you want to analyze your stride to reduce force, or just repeat the original experiments out of curiosity, myStride lets you do it. Try it out: run with shoes, then run barefoot. See what the graphs look like!