About the feets going numb. There's three points that you need to set just right in order to avoid this: one is obviously the length of the strap that you set with the hex bolt on the far end. But there are two other ones that I think most people may not know about. You have to set the angle just right on the other end where it is attached with the bolt and philips head screw. If it is in too sharp of an angle it can cause numbness and even be less efficient since there will be part of your shoes that don't even contact the straps. You have to set this just right, trail and error is key. The third point is something I've recently learned about, where you tighten the straps with the hex wrench: it helps if you fold the straps uneven. Don't fold it even steven because it will make the strap too rigid at the point that it folds. The fold that is closest to the hex bolt head should be a little less than the one furthest. After I did this, my feet were very happy yet I still can spin with a good amount of power. You just have to experiment. A lot of small variables.