Some of us will do anything to set a PR, others will do anything that is legal under "the rules", others yet will only do that which they deem ethical in their pursuit to run faster than they ever have. No matter which box you like to place yourself in, crossing your eyes will fit within your rules.
Not all athletes are affected by gravity equally. Of the many reasons for this, it appears alignment plays a pivotal role. Athletes that excel show similar physical characteristics that could classify them as being in tune, whether or not they are conscious of it, with the sacred geometry of the body/universe.
By crossing the eyes you can learn how to move your core in a straight line.
Stand in front of a mirror, preferably full length.
Cross the eyes ever so slightly. You should now have two seperate images of yourself. Place the image of yourself that is on the left next to the image of yourself on the right. When they appear to be next to each other, lock them in place so you can observe the subtle irregularities of your body that are slowing you down, such as that right shoulder that is lower and closer to the core than the left shoulder. Locking the images in place will likely be difficult for those interested enough to try. In time though, it begins to feel as if there are two seperate internal pathways running up your body and they seem to stop right at the eyes, by controlling these pathways you can eventually lock the images in place and become as symmetrical as you have time for.
Words have a way of trivializing anything that has not been experienced before, please keep this in mind.
By learning how to run with the eyes slightly crossed you can figure out how to run the tangents of a course truer as well. Those willing to work on this will find that when they run crossed the image on the left is not always horizontal to the image on the right, but may appear to be higher or lower, or even skewed somewhat.
When looking at a stationary object that aligns you with the next tangent that needs to be hit on the course you will know that you are running a true line towards it (as opposed to the slight wobbling/precession that occurs with nearly all humans)when you can cross the eyes, lock the dual images in place next to each other, and keep them aligned with each other in respect to the horizontal energy grid/gravity.
Maybe it will make more sense to some if they think of drawing a line that is on a piece of 8 1/2" x 11" paper and must be parrallel to the top and bottom of that paper. If we want to be sure of ourselves we would likely mark two spots on the paper, say 4 1/4" down from the top on the left and the same on the right, then we connect the dots. Now picture your whole life you have been doing your best, and possibly not even that, at trying to draw a straight line with only one of those points of reference. Make it easy on yourself already, cross your eyes and reveal the second point.