hoof spreading

Question
hello sir, back tracing your previous answers on using aluminium or steel shoes in racing, this was your answer:
"HI ALUMINUM SHOES ARE USED FOR LIGHTNESS AND RACING AND STEEL SHOES ARE USED FOR HEAVY TRAINING AND KEEPING THE FOOT FROM SPREADING TOO MUCH.SOME TRAINERS WILL RACE THEIR HORSES IN STEEL RACING PLATES FOR A MORE RUGGED AND LONG LASTING RACING SHOE. SOME OTHER TRAINERS WILL ONLY RACE IN ALUMINUM SHOES. THANKS ED HESS"
sir, here what do you mean by "hoof spreading too much". does it literally mean, the horse hoof expands too much on touching the ground. so, to fix this problem, we use steel shoes. is it correct?? if i'm wrong, please correct me!!!

Answer
hi. steel racing plates will keep the foot from spreading too much in a race. as you know when the horses foot lands on the ground , it lands heel first, then on to the rest of the foot, ending with the toe, so all of your pressure is on the heel of the foot, so the steel plate will keep the foot from spreading out too much. aluminum is a softer metal , so therefore it will allow the horse foot to open and close more when hitting the ground. it is up to the trainer to decide what type of shoes to wear on what particular horse. if you use caster oil on a horses foot regularly, you will keep the foot in excellent shape for racing what ever shoes you decide to use.  hope this helps you. thanks ED HESS