Ask the Doc...
By: Dr. Lou Pack
“My son wants to run faster. He has foot inserts, but they haven’t helped. Do you have any suggestions?”
There are many factors involved in creating speed, one of the most important components in any sport. Among these are genetic predisposition, conditioning, coaching and determination. So his inserts may not be a factor at all. That said, a really good set of custom foot inserts can make all the difference in the world, but they must be extremely precise and, unfortunately, most aren’t.
The normal foot (whether walking or running) hits the ground on the outside of the heel and then rolls inward (adapting to the surface). This motion is called "pronation," and a certain amount of it is necessary. The problem is that most people pronate or roll in excessively. This is not only wasted, time-consuming motion, but leads to all sorts of injuries.
The goal of a custom performance foot insert is to hold or stop the foot at its ideal position and not let it roll in any further. This allows the foot to be on the ground less time, which translates into faster speeds. The foot will also be a much more rigid, powerful lever, with quicker push off. That’s exactly why sprinters use a starting block; to have a more rigid lever to propel from. So an ideally corrected foot insert is like having a starting block in your shoe for every stride you take!
Studies have shown that if you can decrease the amount of time the foot is on the ground by only five one thousandths of a second (and remember that a blink is one, one thousandth of a second), you can decrease a 40-yard dash time from 4.8 to 4.6 seconds or less. That’s a significant amount for a competitive athlete, and a really good set of custom inserts can do that.
But saying you have an insert or foot orthotic is like saying you have a car; that could mean just about anything. To work effectively, the foot must be casted in its ideal position and not the position it usually functions in. That means sitting and not standing, when abnormalities are seen. If the foot mold is made while standing, then these abnormalities are captured and the devices cannot be made as accurately.
So if everything else is in place, the reason your son isn’t running faster is probably because his inserts aren’t optimally corrective. There’s a difference in buying a pair of corrective eye glasses at a drug store and having prescription lenses made after seeing a real authority.
A former Clinical Instructor of Medicine at Emory, Dr. Pack practices at MCG Medical Associates, at Reynolds Plantation. He works with patients who have arthritis and wish to decrease joint symptoms and remain active. He also treats athletes at all levels, including Olympic gold medalists, and helps the UGA Golf Team. For further information please see www.drloupack.com, drloupack.blogspot.com, or call (706) 454-0040.