Nowadays people throw out HUGE amounts of money for running shoes, spikes and many other types of shoes, and they all have unique purposes for whatever it is you are doing! I decided to take a look at a number of shoes in a series of blog posts and examine just how these sports companies use physics to make their shoes the best technical shoes in the market!
In this blog we will examine just the generic running shoe and what must be considered in making it. Any sort of running shoe you have to expect will be going through miles and miles wear and tear as the shoe wearer goes down roads, trails, treadmills and much much more. The biggest thing the shoe designers are thinking about is actually the impulse (PHYSICS TERM) that the shoe goes through when it strikes the ground each stride. So lets examine this more closely.
Impulse by definition is the change in momentum of an object such as the impulse delivered by a bat to a baseball. The impulse delivered in each stride is very great for a shoe because every time a shoe strikes the ground it becomes motionless for a very small amount of time meaning the entire body wearing the shoes also does. Therefore when designing the shoes engineers have to create a shoe that will absorb this massive impulse over and over again. The padding that is added into the shoe provides just this so that not only the shoe survives constant use but also the foot that is wearing the shoe.
Another thing to consider though with such a shoe is the weight. If you add too much padding then you risk creating a heavy shoe that might feel like landing on a pillow but also feels like lifting an anchor off the ground. This relates to the Newton's simple second law which says net force equals mass times acceleration, meaning a larger mass implies a larger required net force. Of course a larger net force makes for a slower runner which presents the problem to designers of padding versus weight.
Hope you enjoyed this post next up spikes, speedy footwear or pointy sneaker of death?!