Runners often ask why they experience difficulty when training in a new training shoe. Inevitably I see the same pattern repeated (i.e., running in only one pair of shoes until they are exhausted). Running shoes can be expensive so I understand the need to train in one pair of shoes from an economic perspective.
However, it is worth investing in multiple pairs of shoes from several standpoints. First and foremost, you are less likely to become injured when you rotate multiple pairs of running shoes. Your lower extremities won’t become accustomed to the range of motion of just one pair of shoes. You get far more mileage from your running shoes when you rotate multiple pairs because the midsoles are allowed to rest between runs. Most runners don’t realize running shoes require rest.
The majority of running shoes have midsoles comprised of EVA (ethylene vinyl acetate) or air blown rubber. EVA contains thousands of tiny air bubbles that act as shock absorbers. You are placing several times your body weight on your lower extremities with each footstrike. Multiply the number of miles run x 1000-1500 footstrikes per mile and you’re placing a ton (no pun intended) of force on your legs and feet. This compresses the tiny air bubbles in an EVA midsole and they require between 24-48 hours of rest to expand back to their full resiliency. If you only wear one pair of running shoes you’re likely to wear them out prematurely.
Most runners look at the outsole to determine whether their shoes need replacing but it’s actually the midsole that compresses and wears out first. If you listen closely to your body you will start feeling aches and pains when your midsoles have completely compressed and are no longer absorbing the shock.
The reason runners experience difficulty when going to a new shoe after training in just one pair is due to the completely compressed midsole and the excessive range of motion your experience going through your entire gait cycle. Running in a new pair of shoes is a shock to your system because you’ve gone to a completely different end of the spectrum.
Rotating multiple pairs of shoes will reduce injury and provide far more mileage from each pair. Running in multiple pairs of running shoes is initially expensive but ultimately far more economical because you enjoy more miles from each pair. I recommend staying within the same model or genre (i.e., stability, neutral or cushioned) of shoes, provided you’re happy with them, when choosing multiple shoes.
Develop a shoe strategy that works for you and your will significantly reduce the risk of injury and dramatically improve the quality of your runs!