If you were to observe the mechanics of running in slow motion, you would realise what a complex operation it is. There is the first point of contact between the heel and the ground, then the whole sole progressively makes contact as the heel takes off in the air and your toes give you the momentum to advance further. Some would say that it is poetry in motion, but we say there is a lot of mechanics and synchronisation of your muscles, ligaments and joints in performing a seemingly effortless and smooth move, when in fact it is so complex.
What Is Pronation?
Now that you have envisioned the entire sequence of a running step, let us understand when and where pronation occurs. Pronation is the inward rolling of your foot as it makes contact with the ground. It is a perfectly natural movement, and it helps you maintain balance and helps your lower leg absorb the shock of the contact of the sole with the ground.
What does it have to do with your running performance? Everything! Correct pronation helps you achieve and maintain a good running speed without over-exertion and without placing too much strain on your lower leg muscles. However, not every foot has the same type of pronation and specialists have identified three categories: neutral pronation, overpronation and underpronation.
Everyone, from doctors to physical therapists, refrains from using the term “normal” pronation, however this is the adequate type of pronation, ensuring adequate shock absorption. Neutral pronation occurs when your foot rolls 15% inwards as it makes contact with the ground.
If your foot has a neutral pronation, you will notice a S-shaped wear on the inner sole of your running shoes. This shows how the pressure is distributed across the length of your sole and it is a uniform distribution. In other words, the shock of hitting the ground is uniformly distributed along your foot with a good rate of shock absorption, allowing you to increase your running performance without straining your muscles or risking injuries.
Overpronation means that your foot rolls inwardly with more that 15% from the flat standing position. In this situation, your foot and ankle are not offering your body proper stability and your lower leg muscles have to absorb more shock than is healthy, especially in the long term. Also, at the end of the cycle of movement, the whole pressure is applied on the big toe and the one next to it, instead of being distributed evenly among all your toes.
If you are an overpronator, you will notice that the wear of your shoe is more accentuated on the inner part of the sole and under the ball of your foot, being more accentuated under the big toe.
Overpronation causes your legs to do more work to keep you stable on the running track. You will use up your energy inefficiently and may risk knee and hip muscle injuries in the long run.
Underpronators do not roll their foot inwardly, but outwardly. This type of running posture is also known as supination (you will need to learn these terms when you start looking for running shoes, as we will explain in the next paragraphs). One of the biggest problems caused by underpronation is the constant strain on the sole of your foot and your ankle muscles and ligaments, increasing your risk of ankle sprain, IT band syndrome, Achilles’ tendonitis and plantar fasciitis.
If your running gait is underpronated, your running shoes will tilt outwardly when you place them on a flat surface.
Correcting Inadequate Pronation
The simplest way of achieving a correct pronation and reaching your maximum performance in running is to buy running shoes which offer you optimal support for the whole foot. Depending on the type and degree of roll of your sole, you will be recommended a different shoe model that offers more support and a thicker foam layer exactly in the part where your foot is most likely to roll in variance to neutral pronation.
If running in adequate running shoes does not solve the problem, your physical therapist will recommend you perform special exercises to strengthen your foot muscles and correct your running gait.