In the clinic, I’m often asked about minimal running. Sometimes, patients are asking about barefoot running while others are talking about minimal shoes. I’m going to focus on minimal shoes. There are varied definitions associated with “minimal” shoes. There are different possibilities when combining the slope of the footbed (i.e. heel-to-toe drop) with the height of the footbed off the ground and so many other characteristics. So we are on the same page…minimal shoes have a very small or no heel-to-toe drop. A type of minimalist shoe that has approximately a four millimeters heel-to-toe drop is sometimes called a transitional shoe. A true minimal shoe has a drop of zero degrees or has a flat footbed.
Why Wear a Minimal Shoe?
Traditional shoes inhibit the natural function of the foot. The foot is a mobile and impressive structure. It is made up of 28 bones and four arches. It is meant to be adaptive. Putting a foot in a typical shoe is like tying your shoelaces while wearing thick gloves. With the limited ability to feel and the thickness of the gloves getting in the way, it is difficult to tie your shoes. Wearing a traditional running shoe is much the same. The nerves on the bottom of your feet need to be able to feel the ground, so they can react. This feeling provides input for your feet to become flexible at specific times to absorb your body weight and rigid to allow you to push off the ground when running. In addition, this input is necessary to coordinate the musculature of your feet to maximize the efficiency of movement. Most likely, you have been wearing a shoe with lots of cushion and a high heel-to-toe drop. It is going to take time and a system to adapt to a minimal shoe.
Running with more minimal shoes has also been related to reducing running impact. Running can produce 2.5 times your body weight in force. This force has been directly correlated with an injury in many studies. Some studies have found that a shoe with a higher heel-to-toe drop (greater than four millimeters) is related to increased force. When wearing a traditional shoe, the foot initially hits the ground in an excessively dorsiflexed position (i.e. toe up), putting the foot in a more rigid position, hence increasing the ground reaction force. This position is also related to overstriding. Overstriding is when the knee is very straight (i.e. less than 20 degrees) when the foot first contacts the ground. This overly straight position places more stress on the knee joint and creates more impact that is transferred up your body through a kinetic chain of energy.
You should consider a more minimal shoe to prevent inhibition of the natural function of the foot and increased force. This will help to reduce the chance of injury and maximize your efficiency.
So How Do I Transition?
The first step to determining whether you should try to wear minimal shoes is to ensure that your body is able to adapt to the change. Jay Dicharry, MPT and Mark Cucuzzella, MD made a great video that describes four tests that you should pass before considering wearing a more minimal shoe.
If you pass the following tests described in the video, then you can have more confidence in the transition process. If you didn’t pass, that doesn’t mean that there is no hope for you. It just means that your feet may have some structural, strength, or mobility issues. By practicing these tests, you may have success in the future or your feet may require more support. You can still have a minimal shoe with great support. Just make sure that the shoe has the following characteristics:
Comfort – The shoe must be comfortable on day one. It will most likely not break in. This is especially important at the front or toe box of the shoe. Your toes need room to spread to absorb impact. It is best to go shoe shopping at the end of the day after your foot has widened from the impact you placed on it throughout the day.
Firm Cushioning – It may sound nice to run in a soft and squishy shoe, but softer shoes act as a barrier to your feet. The nerve endings in your feet will not be able to feel and adapt to the ground as well.
Lightweight – This is more common sense. You are going to be running lots of miles. There is no use lugging around a heavy shoe.
Match the shoe with the terrain – If you love running and competing on the trails, then wear a trail shoe. The tread and design of the shoe should match how you train.
Toe box fit – When trying on the shoe, be sure that you have about a half inch from the end of your longest toe to the end of the shoe.
Toe box width – An easy way to figure out that the toe box or the front of the shoe is good for your foot is to pull out the manufacturer’s insole and put it on the floor. Step on the insole. Your entire foot should be contained on the surface. If not, then consider a shoe with a larger toe box. When you are running, your toes need to spread apart to provide you a good base of support.
Shoe shape – The shoe shape should be similar to your foot shape. Most shoes are semi-curved. This means that if I take a straight edge, such as the edge of the shoebox, place it on the bottom of the shoe and divide it in half, then the straight edge connects with the third and fourth toe area. Compare the shape of the shoe to your foot. They should be about the same. In some cases, you may find a shoe that is more curved than your foot or straighter than your foot. If the curve of the shoe doesn’t match the curve of your foot, then torsional stress could be placed on the sides of your foot creating discomfort and altered support.
Perpendicular heel counter – The heel of the shoe should be perpendicular to a flat surface. Be sure to check this out just in case there was a design or manufacture error.
Bend of the shoe – The shoe needs to bend with your toes. The goal of your shoe is to not hold your foot captive but to protect your foot and let it do its job.
A good rule of thumb for shoe shopping is to start with a shoe that has a heel-to-toe drop that is half of your current running shoe. If you have been running in a traditional shoe with a 12mm drop, then find a shoe with approximately a six mm drop. The math doesn’t have to be perfect but close.
Once you’ve found the shoe, take your time to incorporate it into your training. Start by regularly walking at least 30 minutes at a time in the new shoes for about one to two weeks. Then begin running in the new shoes. This should be a VERY gradual process. There are many ways to increase the volume. A simple way to add new shoes to your routine is to run only a small percentage of the time in the new shoes. Then wear your traditional shoes for the rest of the run. Gradually increase the running time in the new shoes.