Finding your perfect running shoes is different from choosing regular shoes. One big difference is the fit. Among other reasons, fit is an important factor when choosing shoes for running long distances, such as running a marathon. Here is a guide for how are ideal and how to select shoes with the right fit for you.


When should you measure your feet?

Focus on the fit
- The best time to wear test running shoes is in the afternoon.

In general, the left foot and right foot have different lengths from heel to toe. Furthermore, the size of the foot changes depending on the time of day.

Fit is an important factor when choosing shoes for running long distances such as marathons. However, people tend to choose their shoe size based on how the shoes feel on the foot rather than the fit.

Your foot will change size throughout the run, especially if you are running long distances such as a Marathon. This is because of increased blood flow and swelling, amongst other causes. You should pick shoes that fit well, not just ones that feel good. Otherwise, your feet might hurt come race day.

That’s why you should focus on the fit of the shoe for your entire foot. Your feet can get bigger in the afternoon. So, if you can, measure your feet or try on shoes at that time.

We recommend that when you visit a store and bring shoes and socks that your currently wearing. Sharing with the staff how your shoes are fitting is right now will help you find the best shoes for you.

How should it fit at the toe?

Pick shoes that are 1 cm larger than your actual size.
- Use your insole to measure if your shoes are the optimal size

Everyone has a different idea of what is a good fit in the toe box of a running shoe. With some runners liking their shoes to feel like a sock, and others preferring a more generous fit.

We recommend your shoe should have some space at the toes to avoid excessive wear and injury on the run. You can check the length this by pressing your thumb on the toes when you wear the shoe. Your thumb should make a small dent. When testing, make sure your foot is fully at the back of the heel.

The best shoe size is your actual foot length plus about 1 cm. If the shoe is too tight for your foot, you can do two things. You can get a bigger shoe that is 0.5 cm longer. Or you can get a shoe that is 0.5 cm shorter but has more room for your foot.

You can check if your shoes fit well by following these steps:

  1. Take out the inner sole from each shoe.
  2. Place it on the floor and stand on it with your heel at the back.
  3. Check the space left at the front.
  4. The shoes are the right size if there is about one index finger’s width of space at the toes.


Note: The fit of a running shoe will change depending on the purpose of the shoe. For example, a racing shoe will have a tighter high performance fit. Whereas, an easy run or trail running shoe will have a more generous fit through the toe box. Each shoe differs so that it can perform on the run it was designed for.


How should it fit at the heel?

Check if you have no pain or looseness at the Achilles tendon
- Excluding the toe area, your foot and the shoe should ideally feel as one

Follow these steps to ensure a good fit at the heel of the shoe.

  1. Wear the shoes and tap your heel on the floor a few times. This will make the shoe hug your heel better.
  2. Then tie the shoelaces once your foot is sitting at the rear of the shoe.
  3. If you have no pain or looseness at the Achilles tendon that’s a sign of a good fit.


Your heel should fit snugly in the shoe. If it is loose, it will move around when you run. This will make your whole body wobble and put more strain on it.

Your shoe should hold your heel firmly when you run. Your foot should feel like it is part of the shoe, except for your toes. They should have some room.

If the fabric inside the heel of your shoes is torn, it means your feet are moving excessively inside them. This is a sign your shoes are too big. Either the shoes do not fit properly or the laces are too loose.

If your heel gets loose fast, you can try a different kind of running shoes such as booty-style. The booty-type shoes at Mizuno are the Neo Collection and they have a sock-like fit.

How to tighten your shoelaces

Tighten your laces with the same strength as you ‘shake hands’
Tip: Drip water on the knot of your laces if they easily become loose

The most important factor in tightening the laces of your running shoes is the strength with which you tighten them. It is best to tighten them with strength roughly equivalent to when you shake hands.

You should always tighten your laces the right amount. If they are too tight, they will squeeze your nerves and make your feet hurt. If they are too loose, your shoes will not fit well and your feet will slide around. This will also hurt your feet.

Try running with the laces tightened at various strengths to find the tightening strength that is just right for you.

If you find that your laces come undone too quickly, after tying the bow, try tying another knot. You can also try putting two to three drops of water on the knot. This will make it harder for the laces to come undone.

1. How to Choose the best running shoes? 2. How should they fit? 3. How to clean my running shoes? 4. When should I replace my running shoes?