Ask an Expert is a recurring feature on our blog where we turn to the experts to answer your questions about all things foot health and shoes. Have a question you’d like to ask our experts? Send us an email!

To help answer your questions, we reached out to John Gerick, a Certified Pedorthist with decades of experience under his belt and one of our in-house experts. For this edition of Ask an Expert, he walked us through your questions about shoe inserts, design and sizing. 

I have extremely flat feet. Which A-Wave insert do I need, the Flex, Firm or XFirm?

The short answer is that it depends.

But that's not a very satisfying answer, so let's dig in, shall we?

With over 100 muscles, tendons and ligaments, along with 28 bones and 30 joints, the foot is incredibly complex. And it's also dynamic -- all of these parts must work together to keep you upright and mobile.

And given the sheer number parts involved, it's natural that there is wide variety of foot sizes, widths and shapes. It also means there's no such thing as a perfect foot or ideal arch height and that a flat foot on its own is not a bad thing.

Moving on, let's talk about the A-Wave for a bit. The Flex, Firm and XFirm are all designed with same arch height and they all have the same 3D shape. The difference between them is in the materials used in the arch. The Flex has the softest material in the arch with the most amount of give. The XFirm, as the name implies, has the firmest material in the arch and it will have the most resistance and provide the most support. The Firm simply splits the difference between the two.

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Now, here's where we get to the "it depends" part of the answer, and what it depends on is what you're hoping to achieve with the A-Wave.

The first question we need to ask is: are you looking to use an A-Wave because your feet, heel, or arch hurts? Or are you looking to use an A-Wave for added comfort?

If you're looking to simply add a layer of comfort and cushioning to your shoes, then you may find that the Flex will suit you just fine. The Flex is made of a softer material in the arch, so you'll still have arch support, but more importantly, you'll have the comfort and cushioning you're looking for.

If you’re looking for pain relief in the feet, heel or arch, however, there are two schools of thought as to how to solve the problem. The first school of thought is that a firmer material in the arch, like what's found in the XFirm, would be ideal. The firmer material can help slow down overpronation of the foot, thus relieving pain. Put another way, the firmer material in the A-Wave props up the arch, which could be especially beneficial if your flat feet are the result of fallen arches.

The other school of thought is that using firmer materials under the arch, and thereby adding more resistance to the natural motion of the foot as you walk, may be uncomfortable. If your feet have always been flat – that's just how they're built – then using a firmer material in the arch to try to prop it up like you would a fallen arch would not be helpful. Given this, a softer material like what's found in the Flex may be the most beneficial.

Having said all that, if you aren't quite sure what you need, you may find the SelectFlex® Rx to be a good solution. The SelectFlex has the ability to be adjusted with a provided key, allowing you to dial in how much arch support it provides. It's like having all three A-Waves in one product, allowing you to experiment so you can have a truly customized level of support.

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What is the difference between walking shoes and running shoes?

First and foremost, we would always encourage you to buy the shoe that's most comfortable for you and fits the best. If that means you buy a running shoe that you'll only ever walk in, that's totally fine. Comfort and fit should be your highest priority.

But, you asked about the differences between the two, which is a very good question. So, let's take a look!

For Apex shoes, the main difference between walking shoes and running shoes is in the materials used in the upper. With running shoes, you’re more likely to see a lot of mesh being used, while with walking shoes, leather usually dominates. But there are some tradeoffs involved.

If you're doing a lot of running, it’s likely that your feet will be doing a lot of sweating and will need good ventilation. That’s why you’ll see a lot more mesh fabric being used instead of leather in our running shoes. The tradeoff with mesh is that in exchange for excellent ventilation, you’re giving up the rugged durability of leather. Mesh is still pretty durable stuff, but it isn’t as stout of a fabric as leather.

But if you're mostly walking, your feet won’t be doing nearly as much sweating, making ventilation less of a concern. This allows us to use leather all around in our walking shoes, exchanging ventilation for a more rugged material.

You can easily see the difference between walking and running shoes with the Boss Runner and Lace Walker, two shoes which look nearly identical except for the leather and mesh (and the colors, of course).

With that said, shoes that you run in – whether it's a traditional running shoe or it's a walking shoe you use for running – will always wear out quicker.


With each walking step you take, you exert between 1 and 1.5 times your body weight on the heel of the shoe when the heel contacts the ground. With running, that force may be 2.5 to 5 times your body weight, which wears out the sole quicker. Given the same number of miles, shoes that are used for running will wear out a lot quicker than shoes that are used for walking.

Whichever style of shoe you choose, you should always stop wearing them and replace them as soon as they start to wear out – after about a year or about 300-400 miles, whichever comes first.

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What does a men's wide size equate to in a women's size?

This is one of those questions where it’s just plain difficult to give you a straight answer. Without getting too technical, let's just say that there isn't really a direct correlation. We recommend measuring your feet or having someone else do it for you so you can be sure you're getting the right size.

Check Out Our Shoe Sizing Chart.

Depending on what kind of shoe you’re looking for, you can then take your measurements and plug them into the men’s or women’s shoe sizing chart above and find the right size.

Have questions you'd like answered? Send us an email!

The information presented in this article is not intended to prevent, diagnose or cure any disease. This content has been created for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health provider with any questions or concerns you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

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