Running shoes explained: Parts, Specs and Features [+ best way to find yours]

You’ll often have running shoes explained to you by a running shoe salesperson, or from a running shoe retail website.

Unfortunately their job is to sell shoes so their “explanation” is often guided by marketing.

Having running shoes explained by a qualified professional is handy, but often it’ll only cover one aspect of the shoe due to time constraints.

So to get running shoes explained clearly, we got our running coach and Physiotherapist together to write a clear point-by-point explanation of each aspect of the shoe with their recommendations for each.

If you’re looking for Physio recommended shoes for specific issues, check out our Physio’s best shoe options for bad knees, calf pain and bunions.

Looking for the best WOMEN’S running shoes for wide feet, check out our post on cushioned, supportive, trail and racing shoes here.


Running shoes explained: Parts of a shoe

Upper

“Upper”, as the name suggests, is the upper part of the shoe that wraps around your foot.

It typically comes in a few forms:

  • Mesh design with integrated supportive straps
  • Mesh design with separate supportive straps
  • Woven material with localised support sections

Each of these materials are designed to hold the foot firmly against the base of the shoe, to avoid you sliding around.

If it’s too loose, you’ll slide around and likely get blisters, rolled ankles and no traction.

If it’s too tight across one part of the foot (usually the forefoot if the width is wrong), it’ll cause pressure areas and pain.

Although some of the original woven designs were a little loose after some wear, both coach and Physio are happy to recommend any of the types of uppers as long as they’re comfortable and fit “like a glove” straight out of the box.

Insole

This is the thin foam insert that goes in the shoe and under the foot – it’s removeable in most cases.

The insert is designed for showroom comfort and offers a tiny amount of extra cushioning when you’re running.

But it’s not to be mixed up with “orthotics” – purchased insoles that offer specialised support and/or cushioning.

By comparison, the insole that comes with the shoe is not supportive and only effective at providing a cushioned “feel” for a few weeks to few months worth of running.

If your shoes begin to feel a little “flat” after a few months and have lost their bounce, our coach recommends buying a pair of cushioning-only insoles (ie. no support) for around $30 to get it bouncing again.

Midsole

The midsole is the part of the shoe that does all the hard work, between the base of the foot and the grip on the bottom of the shoe.

It’s a cushioned and/or supportive material designed to absorb the impact and assist the foot in its journey from landing to take off.

It’s usually made of ethyl vinyl acetate (EVA), although you’ll also find it with gel, air and other materials in there.

This is what differentiates the feel of different shoes – the midsole comes in different density and thickness options.

It gives the shoe a feeling of bounce, softness, firmness, responsiveness, etc.

Our coach recommends finding your own way here – match the shoe to your personal preference for the feel you like when you’re running (some like to feel the ground, others like to feel cushioned/protected, etc).

Physio adds that it’s your preference for what feeling you like when you run, not how to feel in the showroom!

Don’t be fooled by the new shoe feeling – of course it’ll feel better that the old shoes you walked in with…

So when you get running shoes explained in the shop, ignore the comments of “they feel great, don’t they?”

Outsole

The outsole is a fancy name for the “grip” or tread of the shoe.

It’s made of a very durable industrial rubber material (usually PVC or polyurethane).

The outsole is designed to provide the right amount of traction on specific surfaces.

But be warned – getting the wrong type of outsole on the wrong surface can cause issues.

Our Physio comments that too much “stickiness” in the shoe and you’ll cause Achilles issues or tear a calf muscle.

Coach adds that while most runners are worried about slipping, it’s very rare and most tend to overcompensate with too much traction (Coach then went on about track spikes… we all smiled politely and kinda tuned out).


Running shoes explained: Basic specs

Heel to toe drop (aka. heel toe offset)

This very misunderstood spec is overemphasised when you get running shoes explained, and sometimes portrayed as changing the way you run.

It relates to the height difference between the rearfoot (heel) and forefoot of the shoe.

They are stated in millimetres and range from 0mm to 13mm for running shoes (side note: weight lifting shoes range from 16-25mm).

The drop/offset of a shoe relates to the angle of the foot when the shoe is flat on the ground – think of it as standing on flat ground or a little downhill nagle.

And much like standing on flat ground or downhill, it changes the loading on your ankle, calf and Achilles.

It doesn’t change the way that the foot hits the ground though – whether you’re a heel striker (which is more efficient and not more injury-prone) or a midfoot/forefoot striker, the only changes the tension on different structures.

Coach likes lower drop shoes (<6-8mm) for faster sessions and higher drops for easy and recovery sessions.

Our Physio agrees and notes that a variety of drops is quite healthy to share the load around.

While you might move to higher drop shoes to help recovery from a calf injury, remaining in higher drop shoes doesn’t protect you from future injury.

Side note: if you wanted to get the right shoes to help recover from a calf injury, or to alleviate calf pain, see our guide to selecting running shoes for calf pain here.

Stack height

This quirky little term refers to the overall height of the midsole + outsole under the heel.

Essentially it’s how high the shoe will raise you up from the ground.

It’s important because it relates to ground feel – whether you feel protected and cushioned or firm and responsive is directly correlated to the thickness of the material underfoot (along with density and a few other aspects).

Coach and Physio agree that it really comes down to personal preference of runner (protection and soft landing vs feeling impact and responsiveness).

Physio also notes that extra stack height isn’t necessarily protective of bone stress injuries!

As they found in research, more shoe cushioning makes the brain reduce the effort of biomechanical cushioning – basically your muscles won’t work as hard to soften the landing if the shoe can do it, but the overall result is the same impact forces on the bone.

Support level

Another very misunderstood aspect when you’re having running shoes explained by salespeople, this is the relative firmness of the midsole under the arch compared to the rest of the shoe.

It’s job is NOT to prevent pronation – you need that to move forwards!

It’s job is to guide the foot through it’s pronation movement, without allowing rapid or excessive movement.

This can be achieved through increasing the density of midsole material under the arch, although it’s worth noting that different brands position their support differently under the arch.

  • Brands like Brooks and Mizuno have support starting at the back of the rearfoot
  • Asics starts theirs from midway along the heel
  • Saucony and Adidas start theirs from just in front of the heel

There’s no right or wrong here – it needs to match the motion of your foot.

Physio comments that you can check for horizontal creases on your old shoes to show where you’re compressing the midsole and where you need the support to begin.

The Coach adds that’s it’s one of his biggest frustrations when athletes get the most supportive shoes due to salespeople or Physio advice, when it’s unnecessary and only restricts their natural movement.

Width

The “width” of a shoe relates to the width of forefoot section across the “ball of the foot”.

Some brands are known to be wider makes (eg. Brooks) and have more room, while some are generally quite narrow (there’s no “standard” sizing for shoes, for length or width).

Some models of shoes also come in narrow and/or wide fit options – you’ll see this written separately or after the size (eg. size 10 width 2E, or size 10 2E)

Shoe widths are consistent across male and female shoes, so a male standard D fit is the same as a female wide D fit in the same length of shoe (same length and EU size, not the same US or UK size).

The widths are:

  • 2A – narrow female
  • B – standard female, narrow male
  • D – wide female, standard male
  • 2E – extra wide female, wide male
  • 4E – extra wide male

Coach remarks that more width isn’t better – too much and you shift around in the shoe.

Our Physio adds that any orthotic support is useless if the shoe is too wide as you’ll slide off it like a sideways slippery dip (whatever that is…)

Volume

As a throwback to our high school days, the volume of the shoe is the overall space in the shoe.

Without being crude, it’s the difference between narrow dainty feet and fat chunky feet.

Brands are known for generally being high or low volume but there are variations within brands and between models.

If you get it wrong, it’s a giveaway when the shoelaces can’t bring the sides of the upper (where the lace eyelets are) closer enough together, or the two sides are touching.

Last

No, not the last item on the list, “last” refers to the shape of the shoe as viewed from underneath.

It’s one of the biggest considerations for buying shoes and one that’s rarely heard when you’re getting running shoes explained to you.

Running shoes are designed with straight lasts, universal lasts and curved lasts.

Straight last shoes look like you could draw a straight line down the middle and it’s evenly balanced on both sides.

Curved last shoes start straight through the heel and then bend away from the midline at the front of the shoe, bending towards the big toe.

Universal last shoes are halfway in between straight and curved.

Each brand has their typical last:

  • Straight last: Adidas, Saucony, Nike
  • Universal last: Asics, Mizuno
  • Curved last: Brooks, some New Balance

Coach comments that it’s why brand loyalty isn’t a bad idea. If you find a shoes that fits the shape of your foot, chances are that the brand will have other models that also suit your foot shape.

Weight

Simply the overall weight of the shoe.

But importantly, heavier shoes DO NOT require more muscle effort to run in.

This is because the additional work needed to move the shoe is offset by the reduced effort to stabilise the shoe on landing.

So shoe weight comes down to personal preference.

Physio states that some people compromise their preferred feel for a lighter shoe, believing they’ll run faster on race day.

That typically ends with unnecessary soreness and issues.

Coach adds that he’s a fan of lightweight shoes for races but they still need to be a match for your running and preferences.

For reference:

  • Lightweight shoes are usually under 8oz/240g
  • Heavier shoes are over 12oz/360g

Running shoes explained: Features

Woven upper

We mentioned this one at the start of the article.

It’s the material that the upper part of the shoe is made from and, while early generations of woven uppers had issues with becoming too loose over time, new versions are great for comfort and fit.

Dual density

This refers to the material used in the midsole.

The firmer density provides more resistance to compression under the arch of the foot.

It’s used to support (not prevent) pronation and reduce rapid or excessive movement of the foot.

It’s only effective if foot pronates far enough to reach the material, so the arch needs to almost flatten to get the support.

Medical grade orthotics are designed to bring the support to the foot and are more effective in injury management.

Guide rails

Brooks has moved away from dual density midsoles in 2021 and are now using “guide rails”.

Our Coach and Physio both get that look on their faces that suggests this one might be a marketing gem but not much more.

And that’s the big difference between having your running shoes explained by a coach/Physio/honest salesperson and a marketing-driven salesperson.

Guide rails don’t provide same level of support as dual density and most running shoe shops we spoke to are selling them as a step down from their stated level of support (so a moderate support shoe is being sold to offer minimal support).

Rocker shape

This refers to the shape of the base of the shoe, of the midsole and outsole combined.

It provides a rounded surface to aid in the smooth transition from heel to toe.

It’s seen in brands like Hoka, who pioneered the shape in running shoes, and it’s designed for efficiency for heel strikers.

Physio chimes in that heel striking is the best technique for long distance running for both efficiency and injury prevention, despite the bad press in the last decade or so.

And the rocker bottom shape isn’t just a marketing gimmick – it does what it says it does.

It’s also worth noting that the rocker shape reduces the impact of the heel-toe offset, so a 4mm drop would behave more like an 8mm drop.

Carbon plates

The biggest development of the last few years has been the addition of carbon plates to running shoes.

Who wouldn’t want to run a two hour marathon, right? (eye roll)

When it comes to running shoes explained, I reckon carbon plates takes up about 50% of any question time with runners.

Carbon plates are designed to provide maximal rebound from your impact force.

The concept is great, but there’s a few issues with its application.

From anyone who’s tried a pogo stick, the rebound forces are awesome but it takes a lot of muscle effort to brace for those forces.

That makes carbon plates good-ish for short races but terrible for regular training, mediocre runners or longer distances.

And although it’s been popularised by the media and elite runners, our Physio has seen plenty of running injuries that can primarily be attributed to carbon plated shoes.

Our Coach adds that if you’re trying to buy your way to performance, you’ve missed the point.

While carbon plates might get you a faster race time, so will honest training sessions and some strength work.

Rock plate

This is literally a thin plate contained within the midsole of the shoe to protect from rock impacts.

It’s found in some trail shoes from Salomon and similar brands for protection from painful rock impacts

It doesn’t affect the cushioning of the shoe but it does minimises ground feel slightly.

Overall it comes down to personal preference.

Outsole lugs

Lugs are the chunky rubber knobs or buttons on the outsole of the shoe for added grip on loose or difficult terrain.

Lugs for generally designed for grip on trails and different shape of lugs suits different surfaces.

Lugs vary from 3-6mm, from broad chunks to small bumps and from rounded to jagged.

Any lug-type grips are not suitable for road running – it shears off the lugs very quickly and makes your trail shoe into a gardening shoe.