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Are my feet getting bigger 1

By Steve Manning “The Footman” – intraining Podiatrist and Coach 

There is nothing worse than blisters causing you to pull out of a race. When your training, pacing and nutrition is all going well it can be ruined by a skin issue. Luckily, there are some easy ways to make sure that blisters do not undermine a great performance.


Blisters are formed when an external force causes stress between the outer layer of skin and the deeper layers. What starts as red inflamed skin can progress to a blister. At this point fluid forms between different layers of skin. The five outer layers of skin have no blood supply. If the blister forms in these layers it is a clear blister. If it is between these layers and the deeper dermis layer then you will get a blood blister.


There are two ways that blisters can form – a shearing force or a pressure force. A shearing blister causes friction and a build up of heat similar to a burn. They are formed by the foot moving inside the shoe. A pressure blister can be caused by a poor fit between your foot and the shoe or an orthotic. In this situation all of the force is localised to a single location.


Blisters can form anywhere there is excessive friction or pressure. Here are three common places for blistering.

Toes: Blisters usually occur on your toes when the shoe is:
– too short, hitting against the end of the shoe
– too shallow at the end of the shoe putting pressure on the toes
– too large and your toes try and grip the ground to hold the shoe on your foot
– the wrong shape for your foot.
Not enough space in the shoe can cause blisters between your toes as they rub against each other.
TIP: Try and match the shape of the end of your toes with the shape at the end of your shoes.

Arch: Blisters in the arch are more commonly formed by pressure rather than friction. The arches in some runners flatten more as they move from their foot flat on the ground to propulsion. If the arch in the shoe is too prominent for the foot then a blister will form usually at the front of the arch or the high point of the arch. Flat feet and flexible feet are more prone to these arch blisters.
TIP: An easy modification to your shoe can take the pressure off the arch. This is our most common footwear modification. Visit one of the intraining Running Injury Clinic podiatrists for help.

Heel: Heel blisters can occur if your shoe is poorly matched to the shape of the back of your heel. This can cause slipping of the heel or pressure on one part of your heel. If your shoe is too short then it can also increase the pressure on the back of your heel leading to a blister. Some runners have a lump on the back of their heel that is susceptible to blistering.
TIP: Tie your shoes and then stand up. See if you can stick a finger down around your heel. It should be a firm fit. You may be able to lace your shoes differently to reduce movement.


Blisters hurt initially because of the inflammation like a burn. After 24 hours the pain is mainly from the fluid pressure inside the blister. Draining the fluid at this stage will stop the blister hurting. You must be very careful with blood blisters that you do not let dirt get in the wound as it can cause a blood borne infection. As the skin drys it can go hard and cut into the deeper tissues.


My 4 top tips to prevent or treat blisters are:

Tip #1: Gradually increase your training
The best prevention for blisters is a gradual increase in training. When you first start back into running or even when you start using different shoes, your skin can be ‘soft’. With time, your feet will adapt and your skin becomes stronger.

Tip #2: File your callouses
Removing excess callous regularly will also reduce the risk of blisters as they often form between the callous and the deeper layers of skin. (shearing forces)

Tip #3: Check your shoe size and shape
Toe and arch blisters are regularly from the wrong shape, depth or size shoe. Allow space for the toes, and check that arch pressure.

Tip #4 Quality of your socks
Don’t underestimate the importance of the quality of your socks. Wicking fibres will not get abrasive and will maintain their shape and integrity. Anti-chafe wax’s and lotions are very effective for longer sessions and races.


Black toenails are blood blisters under your nail. They are often formed by pressure downwards on the end of the nail rather than just a short shoe. The result is a blister under the nail and the nail is then destined to fall off. You must be careful draining black toenails and it may be better to have it treated by a podiatrist if it covers more than half your nail. You should maintain short toe nails and cut them short a few days before any long race.

You don’t want blisters

Blisters can be small,  but mighty painful causing interruptions to your training or a limp in your important runs.   They usually can be an easy fix, but if you have tried everything to stop them, come see our intraining podiatry team. We know how to check if the way you run and your foot shape matches your shoes, and how to make the changes to stop blisters from happening. 

If you are having trouble with blisters, black toenails or calluses, book an appointment with our podiatry and team at intraining.  Call iHealth on 3870 2525.

Steve Manning 1

Steve Manning "The Footman"

Steve has been a running shoe aficionado for the last 4 decades and as the owner of intraining Running Centre has helped thousands of runners find the perfect shoe. He is a member of the Footman Biomechanics Group of the International Society of Biomechanics and a previous President of the Qld branch of Sports Medicine Australia. As a Podiatrist specialising in running sports injury prevention he utilises footwear prescription and modification to keep you running. Contact Steve at the intraining Running Centre, [email protected] for all your footwear questions.