A common blister location
One of the most common areas for blisters is under the ball of the foot. You can get them:
Under the big toe knuckle (these ones)
Under the little toe knuckle or right in the middle
Less commonly right across the whole ball of the foot!
Anatomically, this is where the metatarsal heads are. These are weightbearing bones - so the skin is subjected to really high pressures. And as part of normal function, the metatarsal heads move back and forth under the skin, creating a lot of skin shear (the cause of blisters).
What happens under the foot?
The metatarsal heads move back and forth a lot with every running stride (it's normal):
during propulsion (push-off)
when changing direction
on uphill and downhill terrain
Let me explain: When the foot plants, the metatarsal heads skid forward over the skin, and then backwards during propulsion. Imagine what's happening to everything in between the skin (stationary) and bone (moving): it's being compressed and stretched. This is shear. Shear is normal, it happens with every step we take and our tissues are able to deal with a lot of it.
But you can imagine that as your activity increases in intensity and/or duration, shear may reach a point where it becomes excessive ... more than the skin can handle. At this point, damage occurs. And it occurs under the surface of the skin, a few layers deep. Blister researcher Stanley Comaish (1973) described this damage as epidermal fatigue because the connections that bind these skin layers tear under the shear load.
Why the ball of the foot is most susceptible to blisters
The metatarsal heads are subjected to really high weightbearing forces, unlike most other parts of the foot
The skin on the sole of the foot is thicker and less mobile than other parts of the foot and this is suited to blister formation
There are more sweat glands on the sole of the foot compared to other parts of the foot
The in-shoe microclimate plus the fabric composition of the sock and shoe provide a high friction environment by default
My best blister prevention advice for blisters under the ball of the foot
You can use any combination of blister strategies outlined on this page to help stop blisters under the ball of your foot. Things like socks that use specific fibres to provide a moisture-wicking function, blister taping and lubricants. But the best five are:
1. Taping - Preventive taping is a good place to start. In the following video, I'll show you a few options, pitfalls to avoid and a few different techniques to try. And where to get the tape I use.
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Fixomull Stretch tape (by BSN Medical) is used as a preventive taping and to secure dressings and paddings, such as donut pads. Fixomull offers an extremely strong adhesion with a reduced risk of allergies. Similar tapes do not provide the same stretch or adhesion.
Easy application to curved areas (watch videos below for application techniques)
Permeable to air and water vapour
Can be cut easily to any size and shape
Each roll is 10 metres in length and 5cm wide
2. Cushioned insoles - Cushioning has a double blister prevention effect. Firstly, it reduces peak pressure a little and therefore reduces skin shear. And secondly, cushioning materials absorb shear via their shear modulus. That is, shear goes on within the material so less of it occurs within the skin. Research has shown some cushioning does this better than others (read about Spenco, Poron and silicone gel materials in Chapter 5). But blisters often still form in spite of cushioning. Interestingly, the top surface of cushioning materials is typically high friction! So if you're still getting blisters in spite of cushioned insoles, add the next strategy.
3. ENGO Blister Patches - This is the best way to minimise friction under the ball of the foot. These patches stick onto the insole of your shoe (or orthotic) and they stay there until they wear through 500kms later. They just make blister prevention easy. Pictured are the large ovals. If you need broader protection, you can use the larger rectangle patches.
John Vonhof, author of Fixing Your Feet likes them too "ENGO Blister Prevention Patches are great. I have promoted them for years. I tell runners to pin one on their bib number before a race in case a hotspot develops. They work great on the insole for ball of the feet pain."
These oval-shaped ENGO Patches provide versatility for any blister situation. The shape makes them easy to apply to any area of the shoe and the size provides perfect coverage for most blisters. Most commonly used for blisters under the ball of the foot, top of the toes and edge blisters.
4 x Large Oval Patches (4.4cm x 7cm) in each pack
When you need big blister protection, Rectangle Patches provided protection for big flat areas of your shoe eg: across the ball of the foot; under all toes; areas on the upper of high-top boots, skates and ski-boots. Just like all ENGO Patches, these can be cut to any size or shape.
2 x Rectangle patches (7cm x 9.5cm) in each pack
4. Biomechanical improvements - Blisters under the ball of the foot are often associated with structural and biomechanical issues. There is a lot that a podiatrist or sports medicine professional can do to alter your biomechanics to reduce the incidence of blisters under the metatarsal heads. This could involve insoles, orthotics, stretches (especially calf stretches), joint mobilisations and modifications in your gait or running style.
5. Donut pads - I like these for treatment rather than prevention. If you have a blister, you'll need to take the pressure off it. The thicker the material (I use 5mm or 7mm orthopedic felt) the better the pressure relief - but the more room they take up in your shoe. If you get prevention right, you won't need these.
Use 5mm semi-compressed orthopedic felt to make donut pads, toe-props and wedges. Felt can be cut to any size and shape and lasts longer than standard foams and paddings.
22cm (width) x 45cm (length) per sheet
Single sheet of Hapla mixture wool felt
Medical grade adhesive, hypoallergenic
Can be cut to any size or shape
Self-adhesive, but be sure to cover dressings and paddings such as donut pads with Fixomull Stretch tape to secure long-term
Take home messages
The ball of the foot is inherently susceptible to blister development due to its important biomechanical functions in gait.
Good cushioned insoles or orthotic covers are a good start (something like Spenco)
Minimise friction best with an ENGO Patch
Consult a biomechanical expert for relevant advice and treatment
Written by Rebecca Rushton
Rebecca is an Australian podiatrist with over 20 years experience. She has spent a lifetime dealing with her own blister prone feet in her sporting and everyday life. Rebecca specialises in helping athletes and sports medicine professionals figure out how to manage foot blisters with ease. And for kicks, she enjoys providing blister care at multiday ultramarathon events.
Rebecca is the founder of Blister Prevention and author of "The Blister Prone Athlete's Guide To Preventing Foot Blisters".