Blister prevention for Runners
Blister prevention for Runners
By Steve Manning – Podiatrist BPod (Hons), Level 3 Coach
– 6 Common blisters, causes, treatment and prevention
Blistering and black toenails are the bane of runners. It is pretty disappointing when a blister rather than inadequate training or poor tactics leads to a sub-par performance.
There are different causes of blisters. Once a blister appears you need to identify the type of blister and the variables that led to it. The location of the blister is the key to treatment and prevention.
I have listed 6 common blisters below with a description of how they occur, treatment and prevention.
1. Blister between toes
Blisters between the toes are caused by friction as the toes rub together. This fiction will increase if your shoe toebox is too pointy or your toes are overlapping. Toe socks like Injinji are one of the best ways of reducing this risk as the friction is shifted to between the two layers of socks. Matching the shape of your foot with the shape of your shoe is also important.
2. Blister on the end of toes
Shoes that are too short or too long may both increase the risk of blistering the ends of your toes. Direct pressure from pushing on the end of the shoe is the most common cause of end of toe blistering. This can be fixed by making sure there is enough room for your toes at the end of the shoe. If your little toes are longer than your big toe then that will increase the risk of getting shoes too short. Shoes that are too long or wide can make you try and grip the shoe with your toes clawing the ends into the insole. Your foot may also slide down into the end of the shoe. Proper shoe fitting is the solution to prevent toe blisters.
3. Blister under toenails
Subungual Haematoma or Black Toenails are simply a blood blister under the nail. Once the blister has formed the toenail is no longer attached to the nail bed and will eventually fall off. Black toenails hurt when there is still fluid in the blister. After 24 hours they are safe to drain and then should no longer hurt. Do not drain them before this time as you may have a direct line to your blood and have a risk of septicaemia if they get dirt in them. They are generally caused by shallow shoe toe boxes but can also be from shoes that are too short. The best prevention is to cut your toenails as short as possible a few days before a long run or race.
4. Blister on the side of big toe or 1st Mpj
This blister usually forms under a thick callus that has formed. While poor biomechanics led to the callus, the blister happens when the hard callus moves independent from the deeper tissue. Keeping the callus thin with regular treatment reduces the risk but you may have to address the biomechanics that led to it. This is usually from rolling off the inside of your foot in propulsion. This will happen if you are toeing out but most commonly is due to a block in your big toe joint flexion. When it can no longer flex then you twist during propulsion to roll off the side of your foot. This needs to be addressed by a modification of your shoes insole or by orthotics.
5. Blister in the arch
Arch blisters may be caused by direct excess pressure or from a shearing force. The arch in modern shoes is built into the midsole rather than the insole. If the arch in the shoe does not match your foot then force will be focused on one spot leading to a blister. This can happen also with orthotics that have too high an arch especially if you have a rigid flat foot that can not conform to the arch. The blister may be at the high point of the arch but is most often at the front of the arch. Treatment is usually a modification of the shoe midsole where I remove a small wedge in the lip of the midsole at the arch. This is the most common footwear modification I do and has a very high success rate. In some cases poor foot biomechanics will need to be addressed with orthotics.
6. Blister in the heel
Blister in the heel can occur around the base of the heel or at the back of the heel. Blistering around the base is from a poor fit in the width of the heel counter in comparison to your heel. This can be a heel counter that is too wide or too narrow. Shoes with the wrong amount of stability will also contribute to this problem. Blistering at the back of the heel is mainly from your heel slipping in the shoe. Unfortunately modern shoes with a stiffer forefoot increase the chance of this happening. The shape of the heel counter may not match the shape of your heel. This can lead to damage on the inside of the heel counter which then traumatises the skin on the back of your heel. The right shoe fit makes a big difference in reducing these blisters but often the risk can be reduced by changing the lacing of your shoe. In some cases the addition of a cavity inside the heel counter that is covered with a smooth material is required.
General blister prevention:
1. Fitted footwear. Poor shoe fit is the main cause of blistering. The type and location of your blisters can direct us to choose the best model of footwear to purchase. I see patients on Thursdays nights at Indooroopilly Athletes foot.
2. Anti-friction creams. Bodyglide and Premax are two effective methods of reducing the risk of blistering. They create a film between your foot and external pressure or friction. The stress then occurs within the film rather than in your skin. They are highly effective for many blisters but may lose their effectiveness during longer races.
3. Wicking fibre socks. While the fit of the shoe is critical to pressure spots causing blistering the internal environment is also important. Socks are a more significant factor than shoes in keeping your feet dry and cool. Cotton socks are very absorbent but bunch up and get abrasive when wet. Socks with a high amount of elastic will maintain their shape reducing the chance of skin trauma.
4. Address Pathomechanics. Some blisters are formed because the foot is not working properly. A block in foot function leads to extra movement that may cause blisters. Orthotics in some cases are needed to address these problems when shoes, creams and socks are inadequate.
Steve Manning Podiatrist BPod (Hons), Level 3 Coach
I have patients who come to see me before major races to make sure their feet are in the best shape possible to reduce the risk of blistering and black toe nails. If you suffer from frequent blisters you should not accept it as an unavoidable part of running - Book in to see me at intraining Clinic.
Steve Manning works from the iHealth Centre Indooroopilly as a Podiatrist specialising in running injuries of the lower limb. He is also available for footwear consultations on Thursday evenings at Athlete’s Foot Indooroopilly. Steve is the Coaching Director for the intraining Running and Triathlon Club. If you're looking for tips and advice on super shoes, injury or an individualised running program, Steve can help with that too!