Page 105 - Journal of Special Operations Medicine - Summer 2014

An Ongoing Series

Prevention of Foot Blisters

Joseph J. Knapik, ScD

ABSTRACT
Foot blisters are the most common medical problem slow down or totally stop a Soldier. Broken blisters are
faced by Soldiers during foot march operations and, if open wounds subject to infection in the field because of
untreated, they can lead to infection. Foot blisters are the difficulties keeping out dirt and debris. Foot blisters
caused by boots rubbing on the foot (frictional forces), can limit tactical mobility and consume mission time,
which separates skin layers and allows fluid to seep especially if a Soldier becomes a major medical problem.
in. Blisters can be prevented by wearing properly sized
boots, conditioning feet through regular road marching,
wearing socks that reduce reduce friction and moisture, Causes of Foot Blisters
and possibly applying antiperspirants to the feet. Friction causes foot blisters. Even if your boots fit well,
some parts of the boot will press harder against your
Keywords: blisters, injury prevention, foot blisters, road foot than other parts. These “pressure points” are where
marching, footwear, load carriage, socks, antipersprants friction occurs. As you walk, your foot will move very
slightly inside your boot, and this sliding causes shear-
ing forces at the pressure points (Figures 1 and 2). Your
skin can tolerate a lot of frictional shear force but, like
Introduction
any other material, the skin has its limits. If the shear
This is the first of what will be a regular column that forces are great enough and you take enough steps, the
will inform you of scientific findings and practical sug- repeated pressure and rubbing will cause mechanical fa-
gestions on how to prevent injuries. Your author served tigue and your skin layers will separate. When the skin
in the military for 24 years, first as an enlisted wheeled layers separate, body fluids enter the split and you have
vehicle mechanic, then as a medic, and finally as a Medi- a full-blown blister. If you continue to walk without
cal Service Corps officer working in medical research
and development. For 21 years after military retirement, Figure 1 Blister (left) and broken blister (right).
I worked in research and public health at the Army Re-
search Laboratory, Army Institute of Public Health, and
Army Research Institute of Environmental Medicine.
For 25 years, I was involved almost exclusively with
issues related to injury prevention. I hope to convert
much of what I and others have found into practical
advice that might be useful to Special Operators. If you
have suggestions for topics, please send those to me at
joseph.j.knapik.JSOMonline.org.

This first column discusses foot blisters, which is the
most common medical problem faced by Soldiers dur-
ing foot march operations. Blisters may seem like minor
annoyances and they often are, but painful blisters can

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