Running into Trouble: Lower Leg Injuries


                     by Joseph H. Fillmore, M.D.

Practically any part of the body can run into trouble for a runner.
Even hands and arms can get injured from a fall. A headache can take
on new meaning if you try to run in spite of it. Knees and feet may
get more attention in the domain of sports injury, but your lower
legs are right in there taking a beating every time you head out.
Injuries to the lower legs account for many running injuries and
they can stop you in your tracks.

                     How You're Built-Anatomy 101

The calf muscles are composed of the outer gastrocnemius and inner
soleus muscles (these are the large calf muscles at the back of your
leg), which the Achilles tendon connects to the foot. This
muscle-tendon complex allows for foot plantarflexion (the ability
to push the ankle down in order to stand on your toes or step on
the gas pedal). Beneath these muscles are the posterior tibialis and
flexor hallucis longus. The posterior tibialis enables the foot to
turn inward at the ankle and the flexor hallucis longus controls
flexion or downward motion of the big toe. The soleus, posterior
tibialis and flexor hallucis longus have direct attachments to the
major bone of the lower leg, the tibia (this is your shinbone).
These and the other muscles of the lower leg are divided into
groups or compartments surrounded by layers of fibrous tissue called
fascia. Irritation and injury to any of these structures, including
the nerves to the lower leg and blood vessels can cause calf pain.

                    How You Move-Biomechanics

Common biomechanical factors leading to injury include both excessive
pronation and supination of the foot, both normal motions of the foot.
However, when either pronation or supination is extreme, it can place
stress on the lower leg muscles and tendons. Pronation is more common
among flat-footed runners. Excessive supination is seen more often in
people with highly arched feet.
In order to determine if abnormal biomechanical factors are contributing
to lower leg pain, a thorough running analysis is needed. A sports
medicine expert, trained in biomechanics can make observations during
treadmill running.



                   Seven Ounces of Prevention

Although the running shoe industry may seem like a macho version of
the fashion industry with "hot" styles dominating the market (and
changing all the time), a serious runner can thank running shoe
technology for solutions to and prevention of many common running
problems. By choosing the right shoe for your foot and training style,
you are way ahead of the game. For example, a straight shoe may be
better if you tend to pronate too much. A curved last can be better
for the supinator. If you've had problems, consult a sports medicine
professional or a podiatrist for shoe selection advice.

Running shoes should be replaced at least every six months or earlier
if you cover more than about 20 miles a week. You should examine your
shoes regularly for wear and tear. Economy doesn't pay when running in
shoes that are breaking down. Check the outersole and the midsole
(pull out the innersole and inspect underneath). Place both shoes on
a countertop and check to see if either shoe tilts as viewed from
behind. This indicates excessive wear (or if new, faulty construction).
Using a shoe with a worn midsole can cause injuries due to decreased
shock absorption.

Visual inspection of the sole of the shoe can be like consulting a
palm reader to tell your future, only with a lot less guesswork.
Wear-patterns can identify abnormal biomechanical factors and predict
injury. For example, excessive wear at the ball of the foot on the
inside can indicate over-pronation. Inside the shoe can reveal some
secrets too. Wear under the first two toes can be a sign of
over-pronation.

                   Training Errors-Poor Judgement Hurts

Persistent high intensity training without low-intensity (easy days) is
one of the most common training errors. Runners can fall into the trap
of feeling as if more is always better and that taking it easy results
in losses that shouldn't be tolerated. Overly intense training without
allowance for recovery is one of the worst mistakes a runner can make
and it will almost always catch up with you one way or another.

Sudden increases in training load can also spell trouble. A general rule
of thumb is to keep increases of both mileage and intensity within 10%
and never increase both at the same time. Sometimes inexperienced runners
can push too fast during a race and wind up injured. The addition of new
(to you) training techniques like hills, plyometrics, or sprints should be
introduced carefully and gradually.


                   The Long and Winding Road-Terrain

Running on certain terrain may cause leg injuries. Persistent training on
asphalt or concrete can lead to increased mechanical stress causing
overload injuries of the joints, muscles, and tendons. Excessively soft
surfaces may cause hypermobility of the joints, tendons, and muscles
leading to overuse injuries. Running on uneven, rocky trails or slippery
roads can set the stage for ankle-twisting sprains. Canted surfaces (like
banked roads) can create problems if you always run on the same side.
Having one leg on the high side of the road can cause a functional leg
length discrepancy and result in injury.

                          The Injuries

Shin splints are actually stress injuries to the lower leg and are often
found in the inner and back part of the tibia. Professionals sometimes
call this medial tibia stress syndrome which includes tendinitis,
periostitis (inflammation at the site of attachment of muscle and tendon
on the bone) and stress fractures. Runners with this problem complain of
pain over the lower one-third of the tibia on the inner side. Sometimes
caused by over-pronation, there may be an enlargement of the tibial cortex
(outer part of the tibial bone) or tendinitis. Attachments of the soleus,
posterior tibialis, and the flexor digitorum longus muscle are located in
the posterior side of the tibia. These are all subject to stress injuries.
Treatment includes correction of any biomechanical errors, choosing the
right shoe, correcting training errors, and stretching and strengthening.

Achilles tendinitis is very common among runners. Increasing hill running
can help to cause this problem. Some runners even experience Achilles
tendinitis on both legs simultaneously. Pain is often noticeable when
getting up in the morning and with stair climbing. In contrast, large
tears of this tendon are characterized by an acute onset of localized,
severe pain, superficial tenderness and swelling. There are several
approaches to the treatment of Achilles tendinitis. Often heel lifts are
used to take the stress off the tendon.

Compartment syndrome refers to a condition in which muscle pressure
increases within the confines of the leg fascia and compromises blood flow
and function. Patients with chronic compartment syndrome complain of
fullness in the lower leg and a painful pressure that occurs at a specific
moment in training and may persist for hours after exercise. This pain
tends to increase with increasing activity. In certain cases, numbness,
tingling, burning or weakness can occur due to nerve impingement. At an
extreme, muscle cell death can occur with permanent damage. Treatment of
compartment syndrome is surgical release of the fascia. Conservative
management is generally unsuccessful.

Compartment syndrome in the posterior leg has been associated with
repetitive dorsiflexion and plantarflexion of the foot in runners. It may
be caused by a repetitive type trauma to the musculature causing a build
up of fluid and pressure in the compartment. This syndrome is suspected
when pain is localized in a particular muscle compartment and can be
bilateral in many cases. Diagnosis of compartment syndrome is made by a
medical procedure that measures the pressure within the compartment at
rest and during exercise to determine whether they are abnormally high,
particularly with exertion.

                       Do-It-Yourselfers Not Wanted

Chronic injuries, recurrent injuries, and serious injuries all deserve
professional attention. Determining the cause of an injury is often
difficult, and without knowing what circumstances created an injury a
runner is doomed to re-injury and rest cycles. Find a sports medicine
physician to work with you to uncover the cause of your pain. A
biomechanical assessment of your running style to determine abnormalities,
review shoe wear patterns and training history can be your insurance
against re-injury.

Treatment for biomechanical problems includes stretching tight lower leg
muscles, strengthening the weak ones, finding the right running shoes, and
using orthotics for motion control. Sometimes an over-the-counter shoe
insert is all that's needed to stabilize the foot. In other cases a custom
made semi-rigid orthotic is needed. Physical therapy is often recommended.

One of the best things a runner can do is to develop an understanding of
the importance of recovery in your training. The majority of injuries
could be avoided by incorporating rest into your schedule as a training
tool. Consider taking a week off in every six and alternate high intensity
days with low intensity days. Avoiding injury and overtraining guarantees
that your training will continue to progress. Becoming stale or worse
enduring full-blown overtraining syndrome or injury is like a boat with
torn sails-you're not going to get where you want to go.

(American Running Clinic Advisor, Joseph H. Fillmore, M.D., is a physical
      medicine and rehabilitation doctor from Denver.)

     Volume 19, Number 8, Running & FitNews
     Copyright, The American Running Association.