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W. Ben Kibler, MD
Cindy Goldberg, PT, ATC
T. Jeff Chandler, EdD ABSTRACT Plantar fasciitis is an overload
condition that accounts for up to 10% of all running related injuries.
The pain is usually knife like at the insertion site of the plantar
fascia into the calcaneus, and is usually worse after periods of
immobility, such as in the morning and after a rest period.
In the early phases, the pain may resolve with activity, but
eventually may progress to causing pain during more daily activities.
Treatment usually consists of rest, injection, therapy, orthotic
intervention, and NSAID’s. Various biomechanical, anatomical,
and environmental factors can come into play with the development of the
condition. Anatomical
factors such as a navicular drop of more than 1.5 cm can lead to excessive
pronation, and is in fact the definition of a pronated foot.
Training errors, high arches, and leg length discrepancies are all
also factors. However, many
persons suffer form these conditions and do not develop plantar fasciitis.
This study wanted to find if there are more predictive factors that
could be used to identify those who may develop the problem. Three groups were created for this
study. One group actually
consisted of the symptomatic foot in athletes with a high degree of
running in their training. The
group consisted of 43 persons, mean age 31, with definitive diagnosis of
plantar fasciitis. The second
group consisted of the opposite limb in these individuals, which was not
symptomatic. The third group was a control group made up of 45 age and sex
matched athletes who participated in sports that did not require the
extensive running seen in the first group.
Testing included measurements for
ROM, isokinetic strength testing of the ankle plantar flexors and
dorsiflexors, first ray evaluation, Brody navicular drop test, and general
manual muscle testing. The
isokinetic speeds used were 60 and 180 deg/sec.
It was assumed, as previous studies have indicated, that the peak
torque at 60 deg/sec should approximate one half of the body weight, with
the dorsiflexors, invertors, and everters being approximately one fourth
of the body weight. Peak
torque values at 180 deg/sec should not drop off by more than one half
their low velocity values. Values
were considered abnormal if they were greater than 15% weaker than the
opposite limb, or out of the norm values. Results indicate that plantar
flexor weakness and lack of dorsiflexion motion were the two factors that
seem to have occurred significantly in cases of plantar fasciitis.
The authors were not sure if this was a cause or an effect, but
noted that in the persons with fasciitis in one foot, the opposite side
also showed lack of DF, just not as much as the involved side.
This may indicate that the weakness is the more dominant of the
two, and the one more responsible for the development of fasciitis.
The authors conclude that lack of DF ROM results in increased
pronation during the gait cycle, and the weakness causes adaptation due to
the inability to propel, as one should.
Also, the weakness may play a role in decreasing the shock
absorption capabilities of the foot. COMMENTS An old article I just dug out while
cleaning out some folders. I
would say that most, but not all, understand that lack of dorsiflexion ROM
can lead to excessive and delayed pronation, and thus undue stress on the
plantar fascia. The authors
did not address conditions of equinus, or bony lack of DF, in this patient
population. The plantar
flexion weakness is one that many therapists probably either ignore or do
not address. The typical MMT
for the plantarflexors is having the patient perform 10 calf raises.
Sure enough, most people can do this, unless in severe pain.
However, this test is not going to pick up a 15% deficit in
strength that an isokinetic test can pick up.
Therefore, I have always incorporated calf raises into the program
for these patients. While
this study did not find any deficits in DF, IN, EV strength, I have seen
it clinically. Often patients
with plantar fasciitis come along slow, and then progress rapidly once the
ankle strengthening is initiated.
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