Here is the classic, 44 year old, paper on the load-deformation characteristics of the plantar fascia for those podiatrists (and especially those podiatric surgeons) that believe that the plantar fascia can not be stretched (Wright DG, Rennels DC: A study of the elastic properties of plantar fascia. JBJS, 46 (A):482-492, 1964).
Kevin, can you please clarify the practical & clinical application of this paper ? The authors seem to conclude the stretching is really quite minimal and only occurs after quite a significant application of load i.e. 200lb ?
Good question.
The calculated change in length of the fascia was about 4% which in adult male foot would be approximately 6 mm of elongation of the central component of the plantar aponeurosis at 200 lbs of tensile loading force.
I would expect even greater elongation at the thinner, more distal sections of the plantar fascia.
Clinically, this means that the plantar fascia is elastic, spring-like in nature, elongates under load then shortens with decreased tensile loading forces.
It also means the midtarsal joint does not "lock" and is spring-like in nature, and that the plantar fascia is a tensile load-bearing structure that significantly contributes to multiple functions of the foot, that I have mentioned before multiple times on Podiatry Arena.
It also means that you cannot expect to cut the plantar fascia without causing a change in the mechanics of the foot.
Here are my 10 functions of the plantar fascia again:
I consider this paper
- The Biomechanicat Relationship Between The Tendoachilles, Plantar Fascia and Metatarsophalangeal Joint Dorsiflexion Angle
Robert E. Cartson*", M.D., Lamar L. Fleming, M.D.* and William C, Hutton, D,Sc.*
Atlanta, GA - Foot & Ankle
Int 21 1 2000
- to be very relevant to the clinical situation.
Using a cadaveric foot and ankle - In this experiment they pre loaded the Ach tendon and then dorsiflexed the hallux to predetermined angles and measured the change in length of the Plantar fascia.
The table below illustrates the relative strain of the plantar fascia.