One article on PainSci cites Cheung 2006: Complete Guide to Plantar Fasciitis
PainSci commentary on Cheung 2006: ?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided wherever possible.
This is a tricky thing to measure directly, so this was a modelling study, a “thought experiment” extrapolating from biomechanical properties of the leg, ankle, and foot. The methodology does cast some doubt on the reliability of the results, but it’s certainly a lot better than an educated guess. Specifically, they modelled the response of plantar fascia tightness to Achilles tendon tension. The authors reported that “increasing tension on the Achilles tendon is coupled with an increasing strain on the plantar fascia.”
~ Paul Ingraham
original abstract †Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.
BACKGROUND: The plantar fascia, which is one of the major arch-supporting structures of the human foot, sustains high tensions during weight-bearing. A positive correlation between Achilles tendon loading and plantar fascia tension has been reported. Excessive stretching and tightness of the Achilles tendon are thought to be the risk factors of plantar fasciitis but their biomechanical effects on the plantar fascia have not been fully addressed.
METHODS: A three-dimensional finite element model of the human foot and ankle, incorporating geometrical and material nonlinearity, was employed to investigate the loading response of the plantar fascia in the standing foot with different magnitudes of Achilles tendon loading.
FINDINGS: With the total ground reaction forces of one foot maintained at 350 N to represent half body weight, an increase in Achilles tendon load from (0-700 N) resulted in a general increase in total force and peak plantar pressure at the forefoot of up to about 250%. There was a lateral and anterior shift of the centre of pressure and a reduction in the arch height with an increasing Achilles tendon load as a result of the plantar flexion moment on the calcaneus. From the finite element predictions of simulated balanced standing, Achilles tendon forces of 75% of the total weight on the foot (350 N) were found to provide the closest match of the measured centre of pressure of the subject during balanced standing. Both the weight on the foot and Achilles tendon loading resulted in an increase in tension of the plantar fascia with the latter showing a two-times larger straining effect.
INTERPRETATION: Increasing tension on the Achilles tendon is coupled with an increasing strain on the plantar fascia. Overstretching of the Achilles tendon resulting from intense muscle contraction and passive stretching of tight Achilles tendon are plausible mechanical factors for overstraining of the plantar fascia.
- “Association Between Plantar Fasciitis and Isolated Gastrocnemius Tightness,” Ngenomeulu T Nakale, Andrew Strydom, Nick P Saragas, and Paulo N F Ferrao, Foot & Ankle International, 2018.
- “Validation of a New Device for Measuring Isolated Gastrocnemius Contracture and Evaluation of the Reliability of the Silfverskiöld Test,” Marius Molund, Elisabeth Ellingsen Husebye, Fredrik Nilsen, Jan Hellesnes, Gøran Berdal, and Kjetil Harald Hvaal, Foot & Ankle International, 2018.
- “Clinical Implications of a One-hand Versus Two-hand Technique in the Silfverskiöld Test for Gastrocnemius Equinus,” Jr Goss, Joseph Long, Adam Carr, Kyle Rockwell, Nicholas A Cheney, and Sr Law, Cureus, 2020.
- “Modulation in the elastic properties of gastrocnemius muscle heads in individuals with plantar fasciitis and its relationship with pain,” Ji-Ping Zhou, Jia-Feng Yu, Ya-Nan Feng, Chun-Long Liu, Pan Su, Su-Hong Shen, and Zhi-Jie Zhang, Sci Rep, 2020.
This page is part of the PainScience BIBLIOGRAPHY, which contains plain language summaries of thousands of scientific papers & others sources. It’s like a highly specialized blog. A few highlights:
- Is Neck Posture Subgroup in Late Adolescence a Risk Factor for Persistent Neck Pain in Young Adults? A Prospective Study. Richards 2021 Phys Ther.
- Photobiomodulation therapy is not better than placebo in patients with chronic nonspecific low back pain: a randomised placebo-controlled trial. Guimarães 2021 Pain.
- No effect of creatine monohydrate supplementation on inflammatory and cartilage degradation biomarkers in individuals with knee osteoarthritis. Cornish 2018 Nutr Res.
- The CANBACK trial: a randomised, controlled clinical trial of oral cannabidiol for people presenting to the emergency department with acute low back pain. Bebee 2021 Med J Aust.
- Relationships Between Sleep Quality and Pain-Related Factors for People with Chronic Low Back Pain: Tests of Reciprocal and Time of Day Effects. Gerhart 2017 Ann Behav Med.