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Study: Plantar fasciitis strongly linked to tight calf muscles


Tags: etiology, plantar fasciitis, biomechanics, pro, foot, leg, limbs, pain problems, overuse injury, injury, tendinosis

One article on PainSci cites Nakale 2018: Complete Guide to Plantar Fasciitis

PainSci summary of Nakale 2018: ?This page is one of thousands in the 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 at the bottom of the page, as often as possible.

As of 2018, a hypothetical link between plantar fasciitis and calf tightness remained poorly studied. This study sought to put the question to rest with the right design and enough patients. They measured gastrocnemius extensibility in three groups of people: 45 with plantar fasciitis, 117 with other foot and ankle problems, and 61 healthy people.

80% of the plantar fasciitis patients had calf tightness, compared to 45% of the people with other foot problems, and only 20% of the healthy people.

Calf tightness is obviously prevalent in the population. 20% of healthy calves is a lot of calves, and “almost half” of calves in people with miscellaneous foot problems other than plantar fasciitis is also a great many calves. But 80%? That’s even more!

The comparison of calf tightness in plantar fasciitis versus other kinds of foot trouble is important, because it clearly suggests that there’s something about plantar fasciitis in particular — not just any pain in the area — that involves calf tightness. Calf tightness may well be a cause and/or reaction to any kind of lower limb trouble, but it is linked quite a bit more strongly to plantar fasciitis specifically.

Note that the Silfverskiöld test may have poor reliability (Molund 2018, see Is Diagnosis for Pain Problems Reliable?), which would cast doubt on the results of this study. However, it’s likely that the inaccuracy of the test leans towards underestimating calf shortening (Goss 2020). Also, other more recent and objective data has backed these findings up (Zhou 2020).

~ 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: An association between plantar fasciitis and isolated gastrocnemius tightness has been postulated in the literature; however, there have been few studies to prove this relationship. This prospective cross-sectional cohort study was aimed at determining the association between plantar fasciitis and IGT.

METHODS: Three groups comprising 45 patients with plantar fasciitis (group 1), 117 patients with foot and ankle pathology other than plantar fasciitis (group 2), and 61 patients without foot and ankle pathology (group 3) were examined for the presence of isolated gastrocnemius tightness using the Silfverskiöld test. Statistical tests included chi-square test, Student t test, and analysis of variance.

RESULTS: Of the patients, 101 (45.3%) had isolated gastrocnemius tightness: 36 (80%) in group 1, 53 (45.3%) in group 2, and 12 (19.7%) in group 3. The difference in isolated gastrocnemius tightness prevalence between the groups was statistically significant at P < .001. The prevalence of isolated gastrocnemius tightness was similar between acute and chronic plantar fasciitis at 78.9% and 80.6%, respectively.

CONCLUSION: There was a very strong association between plantar fasciitis and isolated gastrocnemius tightness using group 3 as a reference. This study suggests that isolated gastrocnemius tightness should be actively sought out and managed in patients with plantar fasciitis.

LEVEL OF EVIDENCE: Level II, cross-sectional cohort prospective study.

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