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bibliography * The PainScience Bibliography contains plain language summaries of thousands of scientific papers and others sources, like a specialized blog. This page is about a single scientific paper in the bibliography, Ahn 2011.

Short heels and big calves

Ahn AN, Kang JK, Quitt MA, Davidson BC, Nguyen CT. Variability of neural activation during walking in humans: short heels and big calves. Biol Lett. 2011 Feb. PubMed #21288939.
Tags: biology, barefoot, anatomy, biomechanics, running, foot, leg, limbs, pain problems, exercise, self-treatment, treatment, etiology, pro

PainSci summary of Ahn 2011?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. ★★★☆☆?3-star ratings are for typical studies with no more (or less) than the usual common problems. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.

Why does calf muscle size in humans vary so much? (It really does.) The bulkiness of the calf is an amplified sign of what kind of heel bone you have.

Specifically, Ahn et al. showed that calf size is probably driven by how far the heel bone projects backwards. They studied ten people of similar overall height and weight, lower limb length, and foot length and found that they were divided evenly: half were short-heeled with big-calves, and half had longer calcaneuses and more slender calves. They also looked at the neurology of the muscle recruitment. Folks with short heels and big calves were also using their medial gastrocnemius more than the lateral. So not only were their calves big, but they were pulling harder with the inside half of their gastrocs. By contrast, long-heeled humans appear to have more evenly distributed calf contractions.

~ Paul Ingraham

original abstract

People come in different shapes and sizes. In particular, calf muscle size in humans varies considerably. One possible cause for the different shapes of calf muscles is the inherent difference in neural signals sent to these muscles during walking. In sedentary adults, the variability in neural control of the calf muscles was examined with muscle size, walking kinematics and limb morphometrics. Half the subjects walked while activating their medial gastrocnemius (MG) muscles more strongly than their lateral gastrocnemius (LG) muscles during most walking speeds ('MG-biased'). The other subjects walked while activating their MG and LG muscles nearly equally ('unbiased'). Those who walked with an MG-biased recruitment pattern also had thicker MG muscles and shorter heel lengths, or MG muscle moment arms, than unbiased walkers, but were similar in height, weight, lower limb length, foot length, and exhibited similar walking kinematics. The relatively less plastic skeletal system may drive calf muscle size and motor recruitment patterns of walking in humans.

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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.