Suppose I am on a soccer field running, and the field is composed of grass and soil. I also own a pair of shoes in the shape of feet, so when I am put them on, it's really just rubber protection.

I am wondering: What would offer better traction, so I slip less: rubber, or skin? What is the larger coefficient of friction between both? On dry soil, wet soil?

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    $\begingroup$ I think it would be hard to answer this from first principles, so you would have to do the experiment. Experience suggests that rubber soled shoes provide more grip than bare feet, though I have never attempted to measure the coefficient of friction. $\endgroup$ Commented Nov 30, 2013 at 9:01
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    $\begingroup$ I just looked at info online, skin beats rubber by about .20. $\endgroup$
    – Jossie
    Commented Nov 30, 2013 at 19:59
  • $\begingroup$ @Jossie That's what I would have suspected, although I also suspect that it is true only on certain, dry surfaces. $\endgroup$ Commented Dec 23, 2016 at 6:21

2 Answers 2


The coefficient of friction of skin would depend on the moisture level, I think. For instance, if my fingers are dry, they slide easily across across each other. If they are moistened, they stick more to each other.


The coefficient of friction for rubber varies spending on what rubber (it's combination) you are referring to and is it static or sliding friction. It can be as high as 1.16 (coefficient of static friction) for rubber in combination with itself while it can be as low as 0.25 (coefficient of sliding friction) for rubber mixed with Wet Asphalt.

As far as Human skin is concerned it is again subjective to conditions for instance the location of the skin and whether it is wet or dry. The average coefficient of friction is 0.46 +/- 0.15 and the palm of the hand has the highest coefficient of friction 0.62 +/- 0.22 when tested with 5 materials namely aluminium, nylon, silicone, cotton sock, and Pelite.


  1. https://www.engineeringtoolbox.com/friction-coefficients-d_778.html
  2. https://www.ncbi.nlm.nih.gov/pubmed/10493141

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