Running Sock Buyer's Guide

by David Spetnagel, Owner

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Well-fitting, well-constructed running socks are an essential tool in every runner's toolbox.  Since socks serve as the gasket between the foot and the shoe, faulty socks can make even an ideal shoe fit and ride poorly.  Our sock selection is better than its ever been.  When considering your next sock purchase, look for these features:

  • Synthetic or Merino Wool Fibers - When it comes to running socks, cotton is rotten.  Cotton fabric absorbs moisture (such as sweat) and gets rough and loses its shape when it does so.  Rough, distended fabric moving against wet skin is a recipe for serious blistering.  
    • In direct contrast to water-loving cotton, synthetic fabrics do not absorb water well.  (Imagine trying to dry off with a polyester bath towel rather than a cotton bath towel.)  When a runner sweats into a sock made of a synthetic fabric, the sweat is "wicked" or transported to the outside of the sock where it is, in turn, wicked to the outside of the running shoe's synthetic upper.  From there it can evaporate into the atmosphere.  Synthetic socks offer the highest likelihood that the foot will stay dry and the sock will maintain its shape and fit.  Synthetic fibers are superior in durability to natural fibers, as well. 
    •  Wool socks are always superior to cotton spcks - and in cold weather their thermal properties often make them superior to synthetic socks, as well.  Wool socks quickly and efficiently absorb sweat and precipitation, leaving a thin layer of insulating air between the foot and sock.  And as wool absorbs moisture - even from the air - a resulting chemical reaction actually generates heat!  In addition to being quite warm, wool socks are naturally odor-resistant.  Runners should stick to Merino wool socks, since Merino wool is smoother against the foot than other wools, and keep in mind that wool socks can lose their shape and gain weight as they become saturated, so synthetics are still superior for river runs.
  • Higher Thread Count - Just as fancy bed sheets boast about their high thread counts, so do technical socks.  Denser threads create a smoother fabric that reduces blister risk.  More threads create a more durable and cushioned sock, as well.  Look for socks with tighter and/or thicker weaves under the heel and the ball of the foot.  Thinner and/or less dense fabric on the top of the foot is fine; it enhances breathability.

Great fabric is only the start, however.  Check the following fit characteristics before buying:
  • Seamless Design - Seams cause unnecessary pressure on the foot, thus leading to hot spots or blisters.  The best running socks have no seams or carefully trimmed seams that go completely unnoticed by the feet.  Before trying on a sock, carefully examine the sock's interior seams after turning it inside out.  Pay particular attention to the entire width of the toe seam.


  • Deep Heel Pocket - Good running socks are sewn with a deep heel pocket that fully cradles the heel.  When the sock is on the foot, the heel seams should clearly indicate that the heel sits in the center of the heel pocket.  A good heel fit will keep the sock from sliding underfoot and "riding down" the heel, both of which introduce a blister risk.  When taken off the foot, the sock's heel should hold its "rounded" shape.


For those interested in getting an advanced degree in "sockology," two more characteristics should be considered:
  • Thickness - Shoes will fit better when the volume of the foot/sock combination hits in the middle of the bell curve; neither too low or too high.  Runners with average-volume/width feet are best served by average-thickness socks; high-volume/width feet do best with thin socks; low-volume/width feet benefit from thick socks.
  • Height - Protecting the foot from the "collar" of the shoe is an important sock role.  "Low" socks that stay hidden within the shoe and don't cover the round ankle bones or much of the Achilles tendon are usually fine for short runs, but not for long runs when the extra strides and sweat increase the blister risk.  Half marathoners and marathoners should have some ankle-covering socks in their toolbox.  Similarly, trail runners will do well with a higher sock that will assist in keeping trail debris from entering both the sock and the shoe.  Higher socks are great for cold-weather running, as well, adding some oft-needed protection between the top of the shoe and the bottom of your tights or pants.

After finding the perfect synthetic sock, it's important to properly take care of them.  Always turn them inside out before washing.  For synthetic socks, use a detergent such as WIN that is optimized to clean synthetic fabrics.  Wool socks can be washed with either that same "athletic gear-specific" detergent or a standard detergent.
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Along with wife, Debby, David Spetnagel opened Fleet Feet Sports in St. Louis in April 1993 after previously working as an aerospace engineer for NASA and McDonnell Douglas. David has since served as Senior Writer at Running Times Magazine, President of the St. Louis Track Club and of the St. Charles Runners Club, Executive Committee member of USA Track & Field's Ozark Association, and track and cross country coach at both the high school and collegiate levels.  Fleet Feet St. Louis has grown to include five stores and both training and race productions divisions.  A runner since 7th grade, David takes greatest pride in the streak of 1000 straight days of running at least 5K (3.1M) he completed in 2015.

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