Trail Running

A Trail Runner's Dictionary

The world of trail running has its own language. This can be both helpful and confusing to newcomers, so we created a short guide to help you understand the lingo.


  • Lugs: The sole of a trail running shoe has a series of lugs. “Luggy” helps to describe how rugged the lugs are on the trail running shoe.
  • Drop: Drop refers to the height difference between the toe and heel. It’s also called the “offset,” “ramp,” or “heel-to-toe drop.”
  • EVA: EVA (ethylene-vinyl acetate) is a lightweight, soft foam commonly used in a shoe’s midsole.
  • TPU: Thermoplastic polyurethane—TPU is commonly used as a stiff insert in the midsole for added protection. TPU can also be adapted to create a long-lasting, responsive midsole foam.
  • Rock Plate: A highly durable piece of material that protects your foot from rocks.
  • GORE-TEX™: A brand-name waterproof, breathable membrane. Many brands have a proprietary version of this as well.
  • Gaiter: A gaiter is a snug-fitting piece of material that protects your ankles and feet from debris.
  • Pronation: When your weight falls to the inside of your foot.
  • Overpronation When an inward rotation of the knee causes the ankle and foot to roll excessively inward.
  • Supination: When the outward rotation of the knee causes the ankle and foot to roll excessively outward (also known as underpronation).
Trail Running Shoes

Trail Lengths and Logistics

  • Vert: The vertical elevation gained in the ascent of a trail.
  • Out-and-Back: A trail that is linear and ends at the same location where you started. Typically, an out-and-back trail will have a scenic view in the middle.
  • Loop: A trail that loops around in a circular-like manner, starting and stopping in the same place.
  • K: Shorthand for kilometer.
  • 5K: A 5K run is a 3.1-mile run, walk, or hike.
  • Marathon: A marathon is a 26.2-mile run, walk, or hike.
  • Ultra: An ultra describes a run, walk, or hike with mileage that’s above 26.2 miles.
  • FKT: Short for fastest known time.
  • DNF: Stands for “did not finish.”
  • Tempo Run: Also known as a threshold run. Tempo runs can be sustained or done in intervals. A tempo run should feel comfortably hard and be conducted at a pace that allows you to run for at least an hour. You want to go no higher than 85-90% of your maximum heart rate.
  • Fartlek Training: Fartlek is the Swedish term for “speed play.” Fartlek is typically unstructured and switches between hard, moderate, and very easy intervals.
Trail Running Shoes

Trail Markers and Conditions

  • Blaze: A mark that indicates the direction of the trail. It can be a pattern or a color. Be sure to follow the blaze that correlates with the trail you’re on.
  • Cairn: A mound of stones that may also indicate the direction of a trail.
  • Climb: To gain elevation—it often references a short, steep section of a trail.
  • Switchback: A bend in the trail that doubles back over the trail underneath it. A switchback makes otherwise-steep trails easier to run or power hike.
  • Scree: Very loose rocks that often span a field.
  • Rutted Out: A deep groove in a trail caused by erosion, wheels, or use.
  • Bushwack: To navigate a densely wooded grove or terrain.
Trail Running Shoes


  • Gut Rot: The sensation that occurs when something you’ve eaten hurts your stomach.
  • Bonking: To hit a wall—experience fatigue, exhaustion, or lack of energy. Typically an indicator that you need more fuel or water.
  • Gel or Chew: A gooey or gummy substance high in calories that boosts energy quickly.
  • Bar: A calorie-heavy fuel source.
  • GORP: An acronym for “good old raisins and peanuts” or “granola, oats, raisins, peanuts.” Otherwise known as trail mix.
Trail Running Shoes