Screen Shot 2014-08-15 at 11.21.05 AMNearly 20 million people completed a running race in the year 2013—that’s more people than populate Belgium, Chile or Switzerland! Considering runners could band together to occupy an entire country, it is no surprise we’ve developed our own language of jargon and lingo only a fellow runner would understand.

Below we’ve selected and defined some of the most puzzling running terms. So whether you’re new to the running scene, a non-runner trying to make sense of your significant other’s running rambling or simply need a refresher, keep on reading for a crash course in running lingo, jargon and abbreviations.

  • Bonk: a sudden drain in energy and feeling of intense fatigue during a race or hard run. Scientifically, bonking is caused by a depletion of glycogen in the muscles and liver. Mentally, it feels like you got hit by a bus.
  • C25K: Stands for ‘Couch to 5K’ a common training plan for new runners looking to complete their first 5K race.
  • DNS / DNF: Abbreviation for when a runner Did Not Start’ or ‘Did Not Finish’ a planned race.
  • DOMS: ‘Delayed Onset Muscle Soreness’ is muscle soreness that plagues a runner 12 – 48 hours after a race or particularly hard workout. Quick tip—avoid stairs during this period!
  • Dreadmill: The dreaded treadmill. Get it?
  • Fartlek: A Swedish term for ‘speed play,’ this is an unstructured speed workout. During the workout a runner can choose random distances or time periods to increase the pace—think of it as an interval workout gone rogue.
  • Hardware: A race medal! Often worn all day after a race and then proudly hung in one’s home.
  • Hitting The Wall: (see bonk)
  • Intervals: A structured speed workout often run on a track. A runner alternates high intensity running with periods of recovery running. Yasso 800s are a popular and simple interval workout.
  • Junk Miles: Easy or recovery miles. Don’t be deceived though, despite the negative-sounding term, ‘junk miles’ are an essential part of training.
  • LSD: No, no that’s not the elusive runner’s high everyone talks about! An abbreviation for ‘long slow distance’ this is a run that focuses on getting in high mileage rather than worrying about pace.
  • Naked Run: To run without technology—gasp! Once in a while ditch the GPS watch and heart-rate monitor, but please, keep your clothes on.
  • Negative Splits: To run faster the second half of a race or workout.
  • Runner’s High: A moment of complete and utter bliss during a run.
  • RunRocker: People who believe in the power of music to inspire, motivate and drive. People who know right song at the right time can help them run faster, longer and stronger because of how the music affects them.
  • Streaker: A person who, for an extended period of time, runs every single day. Once again, please keep your clothes on!
  • Taper: A period of days or weeks before a race in which a runner begins to significantly dial down the mileage, in order to be physically rested and fresh for race day. Be careful, tapering runners are prone to mood-swings, anxiety and intense hunger.

There you have it, the most perplexing running terms defined. Got all that? Have any other terms you’d like defined? Let us know in the comments!