30 years riding, 15 years writing
Bonk has long been a colloquial term, slightly jocular in its connotation, meaning sexual intercourse, but has recently become more commonly used as a jargon term by endurance athletes, primarily cyclists and long-distance runners, to describe a condition when the athlete suddenly loses energy and fatigue sets in, usually caused when glycogen stores in the liver and muscles are depleted, resulting in a major performance drop.
MTB: distance 26.80 miles, average speed 12.7 mph.