Definition

Complete glycogen depletion during endurance exercise, causing sudden, catastrophic fatigue and the overwhelming desire to lie down anywhere. Cyclists' worst nightmare and the reason why energy gels exist.

Example Usage

I bonked hard at mile 18 because I forgot to fuel—ended up walking the last 5K.

Origin

Cycling terminology from the mid-20th century, possibly onomatopoeia for the sensation of hitting a wall.

Fun Fact

Bonking occurs when liver and muscle glycogen stores are depleted, forcing the body to rely solely on fat oxidation, which can't sustain high intensity.

Source: Endurance sports, particularly cycling terminology

Related Terms

Intermediate

deoxygenated

The process of removing oxygen from blood or water, basically turning your red stuff blue (or making your aquarium a fish graveyard). In fitness contexts, it's what happens to your blood after your muscles greedily steal all the oxygen during that last brutal set. Think of it as oxygen's eviction notice from your bloodstream.

⚽ Sports / Fitness
Advanced

overreaching

A planned short-term increase in training load that temporarily decreases performance, followed by adaptation and improvement during recovery. It's intentionally digging yourself into a hole with the confidence you can climb back out stronger.

⚽ Sports / Fitness
Intermediate

pyramiding

A weight progression scheme where you either increase weight and decrease reps each set (ascending) or the reverse (descending). It's the mathematical approach to training that makes you feel smart until you're too exhausted to count.

⚽ Sports / Fitness
Advanced

cluster sets

A set structure with brief rest periods (10-30 seconds) between small rep clusters, allowing higher quality reps with heavier weights. The commercial break approach to strength training.

⚽ Sports / Fitness
Intermediate

loaded carries

Exercises involving walking while carrying heavy objects in various positions, the functional fitness equivalent of helping your friend move furniture but calling it training. Surprisingly effective for building strength and questioning your gym bag contents.

⚽ Sports / Fitness
Beginner

compound movement

An exercise that works multiple muscle groups and joints simultaneously, like squats or deadlifts. The efficient way to get strong, as opposed to doing 47 isolation exercises for your biceps.

⚽ Sports / Fitness

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