The term bonk for fatigue is presumably derived from the original meaning of hitting, and dates back at least half a century. His first citation in the oxford english dictionary is an article from 1952 published in the Daily Mail. People often associate the word bonk with hitting the wall during resistance events. For endurance athletes, it's a sudden and overwhelming feeling of running out of energy.
You were running or riding at what seemed like a manageable pace, and then, apparently, without warning, your legs turned to cement. With heavy legs, a feeling of fatigue all over the body, and sometimes dizziness, you are forced to stop. bonking occurs when muscles are functionally depleted of glycogen, the carbohydrate energy that the body stores. Even at the worst stroke, the muscles are not completely empty of glycogen, leaving between 10% and 30% of the original supply.
However, the shortage of available energy means that the muscles cannot continue to work effectively. When you're forced to stop exercising after completing very high-intensity sessions of less than an hour, it's usually not glycogen depletion that limits your exercise. While there doesn't seem to be full consensus on exactly how low your glycogen stores can fall before a hit takes full effect (what constitutes the exact point at which it explodes is, at the end of the day, something of a subjective call), Bob Murray suggests that performance will certainly be affected when drops below 50% of stores and is massively committed to 25% in this excellent podcast on the subject. If sex continues, so does the likelihood of confusion and inability to function physically.
This article states that when anxiety is low, for example in training, physiological arousal (increased heartbeat, sweaty palms, butterflies in the stomach) will interact with performance in an inverted “U” shape, that is, the more physiologically excited an athlete is, the better his performance will be to a certain point where it will decline as gradually as it rose. Whatever you call them, they stink, so I've put together a guide to what happens to your body when glycogen runs out, with some practical tips on the different things you can do to prevent it from happening again. Poor Mark was, at the time, suffering with a severe 'hunger floor' - sometimes called a 'bonk' or 'hitting the wall' - because we had been riding for several hours and his body had started running critically low on stored energy to supply his working muscles. A study by Dan Benardot, researcher and author of Nutrition for Serious Athletes, suggests that mental fatigue can trick the body into feeling tired, with evidence showing that participants who claimed to be exhausted had a lot of glycogen in their muscles, so technically their muscles shouldn't have been tired.
Slow contractions are what you want primarily for endurance; you use a higher percentage of slow-twitch muscle fibers the more aerobically you are. The details of carbohydrate loading protocols are hotly debated (and should be considered somewhat individual), but they basically boil down to significantly increasing the total amount and% contribution of carbohydrates to your dietary intake in the 2-3 days prior to the competition, while observing a drop in your load of dressage. As funny as it sounds, sex is actually very serious and it's what cyclists and other endurance athletes call hypoglycemia. Physiologically speaking, a stroke occurs when glycogen stores are depleted to the point where they can no longer adequately supply working muscles with the fuel needed to produce energy or maintain blood glucose levels.
That said, a little one-on-one experimentation is basically what you need to do here to learn what works for you depending on the sport and the event you're doing. .