What causes the condition/state of "tying up" during a race? For example, if you go out too hard and die at the end of an 800, mile, 3k, 5k, etc., what is it physiologically that causes someone's stride to shorten and their pace to slow NO MATTER HOW mentally tough or determined they are?
Basically, what causes the body to "override" the minds of even the toughest runners and force their pace to a crawl?
is it lactic acid?
The traditional answer has been lactic acid, but I know there are some new guys who say that is a myth.
The biggest reason is that you are undertrained to race at that pace. Try to add some longer intervals to build strenght and run a smarter race.
It's likely that the racer in question didn't eat enough carbs at the carboload party.
metabolic acidosis.
but what if you have a large mileage base (but little/no speedwork)? would you theoretically "lock up" at a slower pace?
for example, say you were running a 2 mile and your goal was 9:20. you had done lots of mileage at ~7:00 pace but no speedwork. would lactic acid (or whatever people say it is now) flood your system at a slower pace than if you had done pace-specific workouts, thus causing you to tie up despite your endurance?
Lactic acid is the physiological reason for you to slow down. But that is because you have surpassed your lactate threshold. Thus, flooding your muscles with lactate so fast your body cells cant metabolize it and it eventually blocks the neurons from traveling to the musce fibers to fire the muscles. Very basic explanation.
What are musce fibers?
rweas wrote:
metabolic acidosis.
Correct. It's actually not the lactic acid. It's the acidosis created by a H+ hydrogen free radical thrown into the blood as a byproduct of using the anaerobic energy system. This acidity makes the muscles lose their efficiency and ability to contract and retract quickly.
Two Miler wrote:
rweas wrote:metabolic acidosis.
Correct. It's actually not the lactic acid. It's the acidosis created by a H+ hydrogen free radical thrown into the blood as a byproduct of using the anaerobic energy system. This acidity makes the muscles lose their efficiency and ability to contract and retract quickly.
and what would be that byproduct? Could it be lactic acid? Lactic acidosis is a type of metabolic acidosis.
I have seen this at the end of some XC races, those guys just like jogging to the finish line, its painful to watch, you feel bad, this has only happened a couple times to me personally, good topic of discussion
I really hope none of you are adults. It is 100% not caused by lactic acid. You think evolution would devise an alternate energy system that produces a byproduct that paralyzes the individual?
Depleting oxygen used in the making of Adenosine triphosphate (ATP). ATP is no longer provided to operate the SERCA pumps in the membrane of the sarcoplasmic reticulum, which pump calcium ions into the terminal cisternae.[1] This causes calcium ions to diffuse from the area of higher concentration (in the terminal cisternae and extracellular fluid) to an area of lower concentration (in the sarcomere), binding with troponin and allowing for crossbridging to occur between myosin and actin proteins. [2]
Unlike normal muscle contractions, the body is unable to complete the cycle and release the coupling between the myosin and actin, creating a perpetual state of muscular contraction
sdfdfs wrote:
I really hope none of you are adults. It is 100% not caused by lactic acid. You think evolution would devise an alternate energy system that produces a byproduct that paralyzes the individual?
Depleting oxygen used in the making of Adenosine triphosphate (ATP). ATP is no longer provided to operate the SERCA pumps in the membrane of the sarcoplasmic reticulum, which pump calcium ions into the terminal cisternae.[1] This causes calcium ions to diffuse from the area of higher concentration (in the terminal cisternae and extracellular fluid) to an area of lower concentration (in the sarcomere), binding with troponin and allowing for crossbridging to occur between myosin and actin proteins. [2]
Unlike normal muscle contractions, the body is unable to complete the cycle and release the coupling between the myosin and actin, creating a perpetual state of muscular contraction
I think that is called rigor mortis. The utility of lactic acid from an evolutionary perspective is that it is a stop signal for the muscle before this ever happens. lactate can be recycled by the liver and made into glucose, which can be used by the muscle to generate ATP for your precious actin-myosin interactions. This can be repeated in a cycle. So lactate is actually useful up to a certain point, the point at which it can't be cleared anymore by your liver
sdfdfs wrote:
It is 100% not caused by lactic acid. You think evolution would devise an alternate energy system that produces a byproduct that paralyzes the individual?
Unlike normal muscle contractions, the body is unable to complete the cycle and release the coupling between the myosin and actin, creating a perpetual state of muscular contraction
Yes, I am not a complete expert on the chemistry, but lactic acid is not the cause of the muscular "rigor mortis". There is a positively charged ion produced by the anaerobic glycolysis as well as lactic acid. It has been determined that the associated acidosis with the buildup of these ions is the cause of lockup, not lactic acid. Lactic acid is simply recycled by the body and used as fuel.
I recall reading about some experiment where they injected the test subjects with lactic acid during activity. It was as if nothing happened, and the test subjects actually showed a slight increase in performance after the injection.
So, as stated by the above poster, it is 100% not caused by lactic acid.
Depends on the distance