Lactic Acid article
- Thread starter Gmonkey
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wastedwhiteboy2
Board Supporter
good article. I always thought lactic acid is what breaks down the muscle so I always tried to get that soreness. I was doing it right but for the wrong reasons.
CDB
Registered User
Is it me, or do they seem to be mixing up aerobic and anaerobic exercise in this article?
Maybe my physiology is off, but type I fibers which are the main ones recruited for aerobic work use triglycerides as their main fuel source, and type IIa and IBB use primarily glycogen and creatine phosphate. Or am I thinking wrong and the glycogen is used for for more prolonged activity and fat as a fuel after that, or the fat used int he oxidation process?
Original Article with emphasis added said:
Original Article said:
Maybe my physiology is off, but type I fibers which are the main ones recruited for aerobic work use triglycerides as their main fuel source, and type IIa and IBB use primarily glycogen and creatine phosphate. Or am I thinking wrong and the glycogen is used for for more prolonged activity and fat as a fuel after that, or the fat used int he oxidation process?
Schwaugher
Member
I'll have to look back in my books, but i thought i remember reading that lactic acid was transfered from the muscle to the liver then turned back into glycogen and transfered back to the muscle. Or something like that.
Schwaugher
Member
This is a section taken word for word from Advanced Nutrition and Human Metabolism. Just posting it for anyone who wants to read it.
The Lactic Acid System
This system involves the glycolytic pathway by which ATP is produced in skeletal muscle by the incomplete breakdown of glucose anaerobically into 2 mol of lactate. The source of glucose is primarily muscle glycogen and, to a lesser extent, circulating glucose, and the lactic acid system can generate ATP quickly for high-intensity exercise. The lactate system is not efficient from the standpoint of the quantity of ATP produced. However, because the process is so rapid, the small amound of ATP is produced quickly and absolutely by substrate-level phosphorylation of ADP. The lactate produced by this system quickly crosses the muscle cell membrane into the bloodstream, from which it can be cleared by other tissues (primarily the liver) for aerobic production of ATP or gluconeogenesis. In the event that the rate of production of lactate exeeds its clearance rate, blood lactic acid accumulates. This lowers the pH of the blood and is one cause of fatigue. Other factors of fatigue include a combination of lactate build-up and the lowering of pH. Under such circumstances, exercise cannot be continue for long periods. The lactic acid system is engaged to provide a rapid source of energy. When an inadequate supply of oxygen prevents the aerobic system from furnishing sufficient ATP to meet the demands of exercise, the lactic acid system will continue to function. Although the system is operative upon the onsset of strenuous exercise, it becomes the primary supplier of energy only after the depletion of CP stores in the muscle. As a back-up to the ATP-CP system, the lactic acid system becomes very important in high-intensity anaerobic power events lasting from 20 seconds to a few minutes.
The Lactic Acid System
This system involves the glycolytic pathway by which ATP is produced in skeletal muscle by the incomplete breakdown of glucose anaerobically into 2 mol of lactate. The source of glucose is primarily muscle glycogen and, to a lesser extent, circulating glucose, and the lactic acid system can generate ATP quickly for high-intensity exercise. The lactate system is not efficient from the standpoint of the quantity of ATP produced. However, because the process is so rapid, the small amound of ATP is produced quickly and absolutely by substrate-level phosphorylation of ADP. The lactate produced by this system quickly crosses the muscle cell membrane into the bloodstream, from which it can be cleared by other tissues (primarily the liver) for aerobic production of ATP or gluconeogenesis. In the event that the rate of production of lactate exeeds its clearance rate, blood lactic acid accumulates. This lowers the pH of the blood and is one cause of fatigue. Other factors of fatigue include a combination of lactate build-up and the lowering of pH. Under such circumstances, exercise cannot be continue for long periods. The lactic acid system is engaged to provide a rapid source of energy. When an inadequate supply of oxygen prevents the aerobic system from furnishing sufficient ATP to meet the demands of exercise, the lactic acid system will continue to function. Although the system is operative upon the onsset of strenuous exercise, it becomes the primary supplier of energy only after the depletion of CP stores in the muscle. As a back-up to the ATP-CP system, the lactic acid system becomes very important in high-intensity anaerobic power events lasting from 20 seconds to a few minutes.