Regulation of glycogen resynthesis following exercise.
Tweet Many students find the concept of lactate threshold or OBLA difficult remember that they are different! A threshold is a level above which things can rise. Think of a pain threshold or a wages threshold. Lactate threshold is similar. Another area that appears to confuse is the relationship between lactate threshold and VO2 max.
The breakdown of the energy substrate glycogen is called glycolysis. During glycolysis, glycogen is first converted to glucose and then broken down to pyruvate. This process takes place in the sarcoplasm of muscle fibres and does not require the presence of oxygen; it is an anaerobic process.
Hence the process can be called anaerobic glycolysis. This process is the primary source of energy and ATP when exercise continues at a high intensity for a period of 10 or more seconds. In this energy system, the partial breakdown of glucose to pyruvate provides the energy for some ATP resynthesis.
But when the demand for energy to resynthesise ATP exceeds the amount that can be supplied by this oxidative means, the pyruvate is temporarily converted to lactate lactic acid. In other words, if too much pyruvate is being produced, not all of it can be broken down aerobically, and some is converted into lactate.
The energy system involved is sometimes called the lactic acid or lactate anaerobic system. The lactate being produced first builds up in the muscles, but then diffuses into the blood.
Lactate sampling of blood is one way that levels of exercise intensity and correspondingly, fatigue, can be measured. Because the harder you exercise, the more you use the lactate anaerobic pathway to resynthesise ATP, and hence the more lactate that is produced in your muscles and diffuses into your blood.
High levels of lactate in the muscles causes fatigue. Probably this is because of the high levels of acidity due to the presence of lactate, which in turn inhibits the actions of enzymes. When this happens, exercise intensity must be reduced or stopped to allow the body to remove the excess lactate.
Another limitation of this system is that only a relatively small amount of ATP can be resynthesised from anaerobic glycolysis. The lactate anaerobic system is however, important to the athlete, because it provides a rapid supply of resynthesised ATP for energy.
For example, exercises performed at near-to-maximum rates and lasting up to 2 minutes depend heavily upon the lactate anaerobic system to provide ATP energy.
The following diagram summarises the lactate anaerobic system: But the relationship between workload and ventilation rate is not linear, as might be expected. As can be seen, the relationship between ventilation rate and workload changes at about Watts. This upward breaking point equates to the anaerobic threshold, which used to be taken as the point where exercise was becoming largely anaerobic.
But measuring changes in breathing rates is not an accurate method of measuring lactate production. Lactate is not a waste product or, as I have seen in some books, a poison! It is a valuable substrate for aerobic energy.Glycogen restoration rate is higher following glucose feeding as compared with fructose feeding because of glucose's higher glycemic index rating.
Some people have mentioned to me that protein is also needed along with carbohydrates to increase muscle glycogen resynthesis. Many students find the concept of lactate threshold or OBLA difficult(remember that they are different!). I think it’s the ‘threshold’ bit.
Body Building supplements and pills that work and the ones that waste your money, for men, women, and teenagers November 5 by Ray Sahelian, M.D.
There are a number of supplements used for male and female bodybuilding. Because further increases, up to g/kg/h, do not lead to further rise in glycogen synthesis rate, the carbohydrate amount equal to g/kg/h can be considered optimum to maximize the resynthesis rate of muscle glycogen stores during post-exercise.
Sleep & sporting performance - Written by Yann Le Meur (@YLMSportScience) and Christophe Hausswirth (@HausswirthC), FranceMany high-performance athletes are involved in regular, intense training programmes aimed at to stimulating their psychophysiological adaptations in order to improve their capacity for performance.
Flexible dieting, or "If It Fits Your Macros," means counting macronutrient grams instead of calories. Use this calculator to find your ideal ratio of proteins, carbs, and fats.
For decades, the number of calories you ate in a day was the end of the story. Stay in a deficit, and you'd supposedly.