Muscle Glycogen Synthesis after Exercise : an …

Glycogen synthesis is, unlike its breakdown, endergonic—it requires the input of energy

Muscle Glycogen Resynthesis and Bodybuilding by …

Although the rate of CHO incorporation into muscle glycogen storage begins to fall at 2 hours, there is a in the range of 1.5 grams of CHO per kg body weight during the first 2 hours post exercise.

This promotes greater glycogen depletion in the fast-twitch fibers, which have a higher level of glycogen synthase activity than slow-twitch fibers.

Muscle Glycogen Resynthesis and ..

Epinephrine, the major acute stress hormone that signals though the β 2 adrenergic receptor, a G-protein coupled receptor induces the activation of muscle cell adenylyl cyclase, which, in turn, activates cAMP-dependent protein kinase (protein kinase A), which phosphorylates and activates glycogen phosphorylase kinase. The active phosphorylase kinase then phosphorylates glycogen phosphorylase, converting it from the inactive, tense, "b" form" to the active, relaxed, "a" form. By this mechanism, epinephrine induces the breakdown of muscle glycogen to supply muscle cells with a boost of glucose as a ready source of energy to respond to the stress.

Nerve impulses that cause muscle contraction 'induce the release of Ca2+ from the sarcoplasmic reticulum. This Ca2+ activates calmodulin, a modifier protein that binds to glycogen phosphorylase kinase and converts it to the active form without it becoming phosphorylated. The activated phosphorylase kinase phosphorylates glycogen phosphorylase, conveerting it to the active, relaxed "a" form. The active glycogen phosphorylase catalyzes the phosphorylization of glycogen to supply glucose as a source of energy for the ensuing muscle contraction.

Muscle Glycogen Synthesis When Caffeine and Protein …

All three activated protein kinases phosphorylate and inactivate glycogen synthase. Glycogen phosphorylase kinase phosphorylates inactive glycogen phosphorylase b, converting it to active, glycogen phosphorylase a. Glycogen synthesis (glycogenesis) is inhibited and glycogen breakdown (glycogenolysis) is activated.


It was mentioned in the The Neuromuscular System Part I: What A Weight Trainer Needs To Know About Muscle article that muscle cells have many nuclei and other intracellular organelles. This is because nuclei are intimately involved in the protein synthesis process (don't forget, actin and myosin are proteins), and a single nuclei can only support the manufacturing of a limited amount of protein. If muscle cells didn't have multiple nuclei they would be very small muscle cells indeed. So if a muscle is to grow beyond its current size (i.e. synthesize contractile proteins - actin and myosin) it has to increase the number of nuclei that it contains (called the 'myonuclei number'). How does it do this?

Biosynthesis of Glycogen, Starch, and Sucrose - …

They did point out that protein in a recovery drinkmight provide a benefit in jump starting and maximizing muscle protein synthesis and repair of the injury thatcan occur with repeated bouts of high intensity exercise, a particular concern if one is intensely trainingor participating in a multiday event.

Postexercise Recovery — Proper Nutrition Is Key to …

The author suggested that a protein-CHOmix might be help with glycogen re synthesis ONLY in those rare times that adequate carbohydrates are not available in the immediate post exercise recovery period.

05/01/2018 · November 2013 Issue

1. Ivy JL. Regulation of muscle glycogen repletion, muscle protein synthesis and repair following exercise. J Sports Sci Med. 2004;3:131-138.