T Nation

Where Do Muscles Get Energy


to lift weights or run or do anything?

i know carbs are a good energy source for muscles,but what else is there?


You sound insane, you should be medicated.

What the hell do you think we eat food for? Muscles draw their energy from the food we eat, all of it.




We get energy in the form of ATP. Commonly called the universal energy currency, it occurs in small quantities throughout the human body but can be easily transported to where it's needed. It can be energy yielding, when the terminal phosphate group seperates releasing 30.6 Kj mol-1 or energy requiring when the phosphate combines again. ATP is made in respiration, either in substrate level phosphorylation or as a joint result of the electron transport chain/oxidative phosphorylation/chemiosmosis theory. Respiration relies on biomolecules (carbohydrates = glucose, Lipids/Fats etc.) so that's why food gives energy.

Muscles are striated and have filaments, actin and myosin. The Myosin head attaches onto the actin binding site and rotates it in the sliding filament theory. This causes muscular contraction. The myosin head which attaches to the actin active site behaves almost like an enzyme. Muscular contraction need energy, so it needs ATP, which in turn comes from respiration.


damn are you some kind of scientist?


Not a whole lot of rotating going on in Huxley's sliding filament theory - the thin filaments are sliding over the thick ones, pulling the Z discs behind them and causing the entire sarcomere to shorten. Overall, I'd give you an A-. :slight_smile:

While ATP drives every muscle contraction (specifically in the cocking of the myosin head and cross-bridge detachment stages), our muscles get energy, or metabolize, through three systems - phosphocreatine, anaerobic glycolysis, and aerobic respiration. It's these systems that cater to the energy demands of skeletal muscles during exercise.



And while it differs for various reasons, in general, you can power muscular contraction for 0-4 seconds using the ATP stored in the cells, ~ 10 seconds with the phosphocreatine pathway, ~1.5 minutes with the anaerobic glycolysis pathway, and anything above that draws upon the aerobic pathway. Basically: ATP=one jump Phosphocreatine=100m sprint Anaerobic glycolysis=400m sprint Aerobic respiration=long run.


And if you ever want to actually understand what you've just read here, go take a basic biology class. And pay attention during cellular respiration.



and food.



Or just ask the Google


Crack and 45 ACP rounds to the face. OP, I suggest you start ingesting both.