Sources of ATP include the phosphorylation of ADP by creatine phosphate, anaerobic glycolysis, and oxidative phosphorylation of ADP n the mitochondria.
Muscles use energy to contract.
ATP
fat
ATP
A single muscle cell is called a muscle fiber.
fiber does not supply energy to humans , as it is not digested by humans ,the reason being that humans do not have enzymes that can digest fiber .
Since the mitochondria produces energy and the muscle cells are part of the mitochondria, they use the energy so they can move the joints.
It is not the muscle but the muscle fiber which works for when recruited for long duration. The red muscle fiber or the slow twitch fiber gets recruited for long term stress on the muscle for example if you do bench press on heavy weight explosively for 5 reps you extensively use fast twitch fibers but if you do bench flys for 15 reps in controlled fashion, you extensively use red fibers.
Myofibril
make more muscle fiber
a muscle fiber
muscle fiber
The smaller fiber in a muscle fiber is called a myofibril. A band of tissue that connects bone to bone is called a ligament.
The sacromere with the proteins actin and myosin allow the muscle cell (fiber) to contract.