1 Chemically, ATP is an adenine nucleotide bound to three phosphates. 2  There is a lot of energy stored in the bond between the second and third phosphate groups that can be used to fuel chemical reactions. 3  When a cell needs energy, it breaks this bond to form adenosine diphosphate (ADP) and a free phosphate molecule.
calf muscle pump. calf muscle pump. an action of the calf (soleus) muscles in which the muscles contract and squeeze the popliteal and tibial veins, forcing the blood in those veins to move upward toward the heart. Also called soleus pump.
Muscle Energy Systems. ATP (Adenosine Triphosphate) is a complex chemical compound formed with the energy released from food and stored in all cells, particularly muscles. When our brain sends signals to our muscles to contract, energy stored in the form of ATP is converted into the energy to drive the movement of the muscles. Every muscle cell has a small amount of ATP floating around which can be used readily however this is used off very quickly and must constantly be replenished.