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.
The Pump is the tight, blood-congested feeling in a muscle after it has been intensely trained. Muscle pump is caused by a rapid influx of blood into the muscles to remove fatigue toxins and replace supplies of fuel and oxygen. A good muscle pump indicates that you have optimally worked a muscle group. The greatest feeling you can get in the gym or the most satisfying in the gym is the pump.