Muscle cells have a large number of mitochondria cells. The reason for this is that muscle cells demand a very high amount of energy to support the movement, exercise, and other metabolic processes. To meet up this demand, the mitochondria cells, which function as the ATP storehouses of cells, are usually in concentrated amounts in and around muscle tissues. This puts the energy needed by the muscles to function effectively within easy reach.
The mitochondria synthesize nutrients taken into the body into ready to use ATP, which are energy stores of the body. The cells are then localized around muscles.