Work refers to forms of energy transfer between closed systems that can be accounted for in terms of changes in the external `` macroscopic '' physical constraints on the system , for example energy which goes into expanding the volume of a system against an external pressure , by driving a piston-head out of a cylinder against an external force .
Work refers to forms of energy transfer which can be accounted for in terms of changes in the `` macroscopic '' physical variables of the system , for example energy which goes into expanding the volume of a system against an external pressure , by driving a piston-head out of a cylinder against an external force .
An exercise physiologist 's area of study may include but is not limited to biochemistry , bioenergetics , cardiopulmonary function , hematology , biomechanics , skeletal muscle physiology , neuroendocrine function , and central and perpheral nervous system function .