If more than one fish is involved it could signal a severe environmental problem. Make sure you have plenty of aeration and filtration. Sometimes the fish during this activity can be observed rubbing up against objects or the bottom of the pond. Do a partial water change and check your filtration system. If only one fish is involved consideration of an infectious etiology would be appropriate.
Some fish just like to jump.
But, if this behavior seem abnormal it may be associated with the fish attempting to escape it's environment. Gulping for air at the surface of the water. May be due to low levels of dissolved oxygen, high levels of nitrites or gill parasites. Do a partial water change. Check filtration systems.