Answer:
I think golf does not demand high level of physical fitness. A golfer just need be skillful and able to play under pressure. In terms of physical exercise i think he/she just need to do some muscle stretches.
Explanation:
The only thing I can think of is if you have a thermos with cold or hot liquid and it is closed than it is an isolated energy system but if you take the lid off it would be an open energy system since it's losing its temperature.