Compare and contrast the curl-up and arm hang test and explain why different tests cannot be used interchangeably.

The curl-up tests the strength and endurance of the abdominal muscles, while the arm hang tests the strength and endurance of the arm muscles. Since different muscle groups are developed and tested in different ways, tests for different groups cannot be used interchangeably because the results do not pertain to the same group of muscles. 

No it doesn’t hurt depending on how many fingers they use

Wash your hands often and recycle your trash instead of just throwing it away.