Answer:
When you don't have proper body alignment, then the curl ups could be too easy or too hard.
This could also cause injury, due to improper stretching of the muscles.
Some tips would be: (<em><u>You may choose any two of them</u></em>)
1.) keep your feet about 12 inches/1 foot aways from your bottom.
2.) Stretch properly before doing curl ups to prevent injury.
3.) Lay on something soft to prevent spine aching/injury.
4.) Instead of putting your hands behind your head, put them in an X shape across your chest. This can prevent neck injury or aching.
5.) Don't let your feet lift off the ground, have a friend hold them down. Never put gym weights on them, as that can cause injury to your feet.
flexibility is the component that is not skill related fitness
I believe that they all effect the production of hormones
