[KenWittlief]

spring loading or pre-tensioned is ok this year (the rules for how much energy can be stored in your bot at the start have been backed off this year)

but if your arm is going to be used to go after the chinup bar, its tip cannot extend faster than 10 feet per second - so you cant just have some big piece of springy material that you release and it snaps out - you would have to dampen the rate at which its released somehow.