hammer-throwing 101. reporter: a.j. krueger is a champion hammer-thrower, not really a hammer, a bowling ball on a wire. he gave me a lesson minus the 16-pound ball. with fancy footwork and spins, the goal to throw it as far as humanly possible. forward. forward. forward. forward. forward. where are you? where are you? reporter: next up, the trampoline. it s just jumping, right? a lot of people think that looks easy, i could do that. it is definitely not like that. not your typical backyard trampoline. the trampolines we jump on are much more powerful. reporter: savannah vansant, makes it look easy. even the easiest tricks like