If yoda is able to jump and flip around so well...

...why does he have a walking stick? In the OT he was obviously old so he kinda needed it, but in the PT he's jumping around kicking ass and had his walking stick...but doesn't seem like he needs it really

Didn't he invigorate himself with the force beforehand?

You talking EU? ha-son

Nah that's common sense. When he uses the Force it makes his body stronger. Afterall we see ither Jedi use the force to pull of incredible leaps and run at superhuman speeds. Yoda, being the strongest Jedi, should be able to do the same.

Either that, or he just had a five hour energy shot.

with zero calories

To mask himself as awesome. Trick his opponents into thinking he's old and little. Well, that's not tricking, he IS old and little. But that he's fragile, too.