You people from the figure animation board seriously need to stop making these although they are figure animations, the two are completely different, you should go read the first aid thread or whatever it is then go to the part about spacing, in fact just to save you the trouble I'll explain it to you.
Spacing is the main difference between a figure animation and a stick figure animation, it is what makes an animation look realistic and if you ever want to get good at making these you have to do it.
To space you need to move the joints at a realistic pace - so at the the start of a movement you would only move it about a pixel, then in the next frame you'd move it 2 or 3 pixels then half way out of the onion skin and so on, if you need a more visual look:
|-|--|----|-------|----|--|-|
| = Frame
- = How much you move the stick.
Now of course this wouldn't be the entire animation, you will need o break it up - so if you are doing a SSP the jump preparation would be one part, the the lift off to landing would be another and finally the reaction would be the last part.
Besides that the animation was quite good if you are new but you also need to move every joint in every frame.
Keep going though and you should improve.