Beijing 2008

As per long jump achievement you need a full power bar on the approach, perfects for the hop and the skip and a 45 degree angle on take-off.

Also, you can get your athlete to clap in rythum with the crowd but as far as I can see this does not improve the little fellas performance.

In addition to the solution above here's a video showing you hows it done. All credit goes to deckdizzle for this video.
Hope this helps and good luck.