The Front Flip Long Jump

Here you see someone doing a 20 feet (6.1m) somersault long jump. This technique is not allowed in official long jumps due to safety concerns.

Here is an article about the style from before it got banned.

July 29, 1974 The Flip That Led To A Flap The sport's august officialdom is alarmed by a new long-jumping technique that could endanger a few necks—and the 30-foot barrier [...] In contrast, Ecker points out that the flip enables the jumper to take off from the board almost at full speed and at a more desirable higher angle. When he tucks and rolls into a somersault, wind resistance is cut. And since rotation is working with him rather than against him, his feet will land—assuming correct execution—well ahead of his body, and the latter should follow on through so that he does not fall back in the pit. In practice, the hardest part of the new technique to learn is landing. "Wiping out in the flip," Delamere says painfully, "is coming down butt first." To preclude that dire end, the East Germans reportedly have theorized that a half-twist should be added to the flip so that the jumper lands facing the board. Few things in sport prove as easy in competition as on paper, and the flip is no exception. While the dynamics of the new technique may satisfy the laws of physics, the danger factor is at least a worrisome possibility. More...

We will never know if this technique would allow people to jump further than the current record of 8.95m until the technique is officially allowed and the pro jumpers try it. What's for sure, is that it would make the sport a lot more interesting to look at.