For the vertical jump, players stand flat footed, and their vertical reach is measured. A series of flags are hung above a player's head, and the player jumps as high as he can, trying to touch as high a flag as possible. The difference between the highest flag reachable while standing and the highest flag reachable at the end of the jump is the player's vertical jump measurement. Each player gets 2 attempts.
While the vertical jump may not make a big difference in a player's draft status on its own, it can sometimes predict a dominant pass rusher of the future. The second best vertical jump in Combine history, Cameron Wake's 45.5 inches in 2005, is a case in point. Wake went undrafted in 2005 and spent 2 years in the CFL. He signed with the Dolphins in 2009, and has since recorded 51.5 sacks and 3 Pro Bowl appearances. Therefore, a good vertical jump performance can sometimes point to a potentially explosive player.
The Broad Jump measures similar levels of explosiveness, and when combined with the vertical jump, can point to a player with high lower body strength. Basically, players start flat footed, and jump forward as far as possible. Players are able to fall forward or land flat footed at the end. If they fall backwards, the jump doesn't count.
These drills are useful in that they can measure a prospect's physical explosiveness in short bursts. If a player has a high vertical jump and a long broad jump, chances are that they'll be successful pass rushers, for example. While the 40 is often viewed as the marquis event of the combine, the jumps are often more useful in measuring a player's explosiveness. While the 40 is important for CBs, who might be burned by WRs with a far better 40 time than their own, the jumps are useful for all position groups, who need some semblance of short distant burst.
While the vertical and broad jumps are often overlooked, these are some of the more important events in the draft from a scouting lens. While a dominant performance in these events won't secure a prospect's standing on its own in my book, it can go a long way towards confirming an already strong evaluation of a player if they perform as expected in these drills.
Don't overlook the jumps at this year's combine. Pay attention to these numbers, they do have at least some relevance. For example, in 2008, Chris Long finished second in the both the vertical and broad jump behind Vernon Gholston. Long has matured into a solid NFL Defensive End. In 2011, JJ Watt dominated both drills, finishing first in the vertical jump and second in the broad jump. . Allen Bailey, D'Aundre Reed, and Cheta Ozougwu were the next 3 best performers in 2011 in the Verticle, with Robert Quinn and Aldon Smith Rounding out the top 6. Robert Quinn was slightly lower in the Broad Jump, but Aldon Smith outperformed Bailey, Reed, and Ozougwu. The top performer at D-End in the Broad Jump in 2011 was Ryan Kerrigan, another solid player. Clearly, these drills have some level of relevance, especially among pass rushers.