An easy way to increase speed is to train an athlete to minimize their contact with the ground when working on agility movements. To some people doing repetitive jumping drills may seem pointless, but what they are actually doing is forcing the athlete to decrease the amount of time their feet stay on the ground. Check these videos: http://www.soccertoplay.com/futworks.html These videos are great as well: http://www.thesportofsoccer.com/videosubmissions.html