In football and other team sports, possessing better than average speed and agility can help you break open big plays. Turns out, you can train to improve both qualities. Consider the findings of a study published in The Journal of Sports Medicine and Physical Fitness.
Thirty physically active college aged males were assigned to 4-weeks of plyometric training. All performed plyometric type exercises 3 days a week, and did the same volume as other groups. Some performed traditional box and depth jumps. Others added resistance with elasic bands, which also helped with assisted jumps.
Two days after the last training session, subjects were tested on 10 and 20 meter sprints and took the Illinois Agility Test. Both assisted and resisted plyometrics improved sprint times to a greater degree than traditional plyometrics. Subjects also realized greater improvements in agility with resisted plyometrics.