There's a problem with athletic explosive training now days, all too often it's too much sizzle and not enough steak when it comes to measurable results. There's the truck tires (sports trainers and speed coaches love those truck tires), kettlebells, heavy ropes, and plyometrics all promoted to help with explosiveness in sports. I'm not here to say that those items are bad because they do burn calories but as it relates to building explosiveness, athletic ability, strength, or muscle size they just don't live up to the hype.
There are 6 main things that govern our physical ability: skill, flexibility, body proportions, muscle strength, cardiovascular condition, and neurological ability. All these items are important but two of them you can't do anything about. These would be body proportions and neurological ability. Body proportions which is how your body was put together in terms of length of muscles and tendons, insertion points, leverage factors etc. Neurological ability in the most simple explanation is the brain telling your body what percentage of muscles are activated and how fast they work or reaction time. This is an important point because of much of today's explosive training techniques and sports athletic training from high school to the pros is centered around trying to improve the athletes neurological ability. This is something that you're born with, some people have a high ability and some people don't. No type of training such as flipping truck tires, heavy ropes or kettlebells that's going to make an athlete into a Dick Butkus or Michael Jordan. They have the ability to activate a large percentage of their muscles in a very quick and explosive way coupled with perfect body proportions for their respective sports. There's no training for this.
What CAN be done to improve an athletes explosiveness is to increase their power to weight ratio. Your time is best spent getting as strong as needed for your particular sport. Football requires and all around strength as opposed to track which there's not much of a need for a bulky upper body. That doesn't mean that you wouldn't workout the upper body for track, you'd just put more emphasis on the muscles of the lower body. How to build the most power to weight ratio is by doing a brief, intense, and infrequent strength training program as described in numerous posts on fitlike51.com blog. This should be #1 priority in any athletes regime as it's the most effective and safest way to build explosiveness. Then go to the practice field and perform sports specific and position specific drills to perfect your skill level at your activity. I'd put this recipe up against any program in the world that claims to improve explosiveness through parachutes, kettlebells, plyometrics or any other means.
Muscles are the engine of the body, the bigger the engine the more potential for power therefore the more muscle you build the more explosive power you'll have. If someone is born with a high ability to activate a large % of their muscles and an ability to activate them quickly AND you add a large amount of muscle to them, you'll create a super human. Improving your explosive power by 1% or 2% could mean the difference between making the team, getting the scholarship, or being a champion. The key is to do the right way and not too early in your training program to maximize your results safely.