Now that everyone wants to train for youth sports rather than playing sports, plyometrics is a common word in the youth sports vernacular. Everyone is doing plyometrics or thinks they need to be. However, few people really know what plyometrics means.
Derived from the Greek word “pleythyein” (to increase) and “metrics” (to measure), track and field coach Fred Wilt coined the current term in 1970.
To increase and to measure does not explain anything, really. So, what is plyometrics?
“It’s just a fancy word for ‘jump training’,” said Jon Beyle, physical education instructor, and track and field coach at Chapel Hill’s Philips Middle School.
So, if plyometrics is jump training, how does it work?
“A muscle always lengthens before it shortens,” Beyle explained. “For example, if I was going to shoot someone with a rubber band, I’d pull it back. The quicker I pull it back and let go, the better it will fly. If I pull it back and hold it for a long time, the rubber band will lose some of its elasticity, and it won’t fly as far.
“So, it’s not how long you make the muscle, but it’s the rate: how quick the muscle goes from lengthened to shortened. That’s ultimately what you’re trying to accomplish.”
Well, if some jump training is good, more must be better, right?
“You can go on YouTube and see guys doing depth jumps, and that’s incredibly stressful on the body,” he said. “That’s where you stand on a bench maybe two feet off the ground, you jump off and hit the ground, and then you jump right back up over a hurdle or onto another bench. Unfortunately, this is where too many people start with plyometrics.”
“For middle school kids, we don’t want to over train them,” Drexler said, “and we don’t want anybody to hurt themselves.”
Well, if it’s dangerous, should kids avoid plyometrics, even though it is just jumping?
Because of the many repeated explosive movements and the high impact of jumping and landing, trainers aren’t blind to the risks involved.
“We don’t touch plyometrics until we’ve been training for six weeks,” Beyle said of his Phillips track and field team. “It’s the repeated landings that cause so much stress on the body. If they don’t have the strength base, their body’s going to break down.”
So, plyometrics is essentially jump training which uses the stretch-shortening cycle to create an explosive movement. While plyometrics training is safe – hop-scotch is essentially a low intensity plyometrics exercise – high intensity training too early can be dangerous. The key is to progress gradually with a proper base of strength before doing six-foot depth jumps.