| By Mike Mejia

Comic book geeks the world over all remember that famous quote from Spiderman, where Uncle Ben warns a troubled Peter Parker that "With great power... comes great responsibility". Had he been a strength and conditioning coach, however, Spidey's uncle likely would have said something more like "With great power... comes an underlying need for strength and stability". Okay, so maybe this version doesn't roll off the tongue quite the same way, but there's no denying its validity. Because, while it's true that explosive power training can offer young athletes a world of potential benefits, engaging in it before you're physically ready can often do more harm than good.

Anytime you're talking about training to increase power, the word "plyometrics" immediately comes to mind. A popular form of training ever since it was first introduced in this country back in the seventies, plyometrics have more recently infiltrated virtually every type of youth sports setting imaginable... and therein lies the problem. These days it's not uncommon to see kids of various ages, and ability levels jumping up onto boxes, over hurdles and slinging medicine balls around, as well-meaning coaches and trainers coax them to go "higher" or "harder" with each subsequent repetition. So long as these athletes have spent adequate time training to develop the stability and strength needed to serve as the foundation for these movements, have been thoroughly instructed on their proper mechanics, and are carefully monitored to ensure that fatigue is in no way compromising their ability to execute these drills with proper form, this doesn't present a problem at all. I can tell you from experience though, that this is seldom the case.

Young athletes routinely rush, whether of their own volition, or due to the zeal of coaches and trainers, into plyometric training long before they're physically ready. Once they do, breakdowns in form due to weaknesses somewhere along the kinetic chain (think knees that "pinch inwards" upon landing from a jump) wind up swinging the risk/ reward ratio of the training stimulus way out of balance. Factor in the fatigue build up that often results from doing too many reps and sets, often without sufficient rest, and you've basically got an injury waiting to happen. I should mention, however, that not all plyometric exercises carry with them the same degree of potential danger. It really depends on the magnitude of the jump, or more accurately, the landing forces resulting from that jump. Something like a simple line hop for instance, poses a lot less of an injury risk than say, a depth jump from a two foot platform.

So what does all of this mean when applied to a sport like tennis? Obviously, due to all of the quick starts and stops, lunging, bounding and the power required to strike the ball on both serves and volleys, there's no arguing the fact that plyometric training can be extremely useful to young tennis players. So too for that matter can increasing the mobility and stability of the muscles that act on the hips, knees, ankles and shoulders, improving dynamic balance, and bolstering core strength- all of which can, and should be done, long before engaging in any form of structured plyometric training. It really all comes down to making an accurate assessment of your needs. If you are one of those rare young athletes who's devoted the early stages of your training to developing a sound physical base, then plyometrics might indeed help take your game to the next level. The vast majority of those of you reading this, however, would likely benefit from focusing your conditioning efforts on other areas and saving any form of explosive power development for later on down the line.

In part two of this article, I'll be laying out a program containing the types of drills you'll need to focus on to help construct that base, as well as a progression for how, and when to start implementing plyometric exercises for maximal benefit. Until then, heed the modified words of Uncle Ben, and don't rush into anything your body isn't ready for.

Mike Mejia

<p><img width="85" height="85" align="left" alt="" src="/sites/default/files/u12/Mike_Mejia_Web.jpg" />Mike Mejia, CSCS is the president of B.A.S.E. Sports Conditioning Inc., a training company that caters to the unique needs of young athletes ages 12 and up. For more information, call (516) 662-9717, or visit <a href="http://www.basesportsconditioning.com">www.basesportsconditioning.com</a...