The Science of Better Sports

'Katie! Go to the ball!" "Heather! Pass it! Jessica's open!" "Shoot, Dawn! Shoot!"

If you've watched a brother, sister, or friend play soccer, or if you've played on a team yourself, you've heard coaches bark instructions to help you become a better player.

A good coach will tell you that you don't just use your arms and legs to play. You also use your head. Applying a little science to your soccer may not turn you into a soccer legend like Pel, but it can help improve your game no matter how well you play now.

With a friend, a soccer ball, a stopwatch, a net, and a bucket or other marker you can do experiments that help uncover some of the physical principles behind the sport. Knowing and using these principles can literally put extra kick into your game.

Just ask Joan Roth, a mom and former math professor who confesses, "I'm not a great athlete." But, she adds, when she stopped to look at the science behind the games she played and used what she learned, her performance improved a lot. In fact, with help from scientists at the Massachusetts Institute of Technology in Cambridge, she put together a kit that includes a list of soccer experiments that can help you.

WHEN you kick the ball, for example, does it usually end up where you want it to? No? Try this experiment.

Take a bucket, shoe, or some other marker and put it inside the mouth of the goal, about six feet from one of the uprights. Use that narrow space as your target. Back away from the goal about 10 to 15 yards and try to kick the ball through that space. First, kick with the tip of your foot. Then use the upper part, where your shoelaces are, then the outside edge, and then the inside curve (instep) of your foot. Try several kicks using each method.

Which is most accurate, most often? The kicks using the inside of your foot. Why? When you use your toes to kick, you apply force only to a small area of the ball. If the tip of your shoe doesn't hit the center of the ball, the ball will head in a different direction. Using the top of your foot, you hit a larger area of the ball. But the inside part of your foot, which is curved, makes the most contact with the ball. This gives you the most control and therefore is the most accurate.

But if you paid close attention, you may have noticed that you had to kick the ball a bit harder with the inside of your foot than you did with your toe to get the ball into the goal.

To verify that, stand about 30 yards in front of the goal. Try each kind of kick again, and have a friend with a stopwatch see how much time it takes for each kind of kick to reach the goal.

Why the differences?

Your legs have more freedom of movement when you swing them front to back (toe kick) than they do when you move them from side to side (side-of-the-foot kick). This allows you to kick with more force when you're kicking straight ahead.

So what do you conclude from the results of the two sets of experiments? When accuracy is critical, kick with the inside part of your foot. Because it strikes a fairly large area of the ball, an instep kick will be more accurate. When you need a powerful kick, use the top of your foot, the shoelace part. This gives the ball the best combination of power and accuracy.

HAVING a hard time "trapping" the ball - stopping it when it's coming at you in the air? Have a friend throw or kick the ball at you at a moderate speed.

When you try to trap the ball, keep your head, leg, or body in a fixed position. Now try the same thing again, only let your head, leg, or body move with the ball as you trap it.

Which approach gives you more control of the ball? Moving with it. When the ball meets something hard (you), it compresses briefly, then expands again, bouncing away. When you move with the ball, you absorb more of the ball's impact. It doesn't compress as much and so tends to bounce less.

It's the same idea baseball players use to ensure they catch that shot into deep left center and football players use to catch the quick down-and-out from the quarterback. In each case, once they've come in contact with the ball, they briefly move their hands in the same direction as the ball to reduce the ball's tendency to rebound.

A list of other soccer tips appears on the facing page. Each one has a bit of science behind it. Hmmm. What if Newton had played baseball...?

* Sport-science kits are $9.95, and include cards describing experiments as well as basic supplies for the tests. For more information: ScienceMedia Inc.: 1 Kendall Sq. No. 160, P.O. Box 9171, Cambridge, MA. 02139, or call (617) 642-1133.

We want to hear, did we miss an angle we should have covered? Should we come back to this topic? Or just give us a rating for this story. We want to hear from you.