Kicking and chasing after scaled-down balls, about a dozen 3- and 4-year-olds are attempting to learn soccer — or a reasonable facsimile. Some charge ahead with glee, expertly guiding the balls with their feet. Others scoot along hesitantly, their faces masks of intensity.

"Score it in the goal! Score it in the goal!" the coach yells excitedly. One boy nails the goal with a single kick, while another takes three to four attempts. A little girl in pigtails scoops up one ball with her arms and simply drops it into the net.

Such is organized sports for preschoolers. Parents may be crazy for it, but childhood development experts ... less so.

No longer content to wait until their children are 5 or, heaven forbid, 8 (the age most kids start in organized sports leagues), moms and dads are enrolling their offspring in structured programs at the age of 3 and 4.

Such preschool-focused programs, including ones for basketball and T-ball, teach specific skills, general motor development and sometimes concepts such as teamwork — not always an easy lesson for a population whose conversations can consist largely of the word, "Mine!"

Coed classes can be found in parks and recreation programs and private sports organizations across the nation and, coordinators say, enrollment numbers are growing every year. Many programs even have waiting lists.

The environment is mostly noncompetitive (no one wants to tell a 3-year-old she cost the game), but the fact that organized sports have infiltrated toddlerhood doesn't sit well with many exercise and child development experts.

Graduating to training pants, they say, doesn't necessarily signal a readiness for structured programs with equipment and rules and expectations of victory or failure.

EXPERTS NOT CONVINCED

Of course, physical activity trumps sitting around watching TV, says Michael Bergeron, exercise physiologist and assistant professor at the Medical College of Georgia in Augusta. But he says sports lessons might not be the best alternative.

"It might seem innocent to say, 'Come on, catch this, run harder,' but they may be trying to get kids to do things they're not capable of doing, and that leads to frustration and anxiety," says Bergeron, who's also chairman of the American College of Sports Medicine's Youth Sports and Health Initiative. "Kids who are further along developmentally look better than those who are not, and kids can start feeling resentment."

Even having parents on the sidelines watching can put undue pressure on very young children, says Bergeron: "Believe me, a kid knows people are watching him miss the ball. It's different in the backyard — you have dad kicking the ball, acting just as goofy as the kid. Structure is pressure, and it leads to frustration if a child isn't ready for that."

Much of what kids need to learn can be found during free play, says Bergeron — running around a playground, exploring the backyard and playing with age-appropriate equipment and toys.

When play becomes beset by rules, i.e., don't pick up a soccer ball, don't kick a basketball, kids can lose their natural enthusiasm and willingness to try new things.

"What is their attention span?" he says. "Are you asking them to listen and understand beyond what they're capable of doing?"

Crystal Branta, associate professor of kinesiology at Michigan State University, says preschool level is prime time for learning and developing motor skills such as throwing, catching, jumping and running, "But that doesn't mean doing drill after drill," she adds.

Among today's adults, however, many want structure. After all, if they didn't care about specific skills, they could just turn kids loose in the park.

For them, structured sports gives their kids the chance to socialize with other kids, and get a leg up on skills seen as increasingly valuable. "I think parents understand that in school, kids are popular and valuable when they're able to do sports," she says.

Classes for 3-year-olds are easily found via local parks and recreation programs, as well as through some private programs and facilities. The American Youth Soccer Organization, a nationwide nonprofit group that sponsors soccer programs, knocked its starting age down to 4 years old from 5 years old in 2004.

FUN INTRODUCTION

National executive director Rick Davis thinks 4-year-olds have the mental and physical capabilities to begin to learn soccer skills. And it's not really soccer at that age anyway, he insists. "We're introducing them to the sport in fun ways, from simple motor coordination things like walking around the ball to kicking and shooting and passing. If you were a soccer coach, you wouldn't be sure you were seeing a soccer practice."

Yet AYSO's Under-Five program has an entire page of rules and guidelines on its Web site for three-on-three games, where it says, "The two goals of the program are to allow the players to enjoy the activities and to let the game be the teacher." Headings include, "The Start of Play," "The Kick-off," "Ball In and Out of Play" and "Fouls and Other Stoppages."

Part of the decision to start kids at age 4, says Davis, came from parent demand.

But business also factored into the decision. "A number of other programs were reaching down to kids younger and younger, with other activities, and we felt that we were not providing a similar soccer experience," he says. "If these kids go to basketball and have a wonderful time, they may never decide to give soccer a try."