First Lady Michelle Obama comes to Baltimore's Camden Yards today to deliver a message to children that is a familiar mom mantra: Go outside and play.

The First Lady's "Let's Move" program is, in many ways, a more sophisticated approach to the usual exchange between prodding mothers and inactive children. To combat childhood obesity, "Let's Move" wants healthier food served in schools, wants to eliminate so-called food deserts where nutritious food is hard to buy, wants to improve the stream of nutritional information to parents, and, finally, wants to increase physical education opportunities for kids.

But one of its core messages — move your body — is the same solid advice that generations of parents have given their offspring.

Increasingly, the traditional reply kids have given their parents — that there is nothing to do — has some merit. Times have changed from the days when parents could simply shoo their kids out the door letting them roam the neighborhood, knowing that a network of adults would keep their eyes on them. These days the adults are at work and the streets not always that safe.

Even if the old neighborhood sandlot ball field is still there, it might have health hazards.

It is welcome, then, that Major League Baseball is teaming up today with the first lady to announce a program that will give kids more venues and chances to play baseball. It also matters that the Players Association is taking an active role in this effort. Kids look up to professional athletes, and the first lady is wise to tap the fond feelings youngsters have for major sports stars. As part of today's proceedings, 50 young baseball players, boys and girls, from the Baltimore area are scheduled to work out with members of the Tampa Bay Rays and the Baltimore Orioles.

Exercise, as the first lady points out, need not be limited to competitive sports. Playing a game of freeze tag, or playing catch in the backyard or alley, gets both parents and kids off the couch. It might not deliver the thrill of hitting a home run, but it is a jog in the right direction.