San Francisco

AMERICAN playgrounds often seem anything but playful. Their equipment is designed not so much to let children have fun as to make sure they don’t hurt themselves. Sure, a simple sandbox and climbing gym are enough to mesmerize toddlers. But what’s to lure older children? No wonder children aged 8 to 12 — the “tweens” — have abandoned playgrounds en masse for instant messaging.

Playgrounds were originally conceived as places to raise future citizens in a social democracy, according to Roy Kozlovsky, an architectural historian, but now they seem geared more toward facilitating easy parental supervision. Well-meaning efforts to reduce the risk of injury have overwhelmed opportunities for self-expression and creativity. The idea of a playground as what Mr. Kozlovsky calls a “pure place” persists, but increasingly, it is also an empty place.

Hope may be on the horizon. We seem to be witnessing, if not a tipping point, then a seesaw tilt in playground design. The slide-swing set-sandbox-seesaw-repeat model is giving way, in some places, to approaches like slickly engineered skate parks, portable performance spaces and do-it-yourself activity centers. Instead of fostering the repetitive motor skills that are essential milestones for a toddler but mind-numbingly dull for a 9- or 10-year-old, these new spaces seek to stimulate the imagination (and the metabolism) by encouraging exploration and free play.