A Naples man was seriously injured when he was impaled by a stick after being thrown from his dirt bike Sunday morning in Sebago.

The Maine Warden Service said Scott Kilton, 32, was riding his bike with friends near 575 Hancock Pond Road on the narrow gauge railroad trail system when he hit a small stump in the trail and was thrown from his bike about 10 a.m.

Kilton landed on a piece of wood that impaled his lower back and abdomen, the warden service said.

Kilton was treated at the scene by the Sebago Emergency Medical Service and transported by air to Maine Medical Center in Portland. A spokeswoman for the hospital said Kilton was in fair condition Sunday night.

The warden service said the riders were equipped with full safety gear, including helmets.

No arrests were expected from the incident, the warden service said.