Surprise, Ariz. ? Mike Sweeney, whose back problems caused him to miss 146 games over the last three seasons, reported to spring training Wednesday, expressing optimism that he can play a full season.

Sweeney, who reported two days before the Kansas City Royals’ first full-squad workout, ran and played toss before pronouncing that his back is fine.

“I feel great,” said Sweeney, who sat out the last 42 games of the 2004 season because of a herniated disc in his neck. “I feel 100 percent. This is the first time that I’ve felt that way in a long while.”

Sweeney, who hired former Royals’ strength and conditioning coach Chris Mihlfeld as his personal trainer for the offseason, said his training has included new exercises to help strengthen his back.

“The last three or four winters when I was running and taking ground balls I’d get some kind of soreness in my back, but not this winter,” Sweeney said.

But Sweeney, the team captain, said he wouldn’t tax his back by trying to do too much too early in spring training.

“I’m hoping now that I’m a little older that I’m a little more wiser and I’ll ease myself into activities,” he said.

The Royals need Sweeney on the field to bolster an anemic offense. K.C.’s on-base percentage (.322) and batting average (.259) were 12th in the American League and its slugging percentage (.397) was last. Sweeney, a four-time AL All-Star selection, hit .287 with 22 home runs and 79 RBIs last season.