Fido's still a puppy, but you've got shin splints to spare, and the idea of giving him a good run every day tires you out just thinking about it. Certain "leash free" zones in and around the metro area are the answer, where you can let your dog scamper about unencumbered while you bask in the warm sunshine on the sidelines. The best one by far is on the southeast corner of Cherry Creek State Park, just a few paws east of Parker Road and north of Orchard. Your dog-friendly pup can romp and play with other dogs in the large, enclosed field. Dogs can also swim and cool themselves off in the many pools in the "dog training area." On sunny days, there are sometimes more than sixty dogs using the large space, with children playing beneath a shade tree and doggie parents conversing. For more information, you can bark up the Cherry Creek State Park Web site, www.parks.state.co.us/cherry_creek.