Every day after work dressage rider Carol Riegel drives to her boarding stable in West Chester, Pa., and assembles a tiny round pen within one of the spacious paddocks. She outfits the pen with a water bucket and a hay net, and then it’s ready for her horse, Rhode Show, to spend the night.

"Ben," an 8-year-old Hanoverian gelding, is on stall rest–a "controlled exercise program," as veterinarians call it–recuperating from a torn right front palmar abaxial ligament. The stall-sized round pen enables Ben to see and hear his barn buddies when they are turned out at night, "and to think he’s being turned out, too," Riegel says. (She moves the pen daily so it’s over fresh grass.)

The rest of the time Ben is either confined to his stall or being hand walked, another facet of his veterinarian-prescribed rehabilitation program. Riegel’s veterinarian, Celia Goodall, MRCVS, Dipl. ACVS, co-owns Sports Medicine Associates of Chester County, in Kennett Square.

"She wants me to do 40 minutes (of hand walking) twice a day, but I can’t manage that," says Riegel wearily