Hi everyone! I brought home a gsp pup around Christmas. He is now 7 months old. He loves running with me while I bike, and we do so 5 days/wk. This works well now, but I’m not sure what to do during the winter. Can’t bike thru the snow and cannot let him off leash on the trail I use. (This winter he was still a small pup, and daily walks were sufficient) Does anyone have tips for exercise during the winter? I do have a large, one-room basement with a concrete floor where I keep some gym equipment. Dog gym?