That lion is AWESOME! Those are some major muscles showing through. WOW!
As for exercise - I just followed Denna's lead... we did most of our workouts in the back yard as play, but we did start walks around the 'hood pretty early - but only as far and fast as she wanted to go. Early on, that meant maybe 10 minutes down to the end of the block and back. By 1 year old, she wanted to jog 1.5 miles (her easy trot, my jog). Yesterday in the "heat" of 72F at 11am (Seattle area)... she started drooping at about the 1.2 mile mark... and that was a walk in forest shade with her off leash... so, the season definitely plays a part with Denna (EM).
She got hosed off when we got home, with a fresh baby pool to wade in... which always perks her up.
I do try and get as much off-leash dirt/grass walking as we can, with less hard pavement structure - we have some trails around the 'hood that are good for that.
We have a flirt pole... but I have a hard time getting it going straight long enough... she always takes hard, sharp turns to keep up with the target... and that makes me nervous. I can just see her hind end slipping out on one of those turns at a bad angle... she's good when she catches it though - makes me think I'm lunging and horse around me in the yard. HA!