my pony looses shape really quickly, she looses muscle and gains weight!
but what i do when i give her a spell is walk and a little trot for 20mins 3 days in a row,
then a break,
then walk trot 30mins with a little canter for about 5-7 days with a break or two in between,
then walk trot canter and maybe a little crossbar jump, just for the hell of it. for about 4 days
then cause shes a barrel racer, i walk trot around barrels and a little canter, working on the correct line etc,
then by then it's hard to stop her from doing a flat chap around the joint... so after all that i then do a full canter with a faster canter home around barrels... and yeah, then she is pretty fit...
also with the walking trotting and cantering i go up hills and over rough terrain etc. heaps of trail riding, keeps there mind occupied.
also of course warming up properly and cooling down etc.! (: and shes 13years old (: