As chicomio- it dependswhat you are training for and how fit the horse is in the first place.
You need to build up in a stepwise progression. Ideally you need a heart rate monitor too, otherwise you are just guessing the stress you are putting the horse under, which can never be as accurate as using an HRM. This also helps avoid under training as well as over training
Ex Showcob needing more fitness to assit with rehabilitation after sacroilliac injury.
She is rideable, hacking and light schooling 5 times per week. But just seems to "get out of puff" easily and doesnt seem to be "keen" and a bit "lethargic about life" - esp in the shool. Just thought if I could improve her fitness levels then she may be more enthusiastic towards her work, (and more like she was before the SI injury 3 years ago).
Canter can still be a bit iffy with her putting in the odd small buck .... but nothing we cant cope with. Walk and trot fine. She is happy enough and looking wonderful - if a smidge fat after the summer.
Want to carry on riding her and ejoying her but sometimes it feels like pushing an elephant up a hill
Just typed a long reply and the bl**dy computer wiped it! AAgh!
So, briefly, just gradually increase the length of time you ride for. As you progress, increase the length of time you trot and canter for. You can also increase the work effort by introducing hillwork and poles, if her injury allows. Warm up and cool down well and intersperse faster work with walking. As you build up the faster work can get longer. Perhaps time it? So you start with ten minutes trotting and then add on a minute, gradually building up to longer periods of trot. Same with canter but start with 2 minutes of canter. Dont up the workload everytime you ride. Do the same for several days then when it seems like she is coping better, increase again. If at any time sh appears to be struggling, reduce the workload and build up more slowly.
Hacking as much as possible, not just work in the school. Shorter periods of work in the school than when hacking because it is harder work. That may be why she seems more lethargic when schooling. Hack with a friend for mre motivation!