This is so important! Especially when teaching your horse something new! During training sessions, I'll start with a long and low, stretchy warm up. My 'exercise A' would be something the horse is fairly confident at, like some walk-canter-walk transitions. 'Exercise B' would then be something I'm trying to teach or improve - this doesn't need to strictly be drilled into your horse for 5 minutes - especially if he's finding it difficult. Sometimes I'll just ask for a few steps and then go back to something he's confident in, so I keep him engaged and enjoying his learning :)
'Exercise C' would then be another thing that he's quite confident in, like some lateral work.
The 'spare time' is what I would call 'break time', and I would slot this in between each 'exercise', in the form of a loose rein walk.
The 'cool down' would consist of lots of long and low, stretchy trot and then a loose walk
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