Relax, relax, relax. relax your seat, breathe out in a big sigh, soften your arms and hands.
talk to him under your breath, saying whatever you say at home to calm him down.
practise shortening and lengthening reins repeatedly at home (e.g. when hacking on roads and when schooling) so that horse does not think shortening reins = go for it. i have done this hundreds and hundreds of times to chill my mare out about walking in the arena!
I had this problem my mare used to jog , so every time she went into trot or jog without command I would stop her with my left rein turn her in and make her wait for a minute , after a while I used to just twitch my left rein (half halt) and she knew it meant come back to walk and if she didnt respect my command she would be made to wait again she soon learnt that the twitch meant SLOW DOWN because i wont tollerate it , this would be very handy in the dressage ring as the twitch only need to be very suttle and she would know what you meant didnt take long for my mare to get it and it still works to this day, keep trying this it really works just need to get the message across , good luck
i think a lot of the time in dressage tests horses jog off into trot because people are overriding the walk if that makes sense?! i.e. they get to a walk section and try to walk really really fast in the hope that this will make horse look better. actually you are better off really slowing the walk down by deep seat and breathing and half halt if necessary and not pushing on with legs any more than necessary. this should improve your walk marks no end as walk will be bigger and longer and hopefully horse won't jog off when you pick reins up. that probably makes no sense to anyone but i know what i am trying to say
That's interesting Diggerbez, it does make a certain sense to me and I'll give it a go myself I think as my mare tends to anticipate and jog, especially when I go from free walk to medium.
KERILLI : I schooled him today and tried what you told me, the thing is when I relaxed and calmed him with my voice he kept on thinking I wanted him to stop and halt !!!!!!, the question of finding the happy medium is proving to be harder than I thought, applying the right amount of go forward aid and comeback aid is quite difficult, but whoever said riding was easy !!!!!!! lol
Any more hints and tips I can try to solve the problem ???
try doing nothing at all! sit there as passively as possible (for now) and just let him walk along underneath you, i think of it as "mooching." don't push or pull, have your legs just hanging by his sides, breathing with him, "like wet dishcloths stuck against his sides" (Mary Wanless image iirc) and legs swinging slightly from the hips as his tummy swings from side to side in walk (you should be able to feel this) and with a nice soft contact on the reins, whether in medium or free walk. if he needs a bit of encouragement, either breathe "walk on, good boy" under your breath or give a tiny push wiht your seat, or swing your legs a tiny bit more from side to side so they give him a gentle nudge. experiment and see what works best... bearing in mind that in a comp situation, at least the first few times, as little as possible might just be the ticket! good luck!