Riding my OTTBs trot...help!?

So, I have a gorgeous OTTB whom I love. He's just awesome (IMO LOL). Sweet, kind, smart, gentle...but has the worst trot in the world to ride.

He has a nice long back, long legs, high withers so a nice long stride...that is very verticle. *shudder* I can't ride it for more than a dozen strides unless I "sit" it in sort of a half-seat. Posting it is impossible for me as it just throws me off so badly. Sitting it is a joke too. He has almost no topline..he's gaining weight and muscle but its taking a while.

Do you have any suggestions on helping me learn to ride his trot in a ballanced mannor? I can trot him down the length of the arena in my half seat position, but that's about it. I worry about hurting his back if I go any further.

How long have you had him? I remember my first ride on the OTTB I had, I have no idea how I didn't fall off. I couldn't post/sit/anything the trot for a couple of weeks after I first got my guy, I would have to do five or six strides then go back to the walk to get myself collected and settled back into the saddle. His trot was exactly the same as it sounds your guy is. It got better as he started to learn collection, but it was just something I had to get use to, after adjusting I learned to just love it because of how amazing he looked when he collected up and then extended his gaits.

He's 5.5 months off the track, and I've had him 4.5 months...riding him about 2 months (off/on). I've not ridden him for the past month due to oppressive heat/humidity, torrential rain, and shoe issues...but we're back to riding again. I rode an appy today and posted her trot fine, and found it quite comfy...so I was reassured that it isn't just me. My friend who rode him had the same problem, but being less experienced she kept gripping with her knees, loosing her center of ballance, legs sliding back, and having to pull him up. (she loved it, though, b/c he's gentle but showed her her "flaws" so to speak). I'm just getting back into shape after a 10 year hiatus from riding to enlist, get married, and have children...so I know part of it is me. Thankfully I have an excellent foundation and thank my trainer silently every time I ride (she was a stickler for correct position) but it's still super hard and was wonedering if a) I'm alone b) any tips for help him and helping me. Any tips for helping him to collect? I just need to learn to stay on securely before thinking of that. At a walk I've been working on that, but he's so stinking bored w/ a walk that I can't get him to stay focused enough to walk a straight line. A trot, he loves it. He doesn't rush, stays calm...but is alert, attentive and could trot all day long.

When I first got Buzz his trot was the worst to post to I went all over the place, I was amazed any one could post to it.
But after a while I don't really know what I did I just got better, and now I can't believe I could never post to it.
It will just take time :)

Just keep on practicing! My event horse is a new zealand thoroughbred, never raced or anything. But he has a HUGE trot. Especially his extended trot. Whenever he gets excited he breaks out into an extended trot. The first time he did this with me all I could do was get in a two point like you said. I almost bounced right off! But after a few weeks I could post it just fine and after a few months I could sit his extended trot perfectly. You'll get used to it!

Classic chicken and egg syndrome. You can't sit his jackhammer trot, but the only way you can improve it is to further develop it. I can suggest a little shortcut, although it's more a good training aid that happens to improve a trot more quickly. Your horse's trot sucks because he's still unbalanced. Once he's more balanced, his trot will be more smooth and you'll be able to post or even sit it, although don't hold your breath on that last part. I still can't sit my TB's trot. Anyway, you can improve balance by, unfortunately, trotting. Here's the catch. Take him out into a field in somewhat sloping ground. Nothing dramatic, just not pancake flat. I see you're in Florida so that might a problem. Anyway, get up in your half seat and trot him all over the place on the uneven field. The slight up and downs of the terrain will allow him to build up all the little ligaments and muscles that control his balance. Within about 2 weeks of doing this, I can pretty much guarantee you a better trot in the ring. Trot is all about balance. One gives you the other. Good luck.

I ditto what MyBoyPuck said! I have an OTTB, retired in march. I have been taking him into a grassy field with slopes and different footing. I set into two point and trot and canter him in figure eights, up hill, down hill. Within weeks his trot was smoother and felt MUCH better. Also, I have been walking him on trails with slopes and logs to step over.

Finally, put some poles on the ground and get him to trot those. It forces him to engage his back end and collect better.

Yess, Practice makes perfect :) And just to reinforce what everyone else has said: gaining muscle is your key here. Double pad him if you're that worried about hurting his back. Also, if you're able to ride another horse with a more stable trot, practice working without your stirrups (If you're able to, don't do anything you're not comfortable with) to work YOUR legs, and build muscle for you, too! Practice bending, if you can and know how!