His owner and lesson riders are mostly kids who let him wonder around with head in air and loose reins and do whatever he wants to do, so the fact of me asking him to actually work really upsets him (to the point he bucked yesterday trying to resist).So my question is will I really learn something on such a horse? I'm not afraid of bucking nor I going to let him do whatever he wants to, but given the fact I ride just once a week I highly doubt he'll develop those muscles. And I don't feel very confident to jump a horse, which doesn't have a balance or muscles for that. Or it's still OK and that's how you learn to jump? I'm fairly inexperienced with lessons, so have no idea if it's a norm.