horses going wide on turns

Question
hello sir. may i know why few horses go wide on the turns(bends)? why dont they move parallel to the rail on the bends even though the jockey exercises his steed with great control?

Answer
hi --- going wide on the turns can mean a variety of things that may be bothering the horse when changing leads. like,  a sore mouth or a bad tooth , bad hocks or stifles, a sore back or shoulder, bad feet, a internal bleeding problem all of these things can make a horse make the turns out wide in order to feel more comfortably when changing  leads. thanks  ED HESS