AThis is an excellent question. Horses with hocks that lack angulation are considered "straight," and this is considered a conformational flaw. However, many of these horses are not limited in their ability to perform. Horses with straight hocks do have a somewhat reduced ability to flex the hock joint, but it does vary with the horse. These horses usually are more susceptible to concussive forces; therefore, they might be prone to concussion-related injuries such as osteoarthritis in the lower hocks joints (bone spavin). However, you have to consider the amount and type of work that will be done by this horse.

A horse with straight hocks that is just ridden for pleasure on the trails might never be affected by his straight hocks, where as a Grand Prix show jumper might have recurring problems related to straight hocks. However, there are many examples of top-level performance horses which have "straighter than ideal" hocks (this also goes for other conformational defects).

To answer your question specifically–no, a horse with straight hocks should not be prone to tripping and should not tire more easily, as compared to a horse with more normal hock conformation. But the whole horse must be taken into consideration. The horse should be examined closely by your veterinarian before you purchase him for anything that could cause him problems. When deciding on a horse for trail riding, there are several safety considerations to keep in mind. It is very important to have a horse who is sure-footed and one that does not trip easily. (Some horses with navicular disease can trip frequently from not picking up their feet very far off the ground