Post-legged horses (1st image) often have a lack of flexibility in their hind legs and stand in an up-and-down “post” position, rather than the desirable slope (2nd image). This can make it difficult for the horse to properly perform lateral maneuvers or collection. 
Excessive Concussion
Post-legged horses may suffer an excessive concussion on their hind feet because their straight legs cause them to stab directly into the ground at each stride, with little flexing action. It can lead to hoof cracking, stifle injuries, sole bruising, or other concussion-related issues. It is vital to address these issues as soon as possible to reduce any further damage or discomfort for your horse.
Increase Risk of Injury
The incorrect hock angle puts extra strain on the flexor tendon and its sheath and the upper portion of the suspensory ligament. It increases the risk of injury due to hard use or exercising when not adequately conditioned for it. Please pay attention to any changes in your horse’s gait or movement so that you can correct any potential problems before they limit performance or become performance ending.
Changes in Movement
If you notice any changes in your horse’s movement, such as stiffness or lameness, make sure you speak with your primary care veterinarian so they can assess what might be causing these changes and provide appropriate treatment if needed. By taking proper precautions and educating yourself, you will be better equipped to keep your horse healthy and active!