It is absolutely crucial for any athlete, equine or human, to have a good and well balanced posture, this ensures optimal performance in any athletic event. The muscles and joints in the body work in relationship to each other and if any of these relations are disrupted, an imbalance can occur. This will minimise the optimal function of the affected as well as other areas in the body.
It is always important in recurring injuries to try and find out what causes the injury to reoccur, in most cases it is an imbalance that has occurred and is affecting movement and strength in a particular area. This will lead to less effective function of that area.
There are lots of contributing factors that can cause poor posture or form. These can range from overuse stresses, occupational stresses and in some cases there could also be a congenital or genetic cause. Most of these can be addressed and if not 100% fixed it can certainly be improved.
Make sure you carry yourself tall and proud in all situations and it will boost your confidence immensely!