Our interpretation of weight bearing and what is happening during that portion of the stride sequence is always up for debate. It is so complex that to gather a basic understanding of these individual features we must identify and discuss what has become the center of attention. Knowledge of physics helps to sort out some of the more complex aspects as it is a factual science. There has been research on many aspects of weight bearing but nothing that is as concrete as 2+2=4. Breakover is a good example. Lots of discussion and often without any consensus on the whole process

Relax, we aren’t going to discuss that. Instead, it would be more proper to discuss the initial phase of weight bearing, impact, first. Unfortunately, we have to discuss the final milliseconds of the swing phase to appreciate how the leg prepares for impact.

Figure 1 (above) is just that, a picture of a left front leg ready to impact the ground. The horse is in the suspension phase and the left front leg is preparing to hit the ground by being in a “closed packed position.” That position is the leg becoming a straight line and being held in that position by tension on the tendons attaching at the coffin bone (P3), extensor at the extensor process and the deep digital flexor (DDF) on the solar surface of P3. At this point, the leg has extended to the limits of extension and will be slightly pulled backward in flight…