Well there is also this
The Effect of the Pessoa Training Aid on Temporal, Linear and Angular Variables of the Working Trot | eurodressage
Sorry can't cut and paste from there
Peasebrook Equine Rehab - About Us
It is impossible to describe all the conditions we deal with as there are so many different presentations especially horses that have suffered a traumatic incident such as a fall or road traffic accident. These cases can have all manner of pain, muscle spasm, dysfunction, muscle wastage etc. Generally speaking the sooner a horse receives treatment after a trauma, the better.
There is no substitute for "knowing what works" but we also incorporate new treatments as they come along in order to evaluate them. There is very little published work on results of different treatments and therapies mainly due to the unique features of many cases, with many variables, making direct case comparisons difficult. This means that one seldom gets enough case numbers with a similar enough profile to be able to apply statistics to the data. Success of a case is judged by elimination of lameness, return to previous level of performance in a dressage horse for example, or number of races completed and level of prize money achieved in the racing industry.
Many of our rehabilitation patients are recovering from back treatments ranging from dorsal spinous process resection to facet joint medication and release of muscle spasm. With surgical cases, wound healing is the initial concern and often we cross-tie horses to prevent them lying down and disrupting sutures. Thereafter we start exercise to prevent unwanted adhesions and promote mobility. Horses with primary muscular spasm are treated in a variety of ways including deep muscle massage, acupuncture, tissue injection and osteopathic manipulation. They then enter a ground schooling program; we use Pessoa and Equi-Ami training aids which encourage the horse to work in the correct outline to promote the right muscle development to support the vertebral column. We also encourage patients to work long and low to allow stretching, flexing and enabling the horse to find a natural balance. Close scrutiny of the horse at exercise allows us to assess symmetry of action on both reins.
We can Cut and paste all day, but the Pessoa type is not hock hobbles, used properly it is not designed to 'sock them in the mouth' Used wrongly it is as abusive as you care to make it, used properly a lot of people find it beneficial.