The problem with the private training industry, particularly the facilities that work with collegiate and pro athletes, is that they often look to generate the strongest adaptive response in their clients because they have such limited time to prove their worth.
This often leads to the use of novel training aids.
While this may be impressive to the client and who ever is paying for the service it is actually to the detriment of the athlete, in the long term, because of the residual implications of such sudden changes in exercise form, load intensity, and volume.
The very doctrine of most private facilities (the biggest results in the shortest amounts of time) exists in stark contrast to what Charlie stressed over the years with respect to the importance of ensuring the smoothest possible transitions between training phases over the course of the year.