It's good for a cycle through out your training for several weeks(maybe twice a year) while working to improve your power output as an advanced/experienced athlete. However as already mentioned it's very taxing on the body(ligaments/tendons) and CNS so it should be limited to short periods of time.
The complex training relies on Postactivation Potentiation (aka PAP) concept. The principle "is that prior heavy loading induces a high degree of central nervous system stimulation, resulting in greater motor unit recruitment and force, which can last from five-to-thirty minutes"
Postactivation Potentiation
In one study on that same link: "The results of the study found that recreationally trained athletes exhibited fatigue at five minutes following the acute heavy resistance stimulus, and thus no enhanced performance. However, in the athletically trained individuals, the heavy PAP stimulus enhanced power performance at five and 18.5 minutes.The author's concluded that PAP enhances explosive strength performance in highly trained individuals, due largely to their fatigue-resistant, high level of conditioning."
This is the reason why we always tell beginners not to jump into advanced programs. These techniques can cause injury, overtraining, or simply be ineffective for beginning athletes. It often takes years before specific training principles become useful in your strength/athletic improvement and progression. So yes GSP might use this technique with a lot of success but a noob of the net who has never trained consistently will not see the same benefits despite the ease with which beginners tend to make strength adaptations/gains.
