One more citation from Tate "The Periodization Bible, Part II: The New Testament - Conjugated Periodization" [emphasis added]
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The Dynamic Effort Method
The dynamic effort method is used to train the box squat and bench press. This method is defined as lifting a non-maximal load with the greatest speed possible. This method should be coupled with compensatory acceleration. This means you must apply as much force as possible to the barbell, i.e. pushing as hard and as fast as you can in the concentric phase of the lift. If you squat 700 pounds and are training with 400 pounds, then you should be applying 700 pounds of force to the barbell.
The weight used should be non-maximal in the 50% to 75% range. In the text Supertraining, Siff and Verkershonsky state the best range for developing explosive strength in the barbell squat is two-thirds of your best one rep max. Angel Spassov defines this as 50 to 70%. This method isn't used for the development of maximal strength but for the improved rate of force development and explosive force. Let's assume an athlete can only get so strong for genetic reasons. If this lifter has reached his genetic strength potential and has been stuck for five years, can he not get stronger?
I was told at one time that I had reached this limit. I was told this by several university professors in the field of exercise science. What they forgot is that if I learned how to better synchronize my muscles to perform, then I could get stronger by better neural activation. The result was 300 more pounds on my total! This is because at the time I may have only been activating 50% of my absolute strength potential. Through dynamic effort training I was able to activate 70 or 80%. (The percents are used as examples, this was never tested.) This is also a reason why the percent should never be as important as bar speed. Everybody has different motor learning and the advanced strength athlete will activate more than a novice athlete. This is why the more advanced the lifter is, the harder the work is.
For example, if both athletes performed a set of 10 reps in the barbell squat with 80%, the novice would walk away like it was no big deal while the advanced athlete wouldn't be walking anywhere because he'd be on the floor!
If you've followed Louie Simmons' articles over the years, you'll notice how the percents he writes for the squat and bench press have reduced over the years. This is because the gym as a whole has gotten so much stronger and more experienced. The percent for the bench press used to be around 70, now it's around 45 to 55%. Many have asked how this can be. Well, as stated above the athletes are now recruiting more motor units than before so less percent is needed to produce the desired results.
The best way to determine what your training percent should be is to begin with 50% and have someone videotape your bar speed. If you can maintain this bar speed then increase the percent. When the bar slows down then decrease the percent. "