How to get better by doing the least amount possible!
There are a lot of misconceptions on what minimum adaptive threshold is. I will give you a basic definition, then expand from there:
Minimum Adaptive Threshold: The minimum (or optimal) amount of applied stress needed in a specific skill or movement to cause a positive desired adaptation.
So what does this mean? Essentially, don’t do more than you have to, because additional work will not create additional return (see economic principles article here). However, additional work may have many negative consequences following training, including fatigue and excessive DOMS which inhibits the ability to train that area more frequently.
Application of this concept is not easy in spirit. Most research shows that high intensity training will yield higher strength gains in the main lifts as compared to lower intensity training. However, when programming for athletes, there are other goals in mind which research does not account for: skill acquisition, myelination of multiple motor patterns, specialized exercises that can only be duplicated one joint at a time, development of underutilized or important muscles which are not as emphasized in the main lifts. To build an athletic program taking all these things into account, using higher density and lower intensity is one of the few answers.
Over a short period of time, we can develop a squat that is higher using high intensity training. But at what cost? The cost is time and effort. Effort spent seeking higher returns on an exercise, which may not yield a transfer to the field of play; time spent developing those skills that could have been spent on something more specific. This is where minimum adaptive threshold and “optimal dose” become important: training the proper things at the proper time with proper investment of resources. Spending time on 6×3 at 80% on squats will yield a higher return on squat strength than 2×8 @ 70%, but at a much larger investment of time and energy, resources which can be seen as currency, and used on something more appropriate. If the 2×8 @ 70% is sufficient to yield a return, why do more?
There is no magic formula for “minimum” amount of stress needed. But there is a few markers to help you gauge where you are at:
How many sets are you spending and on how many exercises?
What level of intensity are you applying, and how trained are your athletes?
What is the ultimate goal of the training cycle you are in?
What is the ultimate goal for that specific athlete?
Are you applying a stress specific to those goals, both short term and long term?
Most research done on the topic shows that higher intensity strength training leads to greater hypertrophic and strength responses than lower intensity training, even in undertrained population. But there is another hidden cost in “bypassing” low intensity training in favor of more responsive, high intensity training: how will this affect the athletes ability to adapt to future, more intensive training?
Dr. Verhoshansky says “the correct choice and organization of the work loads depends on a thorough knowledge of the functional capacities and physiological and energy systems that determine and athletes specific work capacity, their respective resistance to adaptation.”
Intensity and volume level can be directly determined by what the athlete needs to adapt, and if you consider the idea that continual usage of a program decreases the ability for that program to cause structural and neurological changes, why would you want to tap out the ability for high intensity training to work, when lower intensity training can still cause the adaptation you are looking for? Sequentially building up intensity over the course of an athletes training career will yield must longer and better adaptation, and still allow for the benefits discussed earlier, more time and ability to train other related factors. Some refer to this as hardening of the CNS: using up training resources unnecessarily and causing them to no longer work.