As movement specialists, there is tremendous satisfaction when we are training someone and “it all comes together”. The movement is agile, the sequence is efficient, and the execution is flawless: mission accomplished. Or is it? The body has learned to integrate its resources to accomplish the task in the preferred way. Preferred from our observation standpoint, and preferred from the body’s efficiency standpoint. But what happens when the conditions prevent this optimal coordination? What factors might prevent the successful execution of the task? How can the next phase of training tweak the successful execution to create more robust success?


At the Gray Institute the answers to those questions all revolve around the word “tweak”. When our clients attain task success, the job is not complete. But what should be tweaked in order to create more success. Practitioners of Applied Functional Science (AFS) know that there are 2 broad categories of tweaks: the demands of the task and the resources the body can bring to bear on the task solution. In our Certification of Applied Functional Science (CAFS) there are 10 Observational Essentials that are the variables that can be tweaked. In CAFS, the environment, beginning position and load can be tweaked to alter the demands of the task. Movement driver, direction, height and distance are variables that can either increase or decrease the resources (motion and muscle force) available.


The environment of our training may not represent the authentic environment of the task. The firmness, slope, friction, and material in the real world may be very different. What about the tennis player who might be playing on hard courts, grass, or clay? How different is it for the golfer in the fairway versus the rough, and with the surface potentially pitched in 4 different directions? In volleyball there is an incredible difference in ground reaction forces between the barefoot-sand interaction compared to the shod-firm and flat surface interaction.


During training as load is added to the movement execution strength is built, and when combined with speed, power generation is developed. This is most effective during foundational movements. As the movements become closer to the actual activity (skill), caution must be employed not to use excessive load to the point where the Chain Reaction sequence changes and the proprioceptors become “confused”. The load tweaks will be different depending on whether the load is central to the body (weight vest) versus peripheral (dumbbell in hand).


The beginning position of the feet can have a “double” effect. This means that the task changes when our client starts in a different position, and it changes the position of the joints that alters the motion available and the muscle force that can be generated. In the Functional Nomenclature developed by the Gray Institute, with both feet on the ground there are 27 symmetrical foot positions and 36 asymmetrical foot positions that can be used to alter the resources that the body has available. Which foot position tweak to use will depend on the individual client, the task to be executed, the goal of the training, and the present level of success.

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