Universal Law for Physical Exercise Method Efficiency:
"The efficiency of any physical exercise method, is the percentage of its motion resistance force, that only causes the intended result"
Craig Wise, 2000
Engineers calculate the efficiency of devices powered by external energy, by measuring the percentage of that energy, that only provides the intended result.
Without the external motion resistance from exercise methods, muscles could not exert hard enough to build strength. So this engineering principle would also apply to any strengthening method.
Someone may want to argue that physical exercise is powered by muscle effort, however that is basically the same argument as saying an electric motor, is powered by its strong magnets, or your car is powered by the battery, which sparks its plugs.
This may not sound like a big deal, but after fitness educators apply it to method design, about 20 times (not 20%) more adults over 35, will be able to build powerful fitness, than today.
Since fitness educators laughed at us for trying to teach them this obvious principle, we made it the design objective for the 100s of Non-kinetic methods and devices, that we have successfully prototyped.