functional training program should prepare an athlete to play for his/her sport, with a strong focus on training movements, not muscles. It’s important though, to maintain a balanced perspective on functional training, and not assume just because an exercise is not performed in a three-dimensional space, it is not functional.
To an elderly client, increasing his/her quadriceps via a may be very functional, simply because they do not initially possess the strength to perform an unassisted body weight squat. Alternatively, we may need to increase lower limb strength using a leg extension or another regressed version of a body weight squat as a means to increase the lower limb strength required to be able to perform a body weight squat.
A body weight squat in most situations would be considered a very functional exercise, but in this case it is not functional at all. Thus, an exercise that is functional at one time might be equally non-functional at another time or under different conditions.