Amar’s The Human Motor is extraordinarily precise in dictating how a worker should position themselves while working. After all, this was the era of Frederick Winslow Tayler and scientific management. Such dogmatic instruction now seems a little crazy — position your feet at exactly 68 degrees! — and it would certainly put a damper on worker motivation and engagement. However, there are corollaries in teaching and learning craft technique.
Most people hate to be told how to accomplish a task in such excruciating detail, yet several bookbinding teachers I’ve encountered have a dictatorial style which embodied this “one right way” approach. Is our musculature (and ability to manipulate it) so much the same that there is only one right technique to accomplish a specific task? Traditional craft does usually have a very specific end product ideal, so it makes sense to follow exact procedures to achieve exact results. Considered optimistically, traditional techniques have undergone a Darwinian type evolution, resulting in efficient production. The downside of this results in people unthinkingly replicating the techniques they were taught, irrespective of the results.
There is a difference between being told how to do something, and learning how to do something. Learning styles vary: some of us are experiential learners, some didactic learners, and sometimes it varies with the task to be learned. Trying and possibly failing with a variety of techniques can teach us a lot about craft, and often not just the project at hand.
Granted, there are easier and harder ways of doing most craft actions. This is possibly one of the most common reasons for taking a class or workshop: to learn easier ways of accomplishing a craft action. Learning one successful way, then branching out and experimenting with others, is often a good foundation. A constant challenge is balancing the workload in able to continue learning with the pecuniary pressures of working efficiently.
Peachey Conservation 
I couldn’t agree more. There are many ways to learn craft, but the more of them you participate in, the more likely your craft skills will be easily adaptable to solving new probems and perhaps encyclopedic in scope.
Yes, I’ve often thought — and try to teach —that a tool based learning is transferable to a wide range of crafts. After all, if you know how to use a handsaw, you can cut wood, plastic, metal, etc….
I spend a lot of time at the vise, filing, sawing, drilling, tapping, etc. The only time in all those tasks that I would surely have my feet in the position shown is if I were push filing from let to right across the length of material held in the jaws. But generally not for sawing, drilling, tapping and most of those other tasks. To attempt to dictate such a foot position to a worker sounds like the worst of a bureaucratic, “professional” mindset. Most craftsmen I know don’t have much patience with bureaucracy, but are usually pretty good at getting things made, wherever or however they stand.