retrolefty:
Well I'm confused. Many do, in disregard of recommendations not to, power their servo via the arduino 5V pin, which can supply maybe 300-400ma and if it's a small enough servo with little mechanical load, not see any apparent problem.
This question is about a high torque servo moving a substantial load. I think it's reasonable to assume that it will try to draw more current than the Arduino's voltage regulator can supply. The usual rule of thumb for small hobby servos is a peak of about 1A per servo. For a high torque servo under load, it might well exceed that.