What are the bio-mechanical principles that cause a "control" or "players'" racket to offer more control than a power racket? How does greater flexibility translate into greater accuracy? Is it because a too powerful racket forces a strong player to hold back, so that the variety of depth and power must be matched to a smaller range of effort -- thus making the differences in stroking speed more subtle? Or is it that all rackets are dead around the perimeter, and therefore the livelier it is at its sweet spot the bigger a difference you get for each inch away from it? Or is it string deformation that causes a loss of directional control, and if your strings aren't going to give then you need more give in the racket to avoid destroying your elbow?