Remotely monitoring performance in sports acoustically

In many sports, a coach will tell you that their trained ear can detect a superior performance. Volleyballs, soccerballs, and footballs all resonate at a characteristic frequency when struck. The resulting sound can be monitored off the field of play to determine how hard they were hit. A simple sound level meter can be easily modified to make a smackmeter. A bit more complicated but perhaps more rewarding is the resonate sound from aluminum baseball bats, or tennis and squash reckets, when can reveal not only how well but where the hit was made. Monitoring the sound of the stumming shaft of a golf club during a swing gives valuable information on swing speed and uniformity. Most every sport, for example, how about the splash of a dive, appears to have sounds that could be worthwhile to remotely monitor, especially given the resolution and speed of modern analysis techniques.