Warning: Fly fishing can be hazardous to your health. A team doctor for the Montana Grizzlies has conducted a study that found that out of 150 fly casting instructors, 140 suffered from some sort of pain in a wrist or an elbow. The culprit? Anglers using bad mechanical form to throw the line. The doctor has teamed up with Jason Borger (who's name is always followed by the statement that he was the shadow casting double for Brad Pitt in that movie we all enjoy), and started The Fly Casting Institute as a way to help people cast "healthier and better."
"Patients with small lightbulbs attached to their bodies have the motion of their casts captured by six infrared cameras. McCue can then look at recording of the casts from different angles and find ways to fix problems. A common fix is to teach the patient to use more of the stronger shoulder muscles and less wrist and elbow."
It all sounds pretty high tech to me. I submit that Rev. Maclean only needed a stern look and a metronome and probably didn't really care to hear that your shoulder hurt from too much fishing.