“Good players ≠ Good teachers”
True, and “Observation ≠ Understanding.” And, “Understanding” does not necessarily guarantee quality instruction. Motion capture, 3D graphs, launch monitors etc. show us (more or less accurately) “what happened”. The connection between the data and “how it happened” and “how to change it” relies greatly on individual interpretation.
Erickson’s students succeed because: By intensive study and personal exposure to ball striking greats, combined with years of trial and error, he developed an effective swing model and teaching method which has consistently improved his student’s ball striking.
The “modules” (drills) present components of his technique in a sequence which develops the strength and coordination necessary for the next module. Progress is monitored through online video. There is no social promotion. It takes work, commitment and realistic perspective on the rate of improvement. It’s a serious program, delivered with a high degree of professional commitment.
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I went back and re-read this thread and had a "deja vu"moment, all over again…I was in the last stall at the range (I prefer that one, you're not forced to look at alternative approaches) Two guys set up directly behind me. I didn't look around, but I heard them clearly. One is hitting it thin, fat, shanks, tops and an occasional weak slice. The other guy is striping it, the shaft whoosh is supersonic, ball goes out and up a mile, straight. It falls on the yardage sign with a two yard fade. This goes on awhile. They're chatting, obviously friends, the starter calls them to the tee. As they're leaving I hear the hacker say to the player:
"You're not clearing your hips."