This is a big depends. I have had both - coaching with and without a power meter by different coaches. Both were successful. I suggest interviewing coaches and question them about their program. The key issue is that the coach is interested in your goals (not his), the program is tailored to you and you do the work. The measurement method is secondary. IMO, power meters are the best way to communicate with your coach and have he / she set training objectives and daily prescriptions to meet your goals. Currently I have power meters on my road and TT bikes but not my track bike. We use speed and lap time at the track recorded by my Garmin and uploaded to Training Peaks. Also, I provide a qualitative assessment of the training session based upon how I felt and perceived effort along with the power files. A power file does not tell the coach how you felt hitting those numbers.
Last edited by Hermes; 07-22-10 at 11:27 PM.