I don't really know the program, but I found this:
http://www.google.com/url?sa=t&rct=j...64367178,d.b2I
Heart Rate:
Zone 5a 100% to 102% of LTHR _____ - _____
Zone 5b 103% to 106% of LTHR _____ - _____
How to Train With Power (Cycling)
Step 1. Establish your Functional Threshold Power (FTPw). Use the same 30-minute time trial test above for LTHR to determine your FTPw. The only difference is that the average power for the entire 30 minutes is an approximation of your FTPw. This may be done on the road or on an indoor trainer. As with LTHR testing, the more times you do this test the more accurate the results will become since there is a learning curve associated with such an effort. This is best done before starting the training plan. The more times you do this test the more accurate your FTPw will become.
Step 2. Set up your personal power training zones using the following guide.
Zone 1 Less than 55% of FTPw <_____
Zone 2 55% to 74% of FTPw _____ - _____
Zone 3 75% to 89% of FTPw _____ - _____
Zone 4 90% to 104% of FTPw _____ - _____
Zone 5 105% to 120% of FTPw _____ - _____
Zone 6 More than 120% of FTPw >_____
I guess 5a would be 105% to 110% FTP and 5b would be like 110% to 120% FTP?