15' warm up - nice smooth spinning - then shift into a the big chain ring and into a gear that allows you to spin at about 65-70 RPMs. You will spin 3x25 minutes in this gear - HR should be mid-high Z2 - recovery will be 5' easy between sets - you will probably see HR drift into Z3 - keep the cadence up - this is where you build strength. 10' cool down.
WU: 400 swim
MS: 5x (500 at slower than T-pace, 100 drill, 50 non-free)
CD: 100 ez non-free