[Scott Johnston]

Alex:

Unfortunately, 3 weeks is not enough time to make significant changes in your aerobic capacity. I recommend using 132 for the top of Z2 and training as much volume as you can manage in the 120-132 range in the next few weeks.  Do this on a steep treadmill or stair machine if you do not have access to really hilly terrain. Cut your Crossfit to 1x/week and use that time for more aerobic volume.

Scott