That's my gut feeling also - that max HR is sort of genetically determined and doesn't get higher. (I will look into that more and ask the folks we work with at Endurance PTC and see what they say).

What you CAN raise with work, are your lactate thresholds. (For truly useful analysis, there are 2 lactate or ventilation thresholds: (1) VT1, the lactate threshold in which lactate begins to accumulate in the blood (which leads to a transition to steady state metabolism, the endurance training zone) and (2) VT2, the point at which steady state metabolism can no longer be maintained (the transition from heavy to extreme exercise).) You can also raise your power outputs (i.e. how much power are you putting out for a given HR).

It seems to me that V has raised her VT1 level with training. This is her moderate/endurance zone. My VT1 level was fairly close to this at the beginning of last year (156 - 173). Not sure what it is now (probably 120! ). Power outputs at these levels is key also. How much power can you put out at a given HR? I'm hoping mine improved from last year, but with this time off the bike I'll be lucky to stay at the same level.

so for Tuckervill's question, I think for sprints, you are going to be going above the VT2 level, close to max regardless. I have some questions about how this max type work fits into your overall training plan, though. How often are you doing these max type efforts? How much emphasis is on interval and endurance pace training?