VO2 on the Bike: Definition and Use
This issue comes up every OS. I notice it has already appeared in the Week 1 Bike Thread; I thought of just commenting there, but I think this will generate a bit of discussion, and it deserves its own focus.
First off, the Nov OS people had a good conversation about VO2, how to measure, what it means, and how to use it in the context of OS workouts. That appears here:
http://members.endurancenation.us/Forums/tabid/57/aft/10177/Default.aspx ["30/30's" is a reference to one type of VO2 workout]
If you read that thread, the first posts there are mine, in which I give my thoughts on what the 5 min part of the bike test means, and how to think about using that number (if at all) when doing Thursday OS workouts. For those who don't want to slog thru the other thread ...
IMO, the 5 min "VO2" part of the bike test is there in order, as Ray Brown said, to fatigue you properly so the 20 minute portion (discounted by 5%) will be a better reflection of your FTP, which is properly defined as the power you can sustain for an hour - and who wants to do that!?
As Gordon notes, the Coaches' notes in the test indicate this number will be used for VO2 training during the OS. But when you look at those OS workouts, they simply say to do intervals @ "Vo2/Zone5/Very Hard". And the Calculator lists Zone 5 for bike as 110-120% of your FTP, as calculated from the test you are doing this week. So a little ambiguous.
My take is: if your 5 min "test" is less than about 116-118% of your FTP, then use the 110-120% figure for the VO2 intervals in the OS. If it is higher than, say 122-124%, you can probably use the 5 minute "test" number. But as always, the key thing is to use a target which allows you to (a) complete the whole workout and (b) come back ready for the next workouts without undue fatigue - week after week.
Also, the general theory is, if your VO2 is more than about 122-124% of your FTP, then you are stronger at shorter intervals than longer, and you are best served (in terms of long course triathlon racing) by focusing on getting that FTP up as much as possible, and not worry about what your VO2 is. OTOH, if it's less than 116%, raising your VO2 may be of as much or more benefit during the OS.
Everyone has an different "power curve", meaning for reasons of training, body type, gender, age, etc, they will be stronger at shorter or longer intervals. Pure Cyclists are fascinated by this, and use it to sort themselves into the type of racer they are, and what they should focus on in their training. Triathletes need to remember what they are training for, which in the end is the ability to go as fast as possible during the bike leg while conserving as much as possible for the run. Given that we are trying to ride as steady as possible, and the bike leg is a 2.5-6+ hour event, a high VO2 compared to FTP is actually of little value during a race. But raising your VO2 in concert with your FTP during the OS will be of great benefit when it comes to race specific prep
Anyway, this is just my take; I hope others will jump in, with both comments and questions.