The measure of fitness I use for my own training, because measuring it is built into the exercise bike, is Functional Threshold Power, or FTP. It is defined as the maximum power output that you can sustain for 1 hour, measured in watts. The obvious way of measuring this is to get on the bike for an hour, but there are shorter ways of estimating it, e.g. do 20 minutes as hard as you can, and the bike will derate your average output by some fixed amount.
Any comments on the usefulness of this compared with VO2max? VO2max measures the very hardest effort you can reach, even momentarily, while FTP measures the hardest you can sustain indefinitely.
Not OP but I think Functional Threshold Power is fine. I don’t know of any literature directly comparing it to VO2max, but much of the literature on VO2max didn’t actually measure VO2max, it used proxies like “maximum gradient at which a participant can walk for 3 minutes” (called the Balke treadmill test. When meta-analyses report that VO2max strongly predicts health outcomes, what they usually* mean is “VO2max, and also various proxies for VO2max, when thrown together into a meta-analysis, strongly predict health outcomes”. So as far as I can tell from what (little) research I’ve looked at, there are a lot of metrics that work and it’s not clear which ones work better than others. And FTP seems like as good a measure as any.
The measure of fitness I use for my own training, because measuring it is built into the exercise bike, is Functional Threshold Power, or FTP. It is defined as the maximum power output that you can sustain for 1 hour, measured in watts. The obvious way of measuring this is to get on the bike for an hour, but there are shorter ways of estimating it, e.g. do 20 minutes as hard as you can, and the bike will derate your average output by some fixed amount.
Any comments on the usefulness of this compared with VO2max? VO2max measures the very hardest effort you can reach, even momentarily, while FTP measures the hardest you can sustain indefinitely.
Not OP but I think Functional Threshold Power is fine. I don’t know of any literature directly comparing it to VO2max, but much of the literature on VO2max didn’t actually measure VO2max, it used proxies like “maximum gradient at which a participant can walk for 3 minutes” (called the Balke treadmill test. When meta-analyses report that VO2max strongly predicts health outcomes, what they usually* mean is “VO2max, and also various proxies for VO2max, when thrown together into a meta-analysis, strongly predict health outcomes”. So as far as I can tell from what (little) research I’ve looked at, there are a lot of metrics that work and it’s not clear which ones work better than others. And FTP seems like as good a measure as any.
For example, have a look at Table 2 in Impact of Cardiorespiratory Fitness on All-Cause and Disease-Specific Mortality: Advances Since 2009, which gives a list of studies and what measure each study used. You can see that they used a variety of fitness metrics.
*I’ve only actually looked at two meta-analyses