It’s easy to get lost in all the fitness data you can collect now during your workouts. Does anyone really need to know their power output when running? So far, I’m convinced most of it is just noise. Maybe interesting noise, but not really all that helpful in helping you get more fit or get more competitive.
Of course it’s not all junk data. Some of the data is helpful to track. I like to use two particular fitness tests, one for cycling and one for running, and tracking the resulting data from those tests really helps me judge my current fitness, any improvements, and just what I can expect in any upcoming races.