Ajax Bay wrote:
What athlete - let's leave participants (aligns with your "someone trying to finish an IM") out of this - sensibly uses daily weigh ins to
"confirm all sorts of fueling and hydration questions" - what questions? And addressing your last sentence: power and HR are useful for adhering to effort levels for training.
Does this look "silly":
"If you're swimming, cycling and running a lot / a decent amount you don't need to look at weight, it will take care of itself".
If you're coach (maybe you are) I'm sure you'd ask an athlete to share the sessions they actually executed.
Would you ask them to share daily (or even weekly) weight measurements? Really?
A sensible serious athlete will keep an eye on their weight, but "every day"? Not recommended.
I'm with @Sub17: "If you're eating healthy and active you don't need these [all these] data points. It will take care of itself . . . doesn't require an eating disorder with daily weigh ins to get you there."
One question is - are you refueling and rehydrating enough after hard sessions? Our training staff used to have us weigh in and weigh out before and after each practice during our training camps (soccer) to make sure we were replacing what we were sweating out and burning off during our sessions. So that's getting weighed four times a day. If we lost more than a certain % of our starting body weight we had to sit out. Just one example of how gathering ongoing weight data might be useful (and hopefully it's obvious here why only weighing once a week or once a month would not have helped us in this instance).
Weight is *one* thing an athlete may focus on. Certainly not everyone. For some (probably many at the elite level), their weight does work itself out without an extra effort beyond eating well. But if an athlete or their coach has identified weight as an area where they can improve, how could they possibly target that area in a serious way without taking regular weight measurements? We don't blink when athletes do aero testing (even though they're already pretty aero) to find gains, or do a big bike block to increase FTP (even though they're already crazy strong), or work with a swim coach to refine their technique (even though they're already a fish). They identify an area to improve, set a goal, make a plan to reach it, then gather data along the way to measure progress. The same can be done with weight *if* that's an area they have identified they want to work on.
But back to the original point of all this, no one should be shamed / abused into making any changes to themselves or their body.