You become what you do.

If you are now training for longer-distance tris, your body will adapt to that.

Honestly, you do NOT want to keep all that muscle, it just slows you down.
(unless you are Ashley Horner, her body craves it. /end pink)

I went from a max weight (at 5'10") of 185 and maybe 12-13% BF, and being asked if I took steroids, to 154 or less and 5-6% at my fittest when training for IM's and HIM's.
And being asked if I'd been sick or wanted a sammich.

I can't bench press my way out of a wet paper bag anymore, but I'm a crapton faster running and biking at this body comp.

IF you really want to keep muscle mass & size and still do endurance-y sports, stick to sprint Tris and/or do Spartan races instead.

---

float , hammer , and jog

When I was younger I worked several summers on a mid size vegetable farm in the Central Valley of California.

The other workers were illegal aliens and took their jobs very seriously.
Because I was “new” on the farm and a gringo, I was assigned to the irrigation crew.

This job was the most unpopular one the farm.
It involved assembling and disasembling a series of irrigation pipes.
This meant one was constantly lifting and carrying heavy piles of pipes through knee deep mud in 105+ weather.

The people who did this job had the bodies of triathletes!!!!
That is correct!
The hardest, hottest, most strenuous physical labor I have encountered makes one look like a triathlete.

What job on the farm makes you look like a body builder then, you might ask?

Lot’s of the guys who worked in the packing shed, with the older women, lifted weights on the side. Some of them were quite muscular.

But the packing shed was easier and therefore paid less than field work.

Why do I tell this tale??

The question arises why “am I built this way?”

I think the answer should be- to get the job done..

But what is the job?

I think the job is to be good at stuff.
Good at triathlon. Good at rock climbing, cycling, mountaineering, working outside with your body in the elements.

I suppose lifting weights is a thing.
But it is an in door thing.
A thing that probably should be considered as part of another thing.
(I.e. too maintain strength so that I can .......)

We live in a society that is dominated by image.

“I lift weights to appear manly. Women like that.”

A better answer would be...
“I try to be very good at the stuff I do. I don’t care what others think. But some people prefer competence.