Finishing a training session and immediately lying on the floor, and staying there long enough to have a photo taken for your social media accounts, is bullshit.
I have never allowed it in my gym, and I do not do it myself.
We train to perform.
Perform what? Well that is up to you.
But what if that performance is something that requires cognitive acuity, what if there's a need to be watching, looking, thinking? What if you need to be still thinking about strategy? What if you don't know how long you have until the next play?
Granted, my personal background is in martial arts ans security work. In security work, you may have an exhausting encounter in that you have to control and restrain a guy. How long is this going to go on for? Will there be a second incident? A third? Do you now have to give an incident report? You need to be mentally ready and able to recover fast enough to be physically ready.
If you're a martial artist, will there be an extra round?
If you're a rugby player, you must be ready for the next phase of play.
When you do your physical preparation, ie your gym training, you are not just picking up and putting down weights, you're not just huffing and puffing through your conditioning sets.
You are training. Preparing.
This preparation is as mental as it is physical. You train the mind, your thought process as much as you train your muscles.
So by all means take a knee at the end of a set, but keep the eyes up, open up that peripheral vision, get the exhales longer and slower, actively prep for the next round, EVEN IF THERE ISN'T ONE
Don't flop out on the floor.
The person laid out on the floor is the person who lost the fight. The winner is up and looking about.
Be the winner.