Have you said the above?
Be honest. No one's watching you read this. Answer this question silently if you must.....
-That time the wrestler came in and held you down on your back with his head on your chest for 5 minutes.
-That time the Judo player came in and played only the top position, barely engaging your half-guard then cartwheel passing to north-south and pinned you.
-That time the strong blue/purple (gasp! even white perhaps....) belt came in fresh at the end of class, slipped on his Gi and you were rolling for the 2nd time that day.
If you're like me, you've said the above at some point in time...or some variation of it.
This is whiner talk.
It is an excuse.
A fight is physical. A tournament is physical. Jiu-Jitsu is a combative sport.
Blaming your loss, submission, being dominated by position on the physical is an attempt to negate the reality that your Jiu-Jitsu was compromised by something other than the textbook answer or technique.
One of the things one of my coaches said that still rings true to me is the following:
"There are 2 things in particular that win tournaments that I have NEVER had a black belt teach in detail or seen taught at a seminar: 1) spazz and 2) stall. You absolutely have to do these things to compete at a high level and win (hell, watch the white and blue belt divisions as your next local tournament. At some point you will stall with a minute left and or spazz-scramble to avoid a back take et cetera.
My point? The other guy may rely on conditioning, muscle, size, and/or athleticism. That is not an excuse for the failure of your application of Jiu-Jitsu. If all it takes is for someone to move a bit faster, be a bit stronger, or grind with constant movement for 5 minutes and stifle your game... you have holes in your Jiu-Jitsu which must be addressed.
If you only have expert or solid technique for 5 minutes there is a hole in your game. If you can be dominated by someone your size or close to it of the same rank simply b/c they are stronger/more athletic, you must learn to address this deficiency. Excuses will not win matches nor fights nor divisions in tournaments. Excuses will not prevent the bitter taste of being dominated by someone with "less(er) technique.
You should be glad there are guys that come after you like every class is the Mundials.
I've been armbarred viciously in tournaments due to laziness on my part and forgetting that some guys come after that arm like it's holding the key to unlimited vag or never having to work again.
We forget that with all the camaraderie and such, this is a combat sport. We are here to win, to dominate, to choke, to make limbs go against their anatomical design. The art of the finish is to render unconscious or maim.
No go pick up a kettlebell or do some bench presses. Do a grappler's circuit with some free weights.