In ground game, can a white belt BJJ guy gets an arm bar on a black belt BJJ guy?
I have never seen any of my new students takes down any of my old students. Not sure this applies to BJJ or not.
As in all arts skill (ie belt level) works to counteract other factors like size, athleticism & age - otherwise all combat sport competitions would be dominated by the old guys & there would be no need for weight categories
This would appear to be true for striking arts, standing grappling arts, ground fighting, MMA etc etc
However, in BJJ there is an initial steep learning curve so a much larger, stronger, younger white belt has pretty much zero chance against a tiny old black belt. That changes once someone has a few years of experience (eg blue belt) and physical factors come into play
There's a saying in BJJ that each belt level counteracts 10 years of age or 10lb (5kg). So a 30 year old blue belt would be a fair match against a 40 year old purple belt or a 80 kg purple belt would be a fair match vs a 75 kg brown belt
I agree with this principle, but in my experience the numbers don't quite work. I and my fellow 50 something black belts regularly spar with much younger, stronger coloured belts with no problems
BJJ is much more forgiving than striking or standing grappling in that if you mess up once you have a lot of options to recover the situation. In striking or standing grappling if you mess up once then you may be hit or thrown and it's all over
This is a little tangental to my advice to
@skribs about choosing his training partners. When you're rolling you should be focused on learning not winning. That involves trying new things and working on weaknesses and that requires training partners who won't injure you when you're doing that