Sparring is a puzzle. A puzzle that constantly evolves as you and your training partners evolve. Sparring in class is not about winning or losing, it's about trying to solve the puzzle, or at least figure out a piece of it. Or in some cases, you are the piece that needs to be solved. Sparring in competition is competitive with people of a similar age, size, gender, and experience.
If you look at most martial arts, brackets are broken into the above four categories. At least to some degree. For example, when I did wrestling in middle school, it was by age (we were all 6th-8th grade) and size (weight class). Experience and gender weren't a factor, but if there were more girls wrestling then we probably would have had a separate bracket.
In both Taekwondo and Brazilian Jiu-Jitsu, you sign up for tournaments based on belt, age, gender, and weight. (In TKD, weight is often only for higher-end competitions, and you just try to make brackets with similar size after the other three are considered). Age is something where Adult is the highest competitive bracket, and adult has a hard lower limit of 18 and soft upper limit of 30. A 15-year-old cannot compete as Adult. A 35-year-old can compete in the Seniors (TKD) or Masters (BJJ) division, or they can opt into the Adult bracket if they want higher competition.
There's even a rule of thumb in BJJ that when you go down in age by 10 years or up in weight by 20 pounds, that's the equivalent advantage of going up a belt in skill level. So a 25-year-old blue belt at 200 pounds should be roughly competitive with a 35-year-old brown belt at 180 pounds.
I recently completed my 4th degree test, and one item I had to complete prior to testing was an essay on how martial arts benefits everyone. In my section on seniors, my research showed the following as you get older:
- Slower response delay to stimulus, slower reaction times
- Slower metabolism, slower healing, increased recovery times
- Reduced athleticism and reduced flexibility
All of these things are disadvantages. However, the benefit that comes from training and experience is you are less reliant on youthful stats for success. It's the same as size. In BJJ, if you have two white belts who are 50 pounds apart, the smaller white belt is pretty much guaranteed to lose. But if you have two brown belts that are 50 pounds apart, the smaller brown belt will have the technique and experience to overcome it. As you get older, you have less athleticism, slower reactions, and less flexibility, but you can still make things work with proper timing and strategy. So can your opponent...but the young ones tend to rely on their speed over anything else.
My Dad has always said, "Old age and treachery beats youth and enthusiasm."