About once a year, as new students come in, I have to give the sparring lecture. As a school owner, the amount of contact to allow when students spar is always a tricky subject.
For one thing, most insurance policies for martial arts schools don't allow much contact, and you have to make your policies clear or else you can be in big trouble if someone gets hurt.
But some other variables come into play when you're a student:
1. Students can't train if they're hurt. If you spar someone and you don't care how hard you kick or hit them, you can put them out of class with one stupid move. Too many people come in and swing for the fences. Even some black belts enjoy showing beginning students who's boss. Once, I saw a black belt crack a beginner's rib the very first time this new guy sparred. The new student dropped out of class very quickly. The black belt didn't really do it maliciously--he just wasn't thinking. I know a black belt who once dropped out of another school because he was "tired of being a punching bag" for the more experienced students. Any teacher that allows advanced students to hurt less experienced students is crazy, irresponsible, or just not paying attention to the needs of his students.
2. Higher-ranked, or more experienced students, have a responsibility to help lower-ranked or less experienced students. What good does it do a higher-ranked student to beat the heck out of a less experienced student? It only fuels the ego. It's often a testosterone thing. We want to be top dog. We want to show who can pee the highest on the tree. But a higher-ranked student who has his head together (and a little self-esteem) will help teach less experienced students. When sparring, you'll score your points, you can pressure your partner and give them a taste of the type of skill they're aspiring to attain, and then you'll allow your partner to score points, work on techniques, and acquire confidence. If all you want to do is show them who's better, nobody improves. You must be a coach; you must motivate and inspire, and you don't do that by mopping up the floor with someone.
3. Some students don't understand that REAL SKILL involves using power without contact. To throw a technique that comes real close and has power requires more skill than throwing a power technique that hurts someone. It involves practice and self-control, and that's something that's lacking in a lot of new students (or students with some emotional baggage).
When I give this lecture, I usually tell students that if they want to hurt someone, there are other schools that are into that. Pat Militech trains the best ultimate fighters in the world just about 5 blocks from my school. He's the best at what he does. When you go there, you almost expect to be hurt. It draws people who are looking for something different than what I teach. I think ultimate fighting is cool, and if I were 20 again I might be training with Pat, but that's not what I'm into at age 54.
At my school, students learn an art, and they also learn to fight. Some of my students have had to use what they've learned in real self-defense or police situations, and it works. You don't have to hurt someone in class, or be hurt, to be a great fighter.
In the end, it boils down to respect--for yourself and others. It also is a matter of inner strength. As the old Zen/Taoist saying goes--it takes force to master someone else, but it takes strength to master yourself. In my view, anyone can use force. A skilled martial artist exhibits strength of character and self-control.