I have seen this happen in the last few years, and I have seen this happen decades ago:
A martial arts gym is teaching martial arts, with the vast majority of students doing contact free sparring.
Some of the students get good enough to participate in combat sports.
The instructor starts putting focus on these good students, knowing that the reputation of the school is on the line.
The pressure comes off the other students to spar, because it is something that those advanced students do.
Next thing you know, class by class, sparring gets so deprioritized in favor of conditioning, drills, or some other "critical" type of training, that sparring disappears in the regular "classes" of the school.
New students think that a certain level of fitness is first achieved before sparring, leaving no one to spar with for the not-official-fighters.
The classes become first and foremost conditioning classes with little or no sparring, while the relatively few fighters at the gym are the only ones sparring.
I call this disease "fighercitis." It's sad. It destroys schools. It destroys entire great martial arts systems. I know of no cure. All I can do is warn to never allow non-sparring classes into your gym or school, because it will destroy you as a resource for average students to learn martial arts skills, and perpetuate backwards, destructive ideas about martial arts. You will burn in hell for teaching that Tae Bo bulls***:
There is, simply put, a right way and wrong way to kick, one virtuous "traditional" and the other nefarious "Superfoot." Traditional uses a whole-body-motion to generate power with the hips, while Superfoot prides itself in "only the foot moving." The Superfoot technique comes from that abomination that is stop-and-go kumite point fighting. The foremost advocate of this was Bill "Superfoot" Wallace:
Consider what this Superfoot technique did to the art of Tae Kwon Do. Before they started using Superfoot kicking, Tae Kwon Do produced fighters with real skill:
But now that Tae Kwon Do has come to rely on Superfoot technique, it has now turned into a pile of silly garbage:
It is interesting to note that Bill Wallace actually lost a testicle kicking that way, exactly as you would guess from watching the first above video. I am not saying Bill Wallace couldn't fight, I am saying that if he had not retired when he did he would have probably lost his other testicle, and I am also saying his Superfoot kicking style did not survive the scrutiny of the global martial arts community:
Notice how that mentions Benny "The Jet", and how he sought out competition in Japan after having fought a Muay Thai fighters. The traditional style of kicking was far older and and more ubiquitous throughout East Asia, and was prominent in China and Japan, not only Thailand:
This is more obvious when observing this type of lead leg kicking technique with the most traditional kick of all, the front kick. Notice how much more similar this is to kicks found in old Karate and Kung Fu forms than the strange antics of the Superfoot technique:
This is another example of why I say Muay Thai is the key to understanding most Traditional Martial Arts.
Here's my take on what type of martial arts training is appropriate for people at different ages...
For children, your best bet is some form of grappling, because should they lose their temper, be guilty of bullying, or have to use their skills on another child in self defense, at least they are wrestling around with the other child instead of physically beating the other child. Regardless of what the child goes on to study as they grow older, the grappling of their childhood will always be helpful to them. My first pick would be BJJ - it has all the bells and whistles kids like in martial arts, and the techniques they learn are immediately useful even to beginners:
My second choice would be wrestling, though this is usually a less pleasant experience for the child. If neither of those are available, Judo or Sambo is a viable 3rd option. I would avoid pseudo-grappling styles that don't include any actual sparring.
In childhood and early adolescence, cardio training in general is especially important, as it is the main exercise factor that contributes to healthy body growth at this age. BJJ is a very cardio intensive work out, and most BJJ coaches encourage their students to do cardio training (if not make them do additional cardio training in class.)
Once a youth is old enough to have a driver's license, and have friends who drive cars, they can potentially get into a wider variety of self defense situations. While grappling is the best way to handle an opponent one-on-one, striking training (like boxing or Muay Thai) includes skills not focused on heavily in grappling that are very handy if a strangers attack: managing distance, using footwork to avoid attacks, landing blows to the jaw or legs that can significantly slow down or stop an attacker. My first pick here would be Muay Thai:
Other types of traditional kick boxing with low kicks like Sanda, Savate or Knock-Down Karate (like Enshin or Kyokushin) would be my second choice, though they lack the extended clinch fighting of Muay Thai. Boxing would be third viable option if the other choices were not available. I would avoid any self defense style that didn't include any actual sparring, or which did stop-and-go "point fighting."
In late adolescence and young adulthood in addition to cardio, strength training is very important to promote good body growth. This builds a healthier foundation for the rest of their life. A good traditional kickboxing style with low kicks is itself a challenging strength training exercise, and all instructors have their students do strength training as part of their striking training, and many instructors also encourage their students to do additional strength training outside of class.
Adults interested in martial arts should peruse a well rounded martial arts education if they don't already have one. MMA would be my first choice here, because it will help you clear up any misconceptions you might have about your own ability to defend yourself:
If MMA isn't available, than any of the above mentioned martial arts would make a decent 2nd choice. Adults need to build flexibility in addition to cardio and strength training, in order to promote longevity and reduce injury. By this I am not talking about "warm up stretches" I mean going for serious gains in flexibility. Training to do both striking and grappling together as in MMA is a good flexibility exercise in and of itself, and most instructors have stretching exercises as part of their curriculum, as well as encourage students to pursue flexibility exercises outside of class.
There are many interesting esoteric martial arts out there like weapon martial arts, self-defense styles and Tai Chi. But in order to utilize those advanced techniques you need a foundation of solid basics that includes plenty of sparring first!
