If there is honour among thieves, a far nobler entity should bond gladiators. In many sports, there is a code that the competitors respect. One general rule that crosses all genres of sport is to respect the knees.
In football there are rules against this: chop blocking and clipping. In hockey, the same principle applies and intentional checks against people’s knees are also called clipping. In soccer, players become irate when their knees are targeted in tackles. When these fouls occur, invariably tempers flare and a ruckus ensues.
The offended parties are justified in being upset, as this not only violates rules and a code of respect among athletes, but also jeopardizes their livelihood and permanent health. Knee injuries can end a career and cripple a person; a fact to which Cam Neely and various others can attest.
Recently, there has been a trend in MMA for fighters to throw leg attacks aimed directly at their opponents' knees. This happens from the standing position and from the seated open guard position to standing opponents. The goal is to hit the front of the knee and push it directly back. It would appear that this serves the purpose of causing long term knee injuries. A short term goal might be better served by attacking the thighs so as to tire and weaken their adversary while not causing permanent damage.
It is often described as a push kick/linear knee strike—or, to paraphrase James Toney, a "side-check kick". Most noticeably, Jon Jones and Anderson Silva are employing this dangerous tactic. These two are on everyone's pound-for-pound top five list. There is no reason as to why they would need to put their colleagues at such risk when they have so many legitimate weapons to utilize. Not only that, but the power that these two very highly skilled strikers can generate makes the possibility of seriously damaging a knee very probable. To be fair to both of these legends, they have never hurt an opponent with it and often seem to be aiming for the lower thigh above the knee which would not hyper-extend the knee backwards.
Naturally, people will argue that the move is legal and therefore any fighter is completely justified in kicking directly at the knee in an attempt to force it back most unnaturally. Some may also argue that it is a valid martial arts kick as practiced for generations. I would retort that adhering to a high standard of sportsmanship is a more noble trait than acquiring "W"'s. Further to that point, I would also pose the perspective that this technique is unworthy of representing the essence of competition and martial arts tradition.
For those that feel that this is a fight and people willingly accept the inherent risks, I would respond by stating that it is a sport. The fighters are humans. They are athletes today but they will not always be so. There will be a time in their lives when being able to walk is more important than being successful in athletics.
Admittedly, many fans would disagree and feel cheated by a ban on these attacks. I liken this to soccer-style head kicks to a grounded opponent. Banning that kick was most pragmatic and has saved numerous skulls from severe concussions. It also was not a popular decision at the time, and yet the sport managed to survive and continue to prosper.
I would ask supporters of this technique, just how aesthetically pleasing is it to view someone trying to smash in a knee? The soccer-style kicks were dramatic and intense. I would say that these push kicks are not. Why would someone want to see a fighter's career ended by having their knee caved in like this rugby player? One question that would test if this is within the code would be to query how would my training partners feel if I did this to them during practice. It is fair to say that that athlete would find great difficulty in finding sparring partners.
Some fighters, like Jacob Volkmann, state that the strike causes no serious injury and that it only serves to irritate the opponent. He believes that the only risk to a straight knee would be to the spraining posterior capsule or straining poplateal muscle. Frank Trigg, who carries an expert opinion as a pioneer, believes it is not dangerous nor dirty. Nate Quarry believes that there is a fine line between it being acceptable and not. Hopefully, no one will ever get hurt to prove Jacob and Frank wrong.
Rampage, while on The MMA Hour, voiced this opinion on the Jon Jones- Vitor Belfor bout at UFC 152 where Jones used this attack to the knee.
Vitor took the fight on short notice, and this is how you respect him, by kicking his knee backwards and stuff like that? He’s supposed to be a man of God. You can injure somebody, you can sever their career. You can mess people up for life kicking their knee back like that and he does it repeatedly, over and over. To me that has no honor. I take a lot of honor in fighting. He has no honor.
In summary, I would suggest that all athletic commissions consider researching whether or not the potential danger in these kicks would make banning leg strikes directed towards the front of the knee with the intent to drive the knee backwards a necessary action. Moreover, I would ask athletes that use this strike to reconsider. Kicks to the thigh serve one's aim in winning that contest much better as it tires the leg and limits the movement of the opponent while causing little risk of permanent damage.
The reality is that this not a Kumite, it is a legitimate mainstream sporting event. The fighters give enough as it is. They should not needlessly be asked to risk their future mobility as well. There is no evil Sensei Kreese demanding Cobra Kai exhibit no mercy. Let’s return to old school martial arts and show our competitors the ultimate respect by besting them with skill and not dirty cheap shots.