Protective equipment vs. Concussions in Sword Fighting – HEMA / Buhurt / Reenactment / SCA

00:40 - First, lets briefly talk about concussions. They are mainly caused by head acceleration or deceleration leading to the brain getting compressed by the skull. So while the head is already moving, the brain - surrounded by fluid - does not change it’s velocity as fast due to inertia – leading it to “bump” into your skull. Other forms of “unfavourable energy absorbtion” include temporal deformation of the skull – leading to the same thing. Imagine a shockwave traveling through your head, tearing on your brain.

Sounds nice, doesn’t it?  Symptoms of a concussion are often non-specific. If you experience head-ache, cognitive slowing, emotional liability, amnesia, loss of consciousness, nausea, vomiting and / or sleep disturbances after a shock to the head stop the activity and seek medical attention. The under-reporting of concussions by athletes due to fear of losing time from participation in a tournament for example is an area of great medical concern. There is still a lot of research to be done about the long term effects of concussions, but they are associated with changes in mood, behavior, cognition, academic and work function, long-term morbidity, suicide rates, as well as activities of daily living.

02:13 - So remember, you are responsible for yourself and the health of your fighting partners. Check your training and fighting behavior. Specific neck training, proper gear, and medical treatment – all these measures are like a safety net. It’s great to have one, but better don’t fall of the rope in the first place – especially if you don’t know how well it will hold up.

02:40 - Unfortunately there are no empirical studies on concussions and protective equipment specifically for sword fighting. Who would have thought, right? But there are still some clues we can take from research on headgear in Hockey, American football, rugby and even bicycling. A meta-analysis of 15 studies concluded that while headgear significantly reduces the relative risk of superficial head injuries, it is suboptimal in terms of concussion prevention - as the difference in concussion incidence between the groups wearing headgear and those who did not was ambiguous.

03:24 - There are a few things that make this topic more complicated. First: It’s possible that the protective equipment changes the behavior of the wearer. This is called risk compensation: a strategy involving increasingly reckless play by those wearing protective equipment. This would diminish any difference between the two examined groups. Additionally research like this can’t be produced within a lab – after all you cannot just randomly recruit a few volunteers, put a helmet on their head… or not… and crash them into a wall.

So there might be also selective effects, where individuals who are risk avers in the first place are more likely wear protective gear, exaggerating the gear’s effect. We also have to differentiate the kind of shock, as it makes a difference if you get hit by a body or by the earth – i. e. falling.

04:31 - Oversimplified we can think about it as a problem of minimizing the kinetic energy our head needs to absorb.

04:41 - As kinetic energy is mass times velocity squared, you can already see that moving at half speed at the point of impact (stopping your blow) will cut the kinetic energy of any strike by 75%. Reducing mass by using a lighter sword or by not driving your thrusts and cuts with your body into the opponent can also have a huge impact. The balance of your sword as an impact here as well and I won’t tell you anything new that a top-heavy sword strikes harder blows.

Just keep in mind that it makes a difference how tightly you grip your sword at the moment of impact for example.

05:22 - There are a lot of possibilities of how energy actually can be transferred. I try to keep it simple. First, if a blow is simply deflected by the helmet, then very little energy is actually transferred into the head. Velocity is a vector or simply put: Speed with a direction. If these two things change less, then less energy was needed for that change.

05:50 - Helmets and weapons therefore should encourage deflection by design. A rubber safety tip, while preventing penetration, can thus increase the transferred energy to the head if the sword now sticks to the helmet instead of sliding off. The same thing can hold for soft helmet overlays to a degree, which is also one reason why soft headgear in other martial arts like boxing is widely abandoned. Then again, these overlays have other positive effects that make this analysis so difficult.

For know, you can keep in mind to use materials that are at least not sticky to present a smooth, hard surface.

06:35 - Lets talk about little energy storages, as I like to think about them. Padding, suspensions and bending swords absorb a part of the energy a strike or thrust transfers to release it at a later point of time. You can think of all three as a spring that gets pushed together to release its potential energy later. This can delay the energy transfer process from blade to head, leading to a slower acceleration, but it depends hugely on the energy of the impact.

So if a rugby player strikes the ground head first for example, there is only so much padding can do. Luckily, tackling head first into an immovable object isn’t something I do in HEMA, but if a blade is too stiff you will definitely feel it in the thrust. Another debate that is going is if padding or a suspension system is better. From a scientific perspective, they both fulfill the exact same role. Both can be good or bad depending on the quality.

In HEMA at least, I would say that most fencing masks are not adequately padded on the inside as they were originally designed for much lighter impacts. A very easy solution might be to just get a bigger size and use your own additional padding or maybe even a scrumcap.

08:11 - This might not desirable if you want to use your headgear for a long time, but if the helmet deforms slightly, then that’s energy not going into your head. If an overlay in HEMA goes flying off, that’s a good thing. If the helmet slips slightly, causes friction between the padding and your head, you feel the warmth of the portion of energy that didn’t move your head. Of course, in an ongoing fight this might be suboptimal for a lot of other reasons… After all, you should care about all possible injuries.

08:48 - Weight matters. No seriously, if the opposing strike has to move more mass with the same amount of input, the result will be less velocity and thus less acceleration. A heavier helmet, a strong neck or a system linking your helmet to your body have this effect. But be aware that a heavier helmet will also compress your spine. So, I’ll just repeat myself: Train your neck.

09:16 - And that’s it:  Use reasonable weapons and appropriate behavior, maximize deflection via non sticky surfaces, use good padding or a good suspension system (best on the inside of your reasonably weighted helmet) and train your neck. Leave a like and a comment under this video to help me grow this channel. I also happily take suggestions for future videos. So long, until next time, take care!.