Historical martial arts can be hard on the knees. But in my experience, 99% of the time the ‘crazy' positions we see in the sources (like the extract from Meyer, above), are perfectly attainable with a little, or a lot, of work, without significant risk of injury. It just takes patience, caution, and knowledge. I can't help you with patience or caution, but if you don't already have the knowledge, I can help. I have a free knee maintenance course designed to teach you the very basics of how to look after yourself while working on the mechanics of whatever historical swordsmanship style you practice.
A few months ago I got an email from Tony, one of my online students. He wrote:
I know you're extremely busy so you don't have to read the whole thing but I just wanted to say THANK YOU at the very least.
I have been interested in HEMA and learning long sword for years but never found a club or school nearby to help me learn. I have some martial arts experience, having a black belt in Tang Soo Do Moo Duk Kwan, and when I started looking into online videos and classes in my area, I paid close attention to the fundamentals like I'd been taught- footwork and stances (guards). I was pretty shocked to find that everyone in my area studies German long sword and the instructors pretty much have everyone picking up a sword and throwing zwerchaus in the beginner classes.
Then I saw Fiore practitioners, including yourself, online. Besides a solid grounding in fundamentals, the movements seemed very graceful. I did ballroom dancing for several years (it's how I met my wife), so I knew that I could make my body move like that. There was just one problem. I needed conditioning and I knew from personal experience that running was the easiest way for me to lose weight. Unfortunately, I had injured both of my knees when I was younger doing Tang Soo Do (a hyperextended kick), marching band (I did a spin turn on one foot but my heel got stuck in the turf), and the general punishment associated with running. I haven't been exercising in years and gained about 80 pounds as a result.
Fortunately, I discovered your free Knee Maintenance course, which has enabled me to resume my regular running routine. After going through the course, I realized that my knees were no longer moving correctly and, as you said in the video, the culprit was my hips. While I used to be able to do the splits, I had lost considerable flexibility in my hips, which was affecting my whole structure. I've also added the 7 way hips to my routine in addition to the knee massage. So far, I've dropped 35 pounds in the past three months, and I'm running 3 miles a day with no knee pain or injuries.
You can imagine how pleased I was to hear it. The main reason I teach swordsmanship for a living (as opposed to just training for fun) is the way it can transform lives. Over the weekend, Tony got back to me with a question, and added the following:
Finally, I’m still running every day to keep in shape for longsword training. No more knee pain. Lost 46+ lbs and counting. That knee maintenance course is amazing!
This makes me very, very, happy.
Of course as a good scientist (or trying to be), I have to add that just because it works for Tony doesn't mean it will work for you. And I'm not a medical doctor. But the course users are all invited to complete a short survey. Here are the results:
So the chances are good that it will help you. The course is completely free, and you can find it here. If you haven't tried it yet, perhaps you should!