The best diagnosis I have had for my knee yet is a grade one MCL sprain. I have really only approached one person for a diagnosis. It started hurting slightly a week and a half ago after my 20 miles and four hours of skiing day. I of course ran on it until a 17.6 mile run on very slippery roads made it worse. Who would have guessed?
I feel like an idiot most of the time when I get injured. I mean, signs clearly point to something in my body not working right, and I push it to the end of the workout, maybe even multiple days. I know, I know! That an ounce of prevention is better than the pound of cure that will have to be applied later, yet I struggle to take that first step and admit it is more than just a bruise. Soreness and discomfort are part of the sport. I have a friend who just had hip surgery on his labrum in his hip. Apparently it was like that for 10-20 years. A fantastic runner, reduced to not even going to his desk job, and using crutches for a problem that might have been diagnosed 10 years ago. We work to deal with the pain. We aim to ignore the senses in our body that say "stop!"
I am quite confident I will be fine in a month when I set off for Everest, but it's not the setback I wanted at this point. I had plans of some long, big back to back 6+ hour workout days of running and hiking. Maybe they will still happen, but putting in 30-40 miles two days in a row sounds a little hard right now when a two mile run is painful and even walking a mile involves some pain.
In a perfect world, of soft trails and dry pavement, running would not stress the side of your knee. When a person runs, of the maybe 200 Newtons per step, or 200 to 300 Newtons (an even better article) that go into horizontal forces, from my experience maybe 1-10 Newtons when running in a strait line are lateral forces. In other words, between 0.5% and 5% of the force that your left foot puts into horizontal motion probably pushes your body to the right. However, at 180-190 steps per minute it is only about 0.30 seconds before your right foot pushes back the other direction. The better the runner and more efficient and more experienced generally the lower the percentage of horizontal force is put into lateral motion. However, vertical forces are 5-10 times higher than horizontal forces (5 times at faster speeds and 10 times as slower speeds). Thus, if my left foot ends up just 2 centimeters farther to the left as I push off due to sliding on snow and ice that 1 or 2 Newtons of horizontal energy going into my left leg gets a portion of the 2,000 Newtons of formerly horizontal force that amounts to roughly 40 Newtons. Alone, 40 Newtons won't break my MCL. However, put in half a dozen skiing falls the week before, some asymmetrical running around an indoor track, and a 17.6 mile run on very snowy and icy conditions, and I have significant pain.
Let's say that I encountered that extra 40 N on a meager 10% of the steps I took. At 180 steps per minute and a 132 minute run that's 1188 sliding steps with my left foot adding a whopping 47,520 N into my MCL, which it would not normally encounter. How much is 47,520 N? That is about 10,682 lbs. or close to 10 lbs. more per step into a ligament that was not meant to take that kind of damage.
Our bodies are not invincible, but we can tolerate a lot of damage. I probably put roughly five tons of added stress into a little fiber in my body and I still ran four miles the next day.
I'm a believer in fate and purpose, even though that purpose often makes utterly no sense to us whatsoever! This happening to me now, it's a lesson I need to learn about strengthening myself laterally. It's a lesson about listening to my body when it is saying something is wrong. Why I have to learn (or rather relearn) this lesson so close to one of the greatest physical challenges of my life is beyond me. I am humbled again.