Anecdoctal evidence and the Problem of inferring Cause

I'm finally back running after taking a nearly 5 week hiatus due to a self-diagnosed metatarsal stress fracture. The fracture came on quite suddenly during a run at Twin Brook. I completed the run, hoping it would go away. It didn't and I took a break, which was easy enough since all my major fall races were over.

I'm quite confident that the cause of the stress fracture was racing the 5K XC race 6 days after my first marathon and then the PT8k a week after that. The body is very good at adapting to stresses and the stress that I was giving my body all summer and fall was running at a steady, marathon (6:40-6:50) pace. Other than the few fun "sprints" (really about 400-800 meters) at Twin Brook, I hadn't run faster than 6:30 for three months, and faster than about 6:05 since Spring. My average pace at the 5K XC race was about 6:15 and the flat and especially downhill sections were significantly faster. My average pace at the 8K was 5:58. My feet weren't adapted for this pounding and the result was the stress fracture.

Wait, scratch that paragraph and read this instead:

I'm quite confident that the cause of the stress fracture was due to low bone density because of Vitamin D deficiency, as I've unintentionally cut back on the amount of milk that I drink at dinner (replaced largely with wine). Vitamin D deficiency is very, very common and Vitamin D fortified milk is a great source. Vitamin D increases Calcium absorption in the gut. With lower gut absorption, my low blood Calcium levels triggered Parathyroid hormone release, which activates the cells (osteoclasts) that remove the bony matrix from bones, releasing calcium to the other tissues.

Wait, scratch that and read this instead:

I'm quite confident that the cause of the stress fracture was due to running a road marathon two weeks before the bone finally fractured. I run mostly trails. Indeed, in training for the marathon I only ran two long runs (one 16 miler one 18 miler) on the roads. All my other long runs were on trail. I did run a weekly 10 mile marathon-pace run on the roads. But that was it. Our body is very good at adapting to the stresses we give it and I made the mistake of running a road marathon without training enough on the roads. While I made it through the marathon without incident, I clearly stressed my metatarsals enough that all it took was a little more running to give me the stress fracture.

Wait, scratch that and read this instead.

I'm quite confident that the cause of the stress fracture was due to changing my form only three weeks before running my first marathon. I was watching good running video and reading some literature on efficient running kinematics and decided that I didn't let my trailing leg extend enough before toe off (actually it's extension at the hip). I worked on this new form both before and during the marathon and two post-marathon races. The more more extended hip places additional stresses on the more dorsiflexed foot. Our body is very good at adapting to the stresses we give it and I made the mistake of racing the marathon and two post-marathon races using my new form without giving my body enough time to adapt.

Wait, scratch that and read this instead.

I'm quite confident that the cause of the stress fracture was due to trying out a new, minimalist shoe that I had received for review. I typically run in racing flats of various sorts, such as the NB 790 and 100 on the trail and the Asics Piranha and Hyperspeed on the road. Prior to this year, I also typically did 1-2 barefoot cooldowns per week but because of a bruised left forefoot (from landing on a rock while running downhill) I had not done any barefoot runs at all this summer or fall. The new minimalist shoes have zero cushion - they are simply a vibram sole with some cloth that wraps that foot. After receiving the shoes, I immediately went out and did some 5-8 mile runs. Our body is very good at adapting to the stresses we give it but I made the mistake of running in the cushionless, minimalist shoes without properly building up to the novel stresses that these placed on my foot.

Wait, scratch that and read this instead

I'm quite confident that the cause of the stress fracture was running with tight calf muscles following my first marathon. This calf tightness was new to me, so I was surprised to have it persist for over two weeks - up until the day that I stopped running in fact. I have no idea what the connection between tight calves and metatarsal stress fracture is, but I've repeatedly read that tight calves is a risk for metatarsal stress fracture on the web.

OK, ok. What is the point of all of this? Quite simple - all of these explanations make plausible stories. And importantly, that's what humans do, we create stories to explain events. The actual cause of my stress fracture may be one of these that I've listed, or some combination, or none. I simply don't know. Running injuries have complex causes and there are always numerous, plausibly causal antecedents. Why do people tend to assign cause to a single antecedent? I would argue it's the antecedent most consistent with the person's world view. So we often hear: "this hip muscle imbalance gave me this knee injury" or "this drink made me recover faster" or "this workout made me run faster." Quite remarkably, world view often trumps plausibility.

I don't really care that individuals make up stories to explain events in their life. We all do this. It's part of being human. The problem is when these anecdotal stories determine how professionals in the health sciences - broadly and liberally defined - practice health care.