My elbow, or more accurately the area just on the forearm outward side of the elbow, has been sore lately. If I pick something up it twinges, or if I hold the arm straight and make a fist it hurts.
It has been painful, but not debilitating- like a lot of things that happen with my joints since I turned thirty, I more or less just have been living with it. After some poking around on the internet, I found some references to tennis elbow  and concluded that this was the most likely culprit. I decided to give it a couple of weeks and, if treating it like tennis elbow with cold packs and compression improved it, to assume I was on the right track.
Basically, tennis elbow or “lateral epicondylitis” as it is correctly known is a repetitive stress injury. Of course I don’t play tennis, and in fact don’t do much of anything that involves repetitive use of my elbow, at least not that I could think of. But as I went to wash my coffee travel mug the other day, I painfully discovered one thing that I do that, in retrospect, almost certainly is the root of the pain.
The cause of my elbow pain is… washing my travel mug. To wash my mug, I fill it with water and cleanser, then shake it by swinging my arm at the elbow with an abrupt “stop” at the end of the swing, intended to break loose any “gunk” in the cap part of the mug. Picture two pieces of wood with a joint attaching them in the middle (my arm). Now put a one pound weight at one end (the travel mug filled with water), and imagine “snapping” that apparatus a hundred or so times. This would put a ton of strain on the joint and, in the case of a real arm, the tendons that hold the joint together. Thus my elbow tendon pain.
Once I started thinking down this path I recalled one other thing I did with my elbow involving a similar motion. I have a watch that has one of those “perpetual” winding mechanisms (in this case it is electric and it is a charging mechanism, but the idea is the same). Each time your arm swings, a weighted disk spins several hundred times and charges the watch. Well, I let it go dead a couple of times in the last month, and guess how I quickly recharged it? Yep, that’s right: by holding the watch in my hand and “snap swinging” my arm to spin the disk as fast as I could.
Mystery solved, and two more things for me to avoid in the future at the risk of causing myself mysterious aches and pains…