In the dark my balance was suddenly gone.
A good ten years ago we did a training session without light. Balancing on a beam, a few other drills, all in pitch darkness. That's when I noticed I was suddenly behind everyone, even though with my eyes open I had one of the best balances in the group. The others made it across the beam, I kept having to step off. That stuck with me: why is my balance so good with light and so bad without? Today I know, because I can measure it. Wobble measures four conditions: firm and soft ground, each with eyes open and with eyes closed. Soft mat and eyes closed switches off two of the three senses that control balance and tests the inner ear, the balance organ, on its own. In the other three conditions I'm above the average for my age, in this one well below. So in my case the eyes and body sense do most of the work, the inner ear contributes little. With eyes open that never shows.

