Interesting. My conclusions were based on over 200 trials over several weeks using several dozen athletes. I wonder if your touchpad is defective? The touchpad should have less variability if the person is accustomed to using it. The 1.8m fly (or any distance for that matter) has inherent variability built-in because you’ll never enter the timed zone at exactly the same speed (unlike with the touchpad where we know the initial velocity = 0m/s). I was actually able to pinpoint the timing variability to the starting mechanism using a fly time. Some of it was due to the tolerances of the sensor but also due to slight trial-to-trial variability with the low body angles and wide sweep of the arm swing which could effect the time that the sensor is triggered.