Topic: video timing vs manual chrono (timex stopwatch)
Hi! I am a swimming coach currently conducting my graduate studies (experimental research). I tried to verify video timing (kinovea software) compared to manual chronostopwatch then difference is at 2-3 seconds which is a very big variance when it comes to swimming.
Here's how i did: I had a 5meter marked (above and underwater) located at the center of the pool then when the swimmer head (wearing colored cap) crosses the 1st mark the timer (timex chronostopwatch) starts then stops when it hits the 2nd mark. I am using a sony action camera filming at 120fps. Based on my manual record it is at 7seconds then based on kinovea timing (kinovea stopwatch) same procedure it is at 4 seconds. Is there anyone who can help me out with this issue? since it would be much easier for me to gather data thru video than manual timing as to avoid the reaction time of the tester.