Hi,
I've started to make a workflow for swimming analysis with the steps below. I would be interested in any comments or feedback to improve or use other tools in Kinovea. It feels like there are easier/better ways to make these measurements that I haven't thought of yet.....
1. I can always see the start strobe light when the swimmers are on the blocks so I can use that as a good time reference.
2. I can now find a reaction time easily.
3. For the first few seconds I normally have a fixed camera perspective so I use the lane rope markers and lane widths to create an initial co-ordinate system.
4. From that I can estimate the length of the dive and the distance of the underwater phase and times for each of those.
5. Through the race distance we have to track the swimmer by moving the camera which changes perspective and breaks the co-ordinate system (I think it does anyway??). So to continue to find the distance and time data I use lane rope markers to project a line across the pool to find the time when the swimmer reaches 15, 25, 35, 45 and 50m.
6. I create a polynomial fit line in Excel to fit the distance/time data from step 5
7. I then go back through the video again and mark the each arm beats, now I have time points for each stroke and can calculate the stroke and cycle rate.
8. Using the equation from step 6 and time from step 7 I calculate an estimate of the distance along the pool at each stroke cycle. Now I have the data to calculate distance per stroke (DPS)
9. I can calculate the velocity for delta sections of the distance so with that and the DPS I can calculate stroke index (SI)
Cheers Mike