03-29-2017, 04:20 AM
ESPN finally showed a 2 hour portion of the NCAA Women's Swimming & Diving Championships.
Rowdy Gaines, in his commentary seconds after the 200 Free race, as he is seeing the replay for the first time: "Katie Ledecky. I thought she had it [the win] from this vantage point. I thought it was all hers." But the times came up the same: 1:40.36, which is considered a tie.
I've seen many instances where I felt that swimming touchpads do not accurately record finishes. I believe that the touchpad in Katie Ledecky's lane was slow to record her touch. The video of the camera directly above the finish seems to indicate that Katie touched the wall more than 0.01 seconds ahead. The apparent distance that Mallory is from the wall when Katie touches agrees with this.
In swimming, by definition, two swimmers who record the same time to the 0.01 second are declared to have tied.
Because of the discrete nature of the clock, two swimmers can be arbitrarily close in actual finish (say, 0.000001 seconds) and yet receive different times. Likewise, a swimmer whose arbitrarily precise finish is 0.010000... or more seconds faster than another swimmer should get a faster time by 0.01 or more seconds. A swimmer that finishes 0.01 - 0.000001 seconds behind may receive the same time. A swimmer that finished 0.005 seconds behind has a 50% chance of receiving a slower time and a 50% chance of receiving the same time. In theory.
At swimming speeds, what distance is covered in 0.01 seconds?
Swimming a 200 yard race in 1:40 is almost exactly 2 yards/second = 72 inches/second = 0.72 inches/ 0.01 seconds. The actual swimming speed is a little slower (starts & turns are faster than swimming), so let's just look at the last 2 lengths. The timer catches when her feet hit the wall with 50 yards to go, and the race ends with the touchpads register her hand touch. Katie Ledecky swam the last length (50 yards minus (her body length+arm length), so about 47.33 yards) in 25.62 seconds (Comerford swam it in 25.53). That averages out to be 66.5 inches per second, or 0.665 inches/0.01 seconds. One inch is about from the tip of your index finger to the middle of the first knuckle. In 0.0167 seconds, the swimmer travels 1.11 inches.
If you want to correlate the distance between the position of the fingertips versus the time between touching, you also have to consider if the arms are moving faster than the average for the swimmer. They certainly are moving faster at times during a stroke, but when you've stretched out to touch the wall, the fingertips will be traveling at the speed of the body.
So, between Katie Ledecky and Mallory Comerford, the two swimmers should be within 2/3 of an inch of each other for them to possibly correctly get the same time. If they're more than 1/3 of an inch apart, there is a more than 50% chance that they will get different times.
Attached are consecutive frames of a camera that looked almost perfectly straight down over the finish (you can see the front of the touchpad, so the actual touch is not hidden). Â
To calculate the frames (images) per second, I took a recorded basketball game, also broadcast by ESPN and counted the frames in one second as an on-screen clock counted down the tenths of a second at the end of a quarter. There were 60 distinct images in one second. When I watch the real time feed of the race (recorded on a TiVo), there are 8 frames (distinct images) from the splash of Katie's last arm entry to the splash of Mallory's last arm entry. When ESPN steps through the consecutive frames of the overhead view, there are also 8 frames. So, the overhead frames are effectively snapshots every 0.0167 seconds.
In frame 1, Katie is about to touch. Her fingers appear to be about 0.5-1 from the wall, but it is hard to be sure. [I dont really trust my estimated distances here. Use your own judgement.]
In frame 2, 0.0167 seconds later, Katie has clearly already touched. It appears that the 3 middle fingers have touched but the little finger and thumb have not yet touched. Jam your hand, fingers first, into a wall and see what happens. As the momentum of the body pushes the main part of the hand toward the wall, the hand will travel downward causing the fingers to bend, as though they are bending upward (but they really don't move upward - Sorry, Rowdy). Mallory's fingers appear to be 1.5-2 from the wall.
In frame 3, 0.0167 seconds after the image that shows Katie touched, Mallory has not yet touched as there is still blue between her hand and the wall. Her fingertips appear to be about 0.5 from the wall.
In frame 4, Mallory has finally touched. Note that in the four frames, Mallory's arm does not appreciably extend further. Therefore the estimate that her fingers are traveling at the same rate as her average swimming rate is reasonably accurate.
Because we can see that Katie has touched in frame 2 and that Mallory has not touched 0.0167 seconds later in frame 3, Katie's time to the hundredth of a second should have been at least 0.01 (likely 0.02) seconds faster than Mallory's. Assuming a sane design of the touchpad's timing, the only explanation I can come up with is that the touchpad did not register Katie's touch when it should have.
We see the main part of Katie's hand drive all the way to the wall. She didn't jerk her hand back. She didn't swipe at the wall. I am very confident that her fingertips exceeded the rated touch sensitivity of the touchpad.  In my opinion, the current touchpad technology does not accurately record swimmer's touches to the hundredth of a second.
In this case, in my opinion, the touchpad cost Katie the outright win. Rowdy, you were right in your first assessment of the outcome.
(The attached images are unfortunately not screen caps. They are photos of a TV screen, and then cropped & reduced in quality to meet the size requirements for attachments.)
[Edit: I initially thought the frames were 0.033 seconds apart but I realized they were 0.0167 seconds apart. This doesnt change the argument that the touch didnt register, and that Katies time should have been 0.01 or more faster than Mallorys, but it does halve the time difference (from >0.033 to >0.0167). It also made me realize I was slightly overestimating the distance to the wall.]
Rowdy Gaines, in his commentary seconds after the 200 Free race, as he is seeing the replay for the first time: "Katie Ledecky. I thought she had it [the win] from this vantage point. I thought it was all hers." But the times came up the same: 1:40.36, which is considered a tie.
I've seen many instances where I felt that swimming touchpads do not accurately record finishes. I believe that the touchpad in Katie Ledecky's lane was slow to record her touch. The video of the camera directly above the finish seems to indicate that Katie touched the wall more than 0.01 seconds ahead. The apparent distance that Mallory is from the wall when Katie touches agrees with this.
In swimming, by definition, two swimmers who record the same time to the 0.01 second are declared to have tied.
Because of the discrete nature of the clock, two swimmers can be arbitrarily close in actual finish (say, 0.000001 seconds) and yet receive different times. Likewise, a swimmer whose arbitrarily precise finish is 0.010000... or more seconds faster than another swimmer should get a faster time by 0.01 or more seconds. A swimmer that finishes 0.01 - 0.000001 seconds behind may receive the same time. A swimmer that finished 0.005 seconds behind has a 50% chance of receiving a slower time and a 50% chance of receiving the same time. In theory.
At swimming speeds, what distance is covered in 0.01 seconds?
Swimming a 200 yard race in 1:40 is almost exactly 2 yards/second = 72 inches/second = 0.72 inches/ 0.01 seconds. The actual swimming speed is a little slower (starts & turns are faster than swimming), so let's just look at the last 2 lengths. The timer catches when her feet hit the wall with 50 yards to go, and the race ends with the touchpads register her hand touch. Katie Ledecky swam the last length (50 yards minus (her body length+arm length), so about 47.33 yards) in 25.62 seconds (Comerford swam it in 25.53). That averages out to be 66.5 inches per second, or 0.665 inches/0.01 seconds. One inch is about from the tip of your index finger to the middle of the first knuckle. In 0.0167 seconds, the swimmer travels 1.11 inches.
If you want to correlate the distance between the position of the fingertips versus the time between touching, you also have to consider if the arms are moving faster than the average for the swimmer. They certainly are moving faster at times during a stroke, but when you've stretched out to touch the wall, the fingertips will be traveling at the speed of the body.
So, between Katie Ledecky and Mallory Comerford, the two swimmers should be within 2/3 of an inch of each other for them to possibly correctly get the same time. If they're more than 1/3 of an inch apart, there is a more than 50% chance that they will get different times.
Attached are consecutive frames of a camera that looked almost perfectly straight down over the finish (you can see the front of the touchpad, so the actual touch is not hidden). Â
To calculate the frames (images) per second, I took a recorded basketball game, also broadcast by ESPN and counted the frames in one second as an on-screen clock counted down the tenths of a second at the end of a quarter. There were 60 distinct images in one second. When I watch the real time feed of the race (recorded on a TiVo), there are 8 frames (distinct images) from the splash of Katie's last arm entry to the splash of Mallory's last arm entry. When ESPN steps through the consecutive frames of the overhead view, there are also 8 frames. So, the overhead frames are effectively snapshots every 0.0167 seconds.
In frame 1, Katie is about to touch. Her fingers appear to be about 0.5-1 from the wall, but it is hard to be sure. [I dont really trust my estimated distances here. Use your own judgement.]
In frame 2, 0.0167 seconds later, Katie has clearly already touched. It appears that the 3 middle fingers have touched but the little finger and thumb have not yet touched. Jam your hand, fingers first, into a wall and see what happens. As the momentum of the body pushes the main part of the hand toward the wall, the hand will travel downward causing the fingers to bend, as though they are bending upward (but they really don't move upward - Sorry, Rowdy). Mallory's fingers appear to be 1.5-2 from the wall.
In frame 3, 0.0167 seconds after the image that shows Katie touched, Mallory has not yet touched as there is still blue between her hand and the wall. Her fingertips appear to be about 0.5 from the wall.
In frame 4, Mallory has finally touched. Note that in the four frames, Mallory's arm does not appreciably extend further. Therefore the estimate that her fingers are traveling at the same rate as her average swimming rate is reasonably accurate.
Because we can see that Katie has touched in frame 2 and that Mallory has not touched 0.0167 seconds later in frame 3, Katie's time to the hundredth of a second should have been at least 0.01 (likely 0.02) seconds faster than Mallory's. Assuming a sane design of the touchpad's timing, the only explanation I can come up with is that the touchpad did not register Katie's touch when it should have.
We see the main part of Katie's hand drive all the way to the wall. She didn't jerk her hand back. She didn't swipe at the wall. I am very confident that her fingertips exceeded the rated touch sensitivity of the touchpad.  In my opinion, the current touchpad technology does not accurately record swimmer's touches to the hundredth of a second.
In this case, in my opinion, the touchpad cost Katie the outright win. Rowdy, you were right in your first assessment of the outcome.
(The attached images are unfortunately not screen caps. They are photos of a TV screen, and then cropped & reduced in quality to meet the size requirements for attachments.)
[Edit: I initially thought the frames were 0.033 seconds apart but I realized they were 0.0167 seconds apart. This doesnt change the argument that the touch didnt register, and that Katies time should have been 0.01 or more faster than Mallorys, but it does halve the time difference (from >0.033 to >0.0167). It also made me realize I was slightly overestimating the distance to the wall.]
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