FINA Relay Take-Off Rule w/ Automated Equip?

In the patent application for the Daktronics relay exchange platform (patent 7403135), in the background for the patent, it says In current practice, it is difficult for an electronic timing system to detect the actual instant the second swimmer loses all contact with the relay takeoff swimming platform. Currently available relay takeoff sensors rely on measuring the force exerted by the second swimmer on the relay takeoff swimming platform, some using a mechanical switch mechanism in the relay takeoff swimming platform top, others using a pressure sensitive piezo device. Experiments have been conducted with this latter method using load cells and accelerometers. It has been demonstrated that the accuracy of force measurement methods is limited by the fact that the swimmer may have one toe in contact with the relay takeoff swimming platform, but exert an immeasurable force against it. This results in the start being signaled before it has actually occurred. Because of this, FINA allows a tolerance of 0.03 second in relay exchange timing. In other words, a swimmer will not be disqualified unless the timing system shows a departure more than 0.03 second before the swimmer in the water touches the touchpad sensor. The “0.03 second” figure was established in tests using an Omega Sports Timing starting block, which showed that the signal from the relay takeoff swimming platform was consistently between 0.024 and 0.027 seconds before the actual departure. This is the Daktronics patent for their "contact based" relay exchange pad, which detects contact, and not pressure. Their (Daktronics) documentation says that they are accurate to 0.01 second. So -0.01 second is a DQ. -Rick

Good question. I can't find an explicit rule in the FINA rules and I doubt there is one. Here's the obvious rule about relay starts: SW 10.11 In relay events, the team of a swimmer whose feet lose touch with the starting platform before the preceding team-mate touches the wall shall be disqualified. I'm wondering if they use a tolerance value stated by the timing manufacturer to set the allowable negative reaction time. So, in Crocker's case maybe Omega published that the reaction times for this system were accurate to +/- 0.03 seconds, thus Crocker's -0.04 was an automatic DQ.

Thanks for the replies and the time and research that went into them ! It is frustrating (to me, anyhow) that we can't seem to locate FINA documentation of this procedure. Even if it is vendor specific (i.e. Omega or Daktronics, etc.), I would think FINA would have to publish guidelines. I may have to thirsty :)

Ande - That's not correct. The rules say that if you leave early, then you are disqualified. Period. The manufacturers publish different standards for what "early" means on their equipment. For Omega, their system apparently has difficulty detecting the departure from the starting block down to about 0.027 seconds. So on an Omega system, -0.03 seconds on an exchange is legal. This is because their system will sense "departure" about 0.03 seconds before contact is actually lost. Daktronics and Colorado Time Systems both publish a 0.00 margin. I.e., -0.01 is a disqualification on those systems. There is no rule that says that you're allowed to jump "a little bit". -Rick

Let me also clarify that there is a difference between the timing system detecting an early take-off, and actually being DQed. It all depends on your rule book. Under the NCAA rule book, if your exchange (subject to manufacturer's margin publications) is +0.09 (safe) through -0.09 (early), then the timing system wins always. I.e., if a Daktronics or Colorado relay exchange detects -0.01 in a NCAA meet, it is an automatic disqualification. Presumably, with an Omega system, -0.04 is an automatic disqualification. The USA Swimming and USMS rule books don't have anything nearly so clear. Use of relay exchange pads is subject to a little more interpretation. The guidance that we have used in New England, which we are told has become the defacto standard across the country, is that it requires a dual confirm still to DQ. The relay pad can be one half of a dual confirm. I.e., if automated equipment says "early", then it requires a human to dual confirm it. Generally, we have practiced the standard that the relay pad can also save you. For example, if two human officials call an early take-off, but the automated equipment says +0.01, then that overrules the officials. The FINA rule book doesn't get into specifics, but it appears that for things like the Olympics, that the automated equipment wins. I have not observed human officials doing visual relay exchange judging at the Olympics in some time. It appears that in a dispute, they would go to video replay. -Rick

In the patent application for the Daktronics relay exchange platform (patent 7403135), in the background for the patent, it says ... It has been demonstrated that the accuracy of force measurement methods is limited by the fact that the swimmer may have one toe in contact with the relay takeoff swimming platform, but exert an immeasurable force against it. ... The starting block measures the time when you stop applying force to the pad. That is not the same as the time when you actually no longer contact the top of the starting block. Whether -0.03 is the best safety margin, dunno. But a negative time does not necessarily mean the person left early.

The starting block measures the time when you stop applying force to the pad. That is not the same as the time when you actually no longer contact the top of the starting block. Whether -0.03 is the best safety margin, dunno. But a negative time does not necessarily mean the person left early. You should read the rest of the Daktronics patent application. Their patent is for a relay take-off pad that measures contact, not force. The quoted section is part of the support for why they wanted to come up with a way to measure contact, and _not_ measure force, because force is subject to those problems. -Rick

What I'll point out as an example... we have a set of Daktronics relay pads. In my experience, while testing... if there is an empty paper cup on the relay pad, and I pick up that cup... the pad will usually register that as a "departure". -Rick

Yeah, I guess the problem with a force transducer is that as soon as you have a positive acceleration in the vertical direction the pad will say you left the block even though this probably happens a few hundredths of a second before your feet actually leave the block.

Does anyone have a reference for an online copy of the current FINA rules? The FINA web site has information about ordering the printed rulebook, but it requires a bank transfer of funds (no checks or credit cards!). I found a couple copies of the 2005-2009 rulebook online. But I can't find the current 2010+ rulebook online anywhere. -Rick