Using CheckMate's "Leap Start" Feature
If you blow the start of your race by forgetting to press the start button at the 1:00 or 0:00 marks, don't worry. Your CheckMate will still keep track of the miles you have ridden (silently, behind the scenes).
At some convenient place, say the 2.9 mile marker, press and hold the main thumb button and LEAP will display, with a time 00:00 (mm:ss). Check your wristwatch or ask a fellow rider for the time THAT YOU HAVE BEEN RIDING. In other words, time since YOUR key time. For example, you arrive at the 2.9 mark and you check your wristwatch (or another rider) and the time is 08:07:10 (hh:mm:ss). You have been riding for 7m10s. You would then enter 08:00 (mm:ss--anext whole minute up) into the computer. Short hold the bottom button to accept that time. Then bump the bottom button again to enter standby. Now, at the exact moment the wristwatch turns to to 08:08:00, press the main button and you will be racing. Notice that the mileage will have jumped forward to the actual mileage you rode while the computer was in standby. It should be very close, unless you rode a long way with it in standby, and you can make your final adjustments now, to 2.9.
Practice once or twice at home, and it's really quite easy. You can also do this at a check, using the clock at the check. You'll likely lose some points, but will have a chance to run the rest of the race perfectly.