Cheltenham Triathlon Club
For experienced and aspiring triathletes

In response to several questions from members, the colour coded notes in the results published are meant to be a bit of fun, however there is a serious scientific point relating to the difference between your fastest and slowest 100m splits, if you are interested read on.

The 1st 100m split should be the fastest as you are fresh at the start, which could be measured by your blood, lactate level which will be about 1mmol/litre. Over the first 100/150m this will quickly rise to the point where it is on the edge of going exponential (about 3 to 4mmol/l). Those who went off too fast know what it feels like when it does goes exponential.

If you continue to work hard close to the edge, your lactate will stay at this level and your splits will drift off slightly depending on your endurance fitness.

Over the last 100/150m you can go harder and let your lactate go exponential as long as you can hold on to touching the wall at 1500m, the last 100m split should be your 2nd fastest as a result but you will be exhausted at the end and your lactate at 6 to 8mmol/l. Obviously we are talking about a 1500m TT, not at the start of a triathlon.

These points are all illustrated in the timing slip for Grant Hackett when he broke the world record (which still stands today) the difference between his fastest and slowest is just under 10% of his average lap time which is what we use as our "green" zone.

Several people had slower times than expected, this is probably because you weren't working hard enough and your lactate was drifting around 2 to 3mmol/l. You need to be working as hard as you would be in a 5k run race or 10 mile bike time trial.

Anyone discouraged should take heart from the fact that Grant Hackett would have been much slower in the Lido, choppy water caused by the square sided walls and the drag from the shallow bottom in half the pool being the main factors. Anyone still reading I trust you have found this useful.

Split Distance(m)Split Time(s)
100 54.2
200 58.2
300 58.8
400 58.9
500 58.6
600 58.6
700 58.5
800 58.5
900 58.6
1000 58.7
1100 58.8
1200 59.0
1300 59.0
1400 59.4
1500 56.7
total 14.34.5

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