About the 'Lap Combat' method - 'Sakurai-Tori O-Lap analysis method'

The orienteering Elapse-lap time analysis method 'Sakurai-Tori O-Lap analysis method' was (originally, first) devised in 1996. It has been revised several times since then and is still under cooooontinuoeus development.

Taro SAKURAI is Japanese, lives in Tokyo and will turn 29 this year. Occupation: NORMAL map making.

Kazushige HATORI (tori) is me. lives upperpart of Tokyo age 34 in 2000. Local elite orienteer, international mapper?, and I'm involved in every o-thing. Occupation: computer engineer working for Canon.

The main purposes of the method are to provide your race speed compared with ideal winning time and to estimate your mistake ratio and lost time both in each leg (between controls) and in the whole race.

From the statistical point of view, the method is quite simple, and not necessarily based on real statistics. However, it seems to work very well practically. ......to analysis of your race and lead to higher level of your orienteering skills.

Please feel free to ask me, , anything you are interested in. Any suggestion and question will be appreciated.

In the following items, each method will be explained.

Even if you won the race, was your winning time really the best possible time? (there is always one person who wins therace i think) or Was the winning time really the best possible time ? How to know the best time of the race ? By Adding up the best lap of each leg ? It seems always be too fast for all participatorssince no one of them can run even if all the route would be taped.

The best lap time of one leg seems to be too fast. Well then, is the second best lap time good for analysis ? Also, the second best lap time is not necessarily always the second one, but is usually equivalent to best, or sometimes the 3rd time. It means that the 1st, 2nd and 3rd lap time alone are not always reliable for analysis.

However, is the average of best 3 laps (Ave3) good ? YES. Kazushige Hatori, discovered that there is only a little difference between the total sum of average time (Ave3) for all legs and the race winning time minus the winner's mistake time. Experience shows that this supposition always fits to the result of an orienteering race.

Use of Ave3 is the first key point of 'Sakurai-Tori O-Lap analysis method'. Statistically speaking, normalization of each leg is done by using the best 3 laps.

As explained above, the ideal winning time is computed (evaluated) as the sum of the average of the best 3 laps (Ave3) in each leg.

It is quite easy to obtain the logical leg length calculated as a ratio between Ave3 of that leg and the ideal winning time. When you want to draw a graph of dependance of competitor's time on the cruising distance from start, you easily get the virtual but logically precise distances here.

We shall compare your leg time with Ave3 for each leg. We propose that the speed index of each leg should be calculated as ( your time ) / Ave3 * 100. In the case of getting the best lap among all competitors, you could get the speed index below 100. Sometimes, in case your time is the 2nd one, your speed index will be near 100. That would sound like good race at least in the leg.

Another hypothesis is needed in order to acquire your cruising speed. The next assumption is that 'you have made only negligible mistakes in at least half of the whole race.'

Firstly, find the leg with the best (smallest) speed index in your list from 4., then get its leg ratio and its time (or lap). Secondly, same as in above, find the second speed index and sum up the leg ratios and the leg times. Repeat this iterative process until the sum of the leg ratios exceeds 50%.

Suppose that you get 53.245% and 43'25". That means you ran 53.245 % of race in 43min 25sec, while doing only little mistake. To know your ideal finishing time, you divide 43'25''sec by 53.245% = 81min32sec!

You can easily get the speed index from (your ideal finish time)/ (ideal winning time) * 100.

Do you have a good cruising index, near 100? Your index shows a possible shortage of your physical skill needed for winning the race. For the purpose of achieving your target, you will know whether your physical potential is enough or not.

Did you get the index below 100 in spite of not winning the race ? Then you should refer to the following analysis indexes.

To analyse your race, you should think about the amount of mistakes.

The difference between your race result and your ideal finishing time (see5.1) is your total mistake,
your total mistake time = (your race result) - (your ideal finishing time).

And in the same way,
your mistake ratio = (your total mistake time) / ( your race result) *100

Do YOUR total mistake time and mistake ratio sound good to you? Or are these values rather beyond your imagination (tooo bigger mistake) ? Experience shows that world top elites can achieve their own mistake ratio to be as low as 3-4%. How was your race today ?

You can get the mistake time in each leg. This is very effective to analyse your race result.

You can get the ideal time of each leg from each leg's (Ave3) * your cruising speed index. For each leg,
your mistake time = your time of that leg - (Ave3 of that leg) * (your cruising speed index)

Sometimes you may get negative mistake time. It means you should cheer yourself seeing your average as you your good map reading, planning tactics and route choice led to virtually no mistake. Great!