Left, Right, or Straight: Leg Analysis #8

The first long leg  on long distance in M21E class of 'Spring Spartacus' event in Hungary was a 100% delicious! 

This leg 13-14 presented two main options, but due to long way around on left route, many participants opted for a shorter yet higher altitude right route.

Let see this leg in more detailed.

In the initial assessment, the evaluation of the relative positioning of the controls in terms of altitude plays a crucial role. At a cursory glance, it is not challenging for an experienced orienteer to discern that the controls are roughly at the same elevation. However, it's worth noting that  Control 14 sits even 45 meters lower than Control 13.

The unspoken rule of route selection is that 'if there is no need to gain elevation, it's better to avoid doing so.' Therefore, when control points are at the same altitude, routes on flat terrain are always viable options. In our case, the left route, which bypasses all the ravines and gullies, is particularly advantageous, especially since it allows for the use of the road (with climb about 30 meters).

The route on the right is shorter, but it includes two additional climbs of 50 meters each and one steep descent, which also consumes time. The first climb is along the road, which is not too challenging. However, the time will be spent on the second one 'in the front,' which will be on foot

The shorter routes are highly questionable due to a very 'slow' section during the traverse of the slope on control approach, as well as an overgrown clearing at the foot of the slope.

When comparing the right and left routes, one should not focus solely on how much the left route deviates from the direct line, but rather on how much longer it is compared to the right route.

We have a difference in route length of 600 meters (3000 meters for the left route versus 2400 meters for the right route).

And then it is this difference that is 'weighed' against other factors. On the other side of the scale, we have two additional slopes to climb, the need for consistently focused orienteering (which may hinder route planning for next legs), and, in addition to these, a more challenging approach to the control compared to the route from above.

At the same time, we should consider that gaining extra altitude may have a negative impact towards the end of a long distance race, when there might not be enough energy to keep a high pace. This could potentially lead to a loss of time.

Taking all factors into account, my preference is for the left-hand route .

Then it remains only to decide the locations where we have potential variations (to make a macro-choice) in how to execute the left route.

Let's define a point where we will definitely run, regardless of the specific execution of the left route. It's an turn of the road.

Now, let's mentally place a control there. Let's evaluate this leg from Control 13 to this new control. There's less inclination to run straight ahead now, isn't it? now it is easy to see that running straight ahead seems more challenging

The next question is how to navigate from control 13 onto the road.  should we cutting straight through the ravines? We'll also place a virtual control at the point on the road where we intend to hit road after shortcut and examine this leg separately.

We address similar doubts, such as whether to cut in the middle of running on the road, using the same approach. 

As a result of these operations, we conclude that the optimal route is the one that bypasses all the ravines on the left

Now the results of the men's elite:

best time on the 13-14 leg: Tobias Alstad 12.50 (3rd place overall);

Simon Imark - best on right route with 13.36 (2nd place overall);

the winner of the course  Topi Syrjäläinen was running on the left with 13.07

Emil Svensk (7th place overall) attempted a shorter route. and this resulted in a 14.06 on the leg (1.15 lost and a 10th place in this leg).

source: livelox 

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Aleksandr Alekseyonok, April 9, 2024.