All cross-country skiing technique revolves around shifting the center of gravity. In double poling, this means lifting body weight upward and forward to generate force into the poles while ensuring that this force is effectively directed in the direction of travel with minimal energy loss. This may not sound particularly difficult. Most people can see the difference in harmony between the double poling technique of elite skiers and the more rigid and often unsynchronized movement pattern of a skier who is just learning to double pole.
However, pinpointing the key details in the movement that are crucial for improvement is significantly harder and requires a trained eye. It is also not always easy for a beginner to understand some of the terms ski coaches use to describe these details. This is where Skisens aims to help by breaking down the movement into measurable key metrics.
The power in double poling can be divided into three key metrics: frequency, impulse, and “pole direction efficiency.” The pole push accuracy can be described using the latter two. The biggest difference between an experienced double poler and a skier at a lower skill level is their ability to maintain impulse and direction at higher speeds and to increase these in uphill sections where more force is required. When a skier cannot maintain impulse and direction, they compensate by increasing frequency instead, which consumes more energy and ultimately limits speed as the body struggles to keep up.
Figure 1 below illustrates how these three key metrics develop as speed increases on a constant incline for 12 skiers in starting groups 0 and 1 at Vasaloppet. It is striking how all skiers lose directional efficiency as speed increases and how there is a maximum speed at which they struggle to maintain impulse. To compensate, they increase their poling frequency. However, when a skier rushes their movement to increase frequency, it almost always leads to further loss of impulse and direction, which quickly limits their maximum speed.

Figure 1: Development of impulse, pole direction efficiency, and frequency with increasing speed for 12 skiers in start groups 0 and 1 at Vasaloppet.
Figure 1 above illustrates the technical challenge a skier faces when trying to increase speed further at an already high pace. Another challenge that just as often determines ski races is the ability to increase power during acceleration or on steeper inclines. This can be tested by increasing the incline while maintaining a constant speed, as illustrated in Figure 2. There, we can see that the direction index increases slightly with incline, but primarily, impulse and frequency are increased to generate more power. Eventually, the skier is no longer able to increase frequency and impulse, which ultimately limits the maximum incline at which speed can be maintained. Notably, at this point, the skier has reached approximately the same frequency as in the test where speed was increased.

Figure 2: Development of impulse, pole direction efficiency, and frequency with increasing incline for 12 skiers in start groups 0 and 1 at Vasaloppet.
To gain a deeper understanding of how different skiers adjust their technique to adapt key metrics based on terrain and speed, we take a closer look at the force curve. It is particularly interesting to study how a skier manages increased speed versus increased incline. When the incline increases, the skier must generate more force.
Figure 3 shows force curves for an elite skier and a recreational skier at the same constant speed but across three different inclines. It is evident that the elite skier increases force as the terrain becomes steeper. For the recreational skier, this adaptation is much less pronounced. Initially, the force increases slightly, but there is also a significant loss in ground contact time, meaning that impulse does not increase and must instead be compensated for by a higher frequency.
As frequency increases, the skier can no longer generate enough force into the poles, causing the force to drop. This, in turn, forces the skier to further increase frequency, and before long, they are unable to manage the incline effectively.

Figure 3: Force curve for an elite skier (a) and a recreational skier (b) at three different inclines with constant speed.
If we instead look at the case where the incline remains constant while speed increases, a skier theoretically does not need to apply more force. The challenge, however, is to maintain the same force application as the time available for force generation decreases with increasing speed.
Figure 4 shows force curves for the same skiers as in Figure 3, but now under constant incline at three different speeds. A clear difference between the two skiers is that the recreational skier initially relies on a long ground contact time but with lower peak force. As speed increases, this long contact time can no longer be maintained. The skier must then increase peak force, which works reasonably well from level 1 to level 2. However, when speed is increased further to level 3, the skier is no longer able to generate higher peak force, leading to a loss of power—especially toward the end of the pole push, where it is crucial to maintain force for effective propulsion.
To compensate, the skier increases frequency, but this quickly leads to an inability to generate the necessary force to overcome resistance, ultimately forcing them to slow down.
From a ski technique perspective, the difficulties observed in the recreational skier’s force curves stem from an inability to move up and forward. Additionally, and more critically at higher speeds, they struggle to brace with their core, resulting in a significant loss of power toward the end of the pole push.

Figure 4: Force curve for an elite skier (a) and a recreational skier (b) at three different speeds on a constant incline.
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