Biomechanical factors that affect your skiing performance

Cross-country skiing is one of the most physically demanding sports out there. It requires not only exceptional fitness, but also technical skill and tactical finesse. Whether you're a beginner or an experienced skier, understanding the biomechanical factors that affect your performance can make a big difference in your riding. Here comes an in-depth review based on a comprehensive systematic review by Zoppirolli et al. (2020).

What is Biomechanics?

Biomechanics is the study of movements and the forces that affect those movements. In cross-country skiing, biomechanics is about how we move on skis and how we can optimize these movements to go faster, longer and with less effort.

Cycle length and cycle frequency: The key to speed and efficiency

Cycle length refers to the horizontal distance you cover with each complete movement cycle, from when you insert the bars and push off with them until you return to the starting position. A longer cycle length is often associated with higher speed and better efficiency. By aiming to extend your cycle length, you can cover more ground per movement and save energy in the long run.

Example : Imagine that you ride classic style and can increase your bike length from 1.5 meters to 1.8 meters per motion cycle. This means you cover 20% more ground with each move, which over time means you can go faster with less effort.

Cycle frequency (or cadence) is the number of movement cycles you perform per unit of time. A higher cycling rate can help you reach higher speeds, especially during sprints. However, cross-country skiers tend to choose a lower frequency for longer distances to optimize energy expenditure and improve endurance.

Example : During a sprint, you can increase your cycling rate to 60 cycles per minute compared to 45 cycles per minute during a longer race. This helps you maximize your speed during short intense periods and maintain endurance and efficiency over longer distances.

Joint kinematics: Optimal movement for maximum performance

Joint kinematics is about the movement pattern in the body's joints, such as elbows, knees and hips. By optimizing the angles and movements of these joints, you can improve power transmission and the efficiency of movement. Faster skiers often have greater range of motion in the knee and hip joints during the power phase, which results in more powerful pressure in the poles and in the push-off.

Example : During the power phase of the lunge (when you push the bars into the ground), a greater bending of the elbows and knees can lead to a more powerful push and thus better forward propulsion.

The body's center of motion (CoM): Stability and efficiency

The Center of Mass (CoM) , or the body's center of mass, is the point where your mass can be considered concentrated. Keeping the CoM stable and controlled during skiing reduces unnecessary vertical and lateral movement (up and to the side). This saves energy and improves your driving economy. Less deviation in the CoM means that more of your energy is used to propel you forward rather than up or to the side.

Example : By minimizing vertical movements during each skate cut, you can avoid wasting energy on lifting your body upwards and instead focus all your power on moving forward.

Propulsion kinetics: The force behind motion

Propulsion kinetics focuses on the forces generated and applied to propel you forward on the skis. Efficient power production and distribution through the poles and skis is critical to maximizing speed and endurance. Elite skiers produce higher power through their poles and skis and have better timing and coordination in their power generation.

Example : In diagonal skating (classical technique) it is important to time the pole grip and leg push phase perfectly to maximize power transfer and maintain a smooth and powerful forward drive.

Muscle activity (EMG): Timing and efficiency

Muscle activity , measured using electromyography (EMG), shows how and when different muscles are activated during skiing. By optimizing muscle activation and timing, you can improve both power development and endurance. Elite skaters have more efficient and synchronized muscle activation, which reduces energy cost per movement and improves endurance and speed.

Practical applications in training

To improve your performance on skis, you can focus on the following:

1. Extend your cycle length by working on your technique and strength. Practice taking longer cuts without losing your balance.
2. Optimize your cycling frequency depending on the length of the race and your goals. Practice increasing the frequency during short intervals and find a comfortable rhythm for longer distances.
3. Work on your joint movements to improve power transfer.
4. Stabilize your body's center of motion to conserve energy. Focus on keeping your body stable and minimizing unnecessary movements.
5. Focus on efficient power production - Practice applying the power at the right time and with the right intensity.
6. Practice synchronized muscle activation for better timing and efficiency. It is about being able to relax as much as possible in the muscles that should not be used to save energy.

Conclusion

By understanding and applying these biomechanical principles, you can take your cross-country skiing to the next level. Whether you're a beginner or an experienced skater, these insights can help you optimize your technique, improve your endurance, and increase your speed. So the next time you're out in the groove, think about how you can adjust your technique to get the most out of every stroke and cut.

Good luck on the tracks!

Reference:

Zoppirolli, C., Hébert-Losier, K., Holmberg, H.-C., & Pellegrini, B. (2020). Biomechanical determinants of cross-country skiing performance: A systematic review. Journal of Sports Sciences, 38 (18), 2127-2148. DOI: 10.1080/02640414.2020.1775375