How does pole length affect lower back muscle activity at different inclines and skiing intensities during double...

Area of Science:

• Sports Science
• Biomechanics
• Exercise Physiology

Background:

• Double poling (DP) is a key technique in cross-country skiing, but its biomechanical demands on the lower back are not fully understood.
• Understanding muscle activation patterns during DP is crucial for preventing low back pain in elite athletes.

Purpose of the Study:

• To investigate the effects of pole length, incline, and skiing intensity on lower back muscle activation in elite cross-country skiers.
• To identify biomechanical factors contributing to the risk of low back pain during DP.

Main Methods:

• Eleven elite cross-country skiers completed DP trials on a treadmill with varied incline and intensity.
• Surface electromyography measured erector spinae muscle activity; motion capture analyzed lower back kinematics.
• Data were analyzed to assess muscle activation in relation to kinematic variables and skier demographics.

Main Results:

• Female skiers exhibited significantly higher overall lumbar erector spinae muscle activation compared to male skiers (26-28% MVC vs. 15-22% MVC).
• No significant correlations were found between muscle activation and lower back-pole moment arm or hip angle.
• Muscle activity patterns varied between genders, indicating potential sex-based biomechanical differences.

Conclusions:

• Female skiers may have a greater susceptibility to lower back issues due to higher muscle activation during DP.
• Training programs and equipment should be adapted to reduce lower back stress, particularly in high-intensity, flat terrain conditions.
• Further research is needed to explore gender differences and biomechanical factors influencing back muscle engagement in cross-country skiing.