Biomechanically influenced differences in O2 extraction in diagonal skiing: arm versus leg

Area of Science:

• Exercise Physiology
• Sports Science
• Biophysics

Background:

• Cross-country skiing involves significant upper and lower body exertion.
• Understanding regional differences in oxygen metabolism and lactate accumulation is crucial for optimizing performance.

Purpose of the Study:

• To investigate disparities in arm and leg oxygen extraction and lactate levels during skiing.
• To determine if muscle activation and force production influence these differences.
• To assess the impact of reduced exercise intensity on these physiological responses.

Main Methods:

• Nine elite male cross-country skiers performed diagonal skiing at 90% and 70% of their maximal oxygen uptake (V˙O2max).
• Blood samples were analyzed for gases and lactate.
• Electromyography (EMG) measured muscle activation, and leg/pole forces were recorded.

Main Results:

• Legs exhibited higher oxygen extraction than arms at both intensities.
• Arm EMG activity and pole ground contact time were greater than corresponding leg values.
• Subclavian (arm) lactate concentration was higher but decreased more with reduced intensity compared to femoral (leg) lactate.

Conclusions:

• Higher arm muscle activation and longer pole contact time contribute to lower arm oxygen extraction and elevated lactate.
• Reduced exercise intensity leads to more significant lactate recovery in the arms than the legs.
• These findings highlight distinct physiological demands on upper and lower body musculature in skiing.