No gender-specific differences in mechanical efficiency during arm or leg exercise relative to ventilatory threshold

Area of Science:

• Exercise Physiology
• Human Performance
• Biomechanics

Background:

• Understanding sex-based differences in exercise economy and efficiency is crucial for optimizing training and performance.
• Previous research has yielded mixed results regarding sex differences in metabolic and mechanical efficiency during various exercise modalities.

Purpose of the Study:

• To compare exercise economy and mechanical efficiency (Gross Efficiency and Delta Efficiency) between men and women during arm cranking and leg cycling.
• To investigate these parameters at varying exercise intensities relative to the ventilatory threshold (Tvent).

Main Methods:

• Recreationally active men and women (n=9 each) with similar %VO2peak at Tvent performed arm cranking and leg cycling.
• Exercise was conducted at 70%, 85%, 100%, and 115% of mode-specific Tvent for 5-minute bouts.
• Economy (W/L/min), Gross Efficiency (GE), and Delta Efficiency (DE) were calculated.

Main Results:

• Leg cycling demonstrated greater economy and efficiency compared to arm cranking in both sexes.
• No significant sex differences were observed in economy, GE, or DE during either arm cranking or leg cycling.
• These similarities persisted across all tested exercise intensities relative to Tvent.

Conclusions:

• When matched for physiological intensity (similar %VO2peak at Tvent), men and women display comparable exercise economy and mechanical efficiency.
• The findings suggest that sex is not a determinant of efficiency differences in arm cranking or leg cycling under these controlled conditions.
• Future research could explore potential differences at sub-maximal or supra-maximal intensities or in different populations.