Article

The purpose was to compare psychophysiological responses between healthy male and
female workers during dynamic pushing. Using a psychophysical approach, 27
participants chose an acceptable force that they could push over a 7.6m distance
at a frequency of 1 push per min on a treadmill. On a separate day,
cardiopulmonary (e.g., whole-body oxygen uptake, heart rate, ventilation volume)
and muscle metabolic measurements (change in muscle blood volume [DeltatHb] and
Tissue Oxygenation Index [TOI]) from the right and left gastrocnemius muscles
were collected simultaneously while participants pushed the previously chosen
acceptable force on the treadmill at a similar frequency and distance for 2h.
Results showed no significant difference between men and women for integrated
force exerted on the instrumented treadmill handle and cardiopulmonary responses.
In contrast, women demonstrated 45.7% lower DeltatHb but 3.6% higher TOI in the
gastrocnemius region as compared to men, suggesting a lower hemoglobin
concentration in women and high venous oxygen saturation during pushing. When
DeltatHb and TOI were corrected for both body mass and pushing force, the
disparity in gender was retained, implying an increased muscle oxygen saturation
per force development in women than men during pushing. In the left gastrocnemius
region, DeltatHb was 60% lower and TOI was 5.7% higher in women than men,
suggesting an uneven muscle loading during pushing. Overall, the gender
similarity in cardiopulmonary responses versus disparity in muscle metabolic
responses suggest the importance of evaluating human performance during physical
work at both whole-body and localized muscle levels.
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