How does oxygen uptake during submaximal arm work compare to that of leg work?

The correct choice reflects a fundamental understanding of the physiological differences between submaximal arm work and leg work during exercise. When engaging in submaximal arm exercise, oxygen uptake is generally observed to be lower than that during leg exercise. This lower oxygen uptake can be attributed to several factors, such as a smaller muscle mass being used in arm exercises compared to leg exercises. Since the legs contain a larger muscle mass and are often more conditioned for aerobic activities, they require more oxygen to sustain exercise.

Additionally, during leg work, more major muscle groups are activated, leading to a greater overall demand for oxygen. Thus, the difference in oxygen uptake between arm and leg work highlights the efficiency and effectiveness of using larger muscle groups engaged in leg activities compared to the smaller muscle groups engaged in arms. While individual fitness levels can affect overall exercise performance, the inherent metabolic differences between upper and lower body exercises primarily dictate this response. Therefore, recognizing the distinct oxygen uptake responses helps in designing effective training programs that consider the physiological capacities of different muscle groups.