Which of the following is a noted disadvantage of elevated vacuum systems?

The noted disadvantage of elevated vacuum systems being heavy weight from the pump is significant because these systems rely on a pump to create and maintain a vacuum seal within the prosthesis. The pump adds additional weight that can be cumbersome for the user, especially in comparison to lighter prosthetic systems. This added weight can contribute to fatigue during use and may affect the overall comfort and mobility of the person wearing the prosthesis.

Understanding the context of the other options helps clarify why they do not represent disadvantages. Improved proprioception is actually considered a benefit as it allows users to have a better sense of their body position, enhancing balance and coordination. The ability to use subischial trimlines is also considered an advantage because it allows for increased mobility and comfort, particularly for those who require a more flexible design. Furthermore, effective control of rotation is another benefit of elevated vacuum systems because it enhances stability and alignment of the prosthetic limb, which contributes to user confidence during various activities.