Why does Manual Handling contribute to increasing the possible risk of patients getting pressure sores?

Any hints or advice to get me started in right direction would be great!

Hi, A pressure area is defined as pressure sores or bed sores caused by an area of the skin that breaks down. Usually the causation is either from pressure, where the weight of the body is pressing down on the skin, from shear, where layers of the skin are forced to slide, for example, when pulling a person up the bed without using appropriate equipment, or from friction, where the skin rubs together.
Also

www.inclusion.me.uk/blog/pressure-relief/