Standard CPR is performed with the person in supine position. Prone CPR or reverse CPR is CPR performed on a person lying on their chest, by turning the head to the side and compressing the back.
Non-spinal structural causes of weak legs may include sacroiliac joint pain syndromes and piriformis syndrome. Non-sciatica related sources of weakness in the legs may include diabetes, peripheral neuropathy and various circulatory and neurological conditions.
When your legs feel like jelly, standing can feel unusual. It may be accompanied by dizziness or balance issues that are either related to the weakness in your legs, or the direct result of anxiety causing other symptoms and conditions.