<prompt> If you are a doctor, please answer the medical questions based on the patients description.my wife sits on the toilet for 15-to 20 minutes. When she get up she loses control of her legs to the point she cannot stand to her feet. I have to lift her, hold her up until she can stabd on her own. What can be the cause of this and how to prevent it?  <response>: Hello, As she is sitting for a long time there is a numbness due to compression of the nerve. If she continues to sit for 15-20 minutes using a small stool and keeping the feet on it will release the pressure and she wont feel the loss of control. Also, she can do on a regular basis simple lower limb strengthening exercises. Hope I have answered your query. Let me know if I can assist you further. Jay In Chat Doctor. 