Walking voltage of the human body

Hello everyone, I have a question regarding the walking voltage of the human body. The surface resistance and grounding resistance of our EPA floor meet the ESD standards, and the personnel shoes also meet the requirements. However, when I test the walking voltage, I measure a value greater than 100V. How should I improve this? Additionally, we hope to control the walking voltage of the human body within 50V. Do you have any suggestions for this?