• Distance running can decrease thigh size.runner girl image by jimcox40 from Fotolia.com
  
  

23.6 Inches is the Average Thigh Size

• The average thigh size is 23.6 inches in circumference, according to a 2009 study done by the World Health Organization. The study participants were both women and men of various heights.
  
  

It Depends on the Person

• The size of a person's thighs will vary depending on their sex, exercise and eating habits, and genetics, states Columbia University Health Services. "People may be genetically predisposed to have strong leg muscles in their thighs," the website states. The size of your thighs is not related to your height.
  
  

Bottom Line

• There is no "ideal" thigh size. If your lifestyle includes healthy eating habits and regular physical activity, and you are not obese, don't worry about the size of your thighs. The World Health Organization study even found that larger thighs can decrease your risk of heart disease. According to Columbia University, exercise--such as heavy weight lifting--tends to increase thigh size. Distance running, on the other hand, can slim thighs down.