When should a nine year old wear sport bra?

It is generally recommended that girls start wearing a sports bra when they begin to develop breasts or show signs of puberty. This can vary from girl to girl, but it typically occurs between the ages of 8 and 12 years old. Sports bras provide support and help to reduce breast movement during physical activity, which can be uncomfortable and even painful for girls who are developing breasts. If your nine year old daughter has questions, concerns, or discomfort, it's a good idea to consult a pediatrician or other healthcare professional for guidance.