George is a 12-year-old male brought to the clinic by his father and wants to start playing football and needs a preparticipation physical examination (PPE). He is an established patient in your practice and his last health maintenance exam was at 11 years of age. In reviewing his health history, you note that he has sickle cell trait but otherwise healthy. During his exam, you auscultate a Grade I murmur, and the remaining exam is normal. Dad asks if you will clear George to start football practice tomorrow. Would you clear George? Why or why not? Are there any specialists George needs to see before clearance? What are some of the preventive measures you would discuss with George and his father related to playing sports, specifically football?