Publication by Mitchell JA, Chesi A, McCormack SE, Cousminer DL, Kalkwarf HJ, Lappe JM, Gilsanz V, Oberfield SE, Shepherd JA, Kelly A, Grant SFA, Zemel BS. This study aimed to determine if replacing time spent in high- and low-impact physical activity (PA) predicts changes in pediatric bone mineral density (BMD) and content (BMC).