Accuracy and cross-validity of the Xiaomi Mi Band 2, 3, 4, and 5 wristbands in evaluating physical activity in adolescents according to WHO 2020 guidelines: School-Fit study ( vol 65 , 1682 , 2025) - Mayorga-Vega, Daniel; Guijarro-Romero, Santiago; Casado-Robles, Carolina; Viciana, Jesus (Journal Of Sports Medicine And Physical Fitness, 2025)