Evaluating of the Axivity accelerometers algorithm in measurement of physical activity intensity in boys and girls

Abstract Background: Accelerometers are new but popular tools in measurement of physical activity level but most of them use the algorithms which are more suitable for adults rather than adolescents. Also accelerometers accuracy in assessing physical activity intensity in boys and girls is widely unknown. Therefore, purpose the current study was to evaluate the validity of the Axivity accelerometers in relation to establish algorithm in the measurement of physical activity intensity in boys and girls. Methods: A total of 143 participants recruited from a local school in Oxfordshire and 119 of them (84 boys and 35 girls, age (12.71 ± 0.46)) completed the shuttle run test while wearing an AX3 accelerometer. Signal Vector Magnitude (gravity-subtracted) (SVMgs) and Metabolic equivalent (MET) values were calculated for both of boys and girls. Results: The study result showed that girls had significantly higher SVMgs value (P< 0.05) while according to the standard equations, girls have lower VO2max and MET in each shuttle run lap. Conclusion: This study result suggest that different algorithms might be necessary to measure physical activity in different genders.