Assess Whether Knowledge by the Younger of the Function of the Accelerometer Determines Its Amount of Physical Activity

Assess Whether Knowledge by the Children and Adolescents of the Function of the Accelerometer Determines Its Amount of Physical Activity

Eighty healthy youngsters, aged 10-18 years, will be equally randomized between the blinded and the non-blinded group. The blinded subjects will be informed that we were testing the reliability of a new device for body posture assessment and these youngsters will did not receive any information with regards to physical activity. Conversely, the non-blinded subjects were informed that the device was an accelerometer that assessed physical activity levels and patterns. Participants will be instructed to wear the accelerometer for 4 consecutive days and to keep a non-wear log diary over the 4 day-monitoring. The overall duration and the duration relative to the quality of the physical activity patterns (sedentary, light, moderate, vigorous and moderate to vigorous) were computed for each group during the 4-day monitoring, then compared between the two groups using the Student's t test.

Inclusion Criteria:

• 10-18 years old adolescent
• normal clinical examination,
• normal nutritional status at baseline defined by a weight / height ratio between - 2 and + 2 DS DS

Exclusion Criteria:

• abnormal ECG
• known chronic disease
• acute infection dating back at least a week.