A suitable body pattern is necessary for health. A wrong development of it could determine disorders in mental and physical areas (Ballesteros, 1982). To be active since childhood constitutes a primary factor for developing a good Body Mass Index (BMI) and body image, the main components of body pattern (Piéron, 2005).

To evaluate levels of physical activity (PA) and the relation with body pattern for the prevention of disorders in spanish youth.

3685 subjects aged 8 to 24 were selected from various educational institutions of Granada, Spain. Researchers took antropomethric measurements and submitted pupils to IPAQ questionnaire (Booth, 2000) and Body Image Assessment Scale (Thompson & Grey, 1995).

Results showed that PA levels constantly decrease from Primary School until University (p = .001), and BMI increased at the same time. Body image kept constant values at each age range. We found significative correlations between PA and BMI and between BMI and body image (p = .001), but not between PA and body image.

This lack of correlation could mean that subjects have a wrong perception of their body, since they consider themselves healthy despite their BMI raise. This could explain the reduction of practice. This situation could determine the progressive onset of sedentary behaviors and mental disorders as anorexia or bulimia. In the future, Physical Education teachers should aim their classes at developing the perception of body through PA, to make pupils be active and to give them the basis for a suitable construction of body pattern.