Peak bone mass acquisition through childhood and adolescence has been associated with lower risk of osteopenia and osteoporosis in the elderly. The main factors that influence bone mass are the non-modifiable, such as genetics, ethnicity and sex, and the modifiable ones which are nutrition and physical activity or exercise. In the literature are references that demonstrates positive effects of high physical activity, adequate intakes of macro- and micronutrients on bone mass both in adults and in children. Bone mineralization is more adaptive in childrens' growing bones and this is an opportunity for stronger effects by mechanical stimuli during physical activity. The presence of a diet complete of nutrient intakes seems to strengthen the effects of mechanical loads on bone growth and mineralization. The present trial aimed to evaluate the effects of physical activity and nutrition intakes on bone mass in pre-pubertal children.

The sample of this study was healthy pre-pubertal boys and girls (N=210) who had training age 0-1 years. Data collection included anthropometric measurements, blood sampling, body composition, bone measurements and physical performance measurements. Nutritional intake was recorded for seven consecutive days in order to evaluate nutrient intakes using an appropriate software and habitual physical activity was measured for the same days using accelerometers. Pubertal stage determined by Tanner scale. All measurements were made only once at the beginning of school year.

Inclusion Criteria:

• were 6-12 years and pre-pubertal
• were healthy and had no prior bone fractures or related surgical operation
• their body fat was <30%, e) had no history of growth irregularities
• were not receiving agents or drugs that affect bone tissue (e.g. Gonadotropin-Releasing Hormone (GnRH) agonists, antiresorptive, bisphosphonates, etc.)

Exclusion Criteria:

• had prior bone fractures or related surgical operation
• their body fat was >30%
• had history of growth irregularities
• were receiving agents or drugs that affect bone tissue (e.g. GnRH agonists, antiresorptive, bisphosphonates, etc.)

Primary schoolchildren (boys and girls) aged 6-12 years and were at pre-pubertal stage.