New research suggests that extra physical education classes can result in significant bone benefits in girls.

A seven-year study in four Swedish schools measured the impact of school-based exercise on children´s tibia cortical bone mass distribution.

A total of 170 children (72 girls and 98 boys) from one school were provided with 200 minutes of physical education per week, while three other schools (44 girls and 47 boys) continued with the standard 60 minutes. Participating schools were all within the same geographic area, with a similar socioeconomic and ethnic structure.

The results, published in the journal Calcified Tissue International & Musculoskeletal Research, show that an increase in school-based physical activity, initiated pre-puberty, was associated with higher tibia cortical bone strength accompanied by region-specific gains in cortical bone mass distribution in girls, but not in boys.

These gains were seen regardless of age, physical maturity, bone length, and weight.

Discussing the lack of effect on the bone health of boys in the study, the authors hypothesized that this could be due to the fact that the girls were generally less active in their spare time prior to the study and so the extra school-based physical activity was enough to result in positive bone adaptations.

Study author Dr Jesper Fritz of Lund University, Skåne University Hospital, Malmö, commented: “Findings of previous studies have shown that increased physical activity is associated with greater bone mass and strength in adolescents. The findings of this study specifically underline the benefits of increasing the amount of time dedicated to school physical education classes, particularly for girls, during the important stage of bone development around adolescence. Optimising bone mass and strength in youth has a positive impact on bone health and fracture prevention in adulthood.” %2Fs00223-016-0174-y