Quantifying bone-relevant activity and its relation to bone strength in girls

Area of Science:

• Pediatric bone health
• Exercise science
• Biomechanical assessment

Background:

• Physical activity (PA) is crucial for bone development in children.
• Current methods for measuring PA lack consensus on their effectiveness in predicting bone strength.

Purpose of the Study:

• To compare four physical activity (PA) quantification methods: pedometer, 3-dimensional PA recall (3DPAR), bone-specific PA questionnaire (BPAQ), and past year PA questionnaire (PYPAQ).
• To evaluate the ability of these PA measures to predict indices of bone strength in young girls.

Main Methods:

• 329 girls (aged 8-13) underwent pedometer assessment, 3DPAR, BPAQ, and a modified PYPAQ.
• Bone strength index (BSI) and strength-strain index (SSI) were measured using peripheral quantitative computed tomography.
• Correlations and hierarchical multiple regression analyses were used to assess relationships between PA measures and bone strength indices.

Main Results:

• The PYPAQ score was significantly associated with BSI and SSI at all measured sites, explaining more variance than other PA measures.
• Pedometer steps and 3DPAR scores showed significant associations with specific metaphyseal bone strength indices.
• The BPAQ score did not show significant associations with bone strength indices.

Conclusions:

• A modified PYPAQ, considering PA duration, frequency, and load, demonstrated superior prediction of bone strength indices compared to other methods.
• This suggests the PYPAQ is a more effective tool for assessing PA's impact on bone strength in young girls.