Bone Microarchitecture and Strength Adaptation to Physical Activity: A Within-Subject Controlled HRpQCT Study

Area of Science:

• Bone Biology and Physiology
• Skeletal Adaptations to Mechanical Loading
• Sports Medicine and Biomechanics

Background:

• Physical activity is known to positively influence bone mass and cortical bone dimensions.
• Long-term effects of chronic physical activity on trabecular bone microarchitecture and bone strength require further investigation.

Purpose of the Study:

• To assess the impact of chronic (≥10 years) physical activity on trabecular microarchitectural properties.
• To evaluate microfinite element analyses of estimated bone strength in response to long-term physical activity.

Main Methods:

• A within-subject controlled model using female collegiate tennis players (n=15) with unilateral upper-extremity activity.
• High-resolution peripheral quantitative computed tomography (HR-pQCT) assessed bone differences in the dominant (racquet) vs. non-dominant arm.
• Cross-country runners (n=15) served as controls, with assessments on distal tibia and tibial diaphysis in both legs.

Main Results:

• The racquet arm's distal radius showed 11.8% greater trabecular bone volume/tissue volume and enhanced trabecular parameters (number, thickness, connectivity).
• Predicted load to failure was 18.7% higher in the racquet arm's distal radius and 9.6% higher in the radial diaphysis.
• The tibial diaphysis in the leg opposite the racquet arm demonstrated a larger size, thicker cortex, and 4.4% greater strength compared to the contralateral leg.

Conclusions:

• Chronic physical activity significantly enhances trabecular microarchitecture and estimated bone strength, supporting findings from shorter-term studies.
• Tennis players exhibit crossed symmetry, with the leg opposite the racquet arm showing improved tibial properties compared to the contralateral leg.