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

• Published in: Medicine and science in sports and exercise Vol. 53; no. 6; p. 1179
• Main Authors: Warden, Stuart J, Wright, Christian S, Fuchs, Robyn K
• Format: Journal Article
• Language: English
• Published: United States 01.06.2021
• Subjects: Absorptiometry, Photon; Adaptation, Physiological; Bone Density; Cortical Bone - anatomy & histology; Cortical Bone - physiology; Cross-Sectional Studies; Diaphyses - anatomy & histology; Diaphyses - diagnostic imaging; Diaphyses - physiology; Female; Humans; Radius - anatomy & histology; Radius - diagnostic imaging; Radius - physiology; Running - physiology; Tennis - physiology; Tibia - anatomy & histology; Tibia - diagnostic imaging; Tibia - physiology; Tomography, X-Ray Computed; Young Adult
• ISSN: 1530-0315
• DOI: 10.1249/MSS.0000000000002571

Physical activity benefits bone mass and cortical bone size. The current study assessed the impact of chronic (≥10 yr) physical activity on trabecular microarchitectural properties and microfinite element analyses of estimated bone strength. Female collegiate-level tennis players (n = 15; age = 20.3 ± 0.9 yr) were used as a within-subject controlled model of chronic unilateral upper-extremity physical activity. Racquet-to-nonracquet arm differences at the distal radius and radial diaphysis were assessed using high-resolution peripheral quantitative computed tomography. The distal tibia and the tibial diaphysis in both legs were also assessed, and cross-country runners (n = 15; age = 20.8 ± 1.2 yr) included as controls. The distal radius of the racquet arm had 11.8% (95% confidence interval [CI] = 7.9% to 15.7%) greater trabecular bone volume/tissue volume, with trabeculae that were greater in number, thickness, connectivity, and proximity to each other than that in the nonracquet arm (all P < 0.01). Combined with enhanced cortical bone properties, the microarchitectural advantages at the distal radius contributed a 18.7% (95% CI = 13.0% to 24.4%) racquet-to-nonracquet arm difference in predicted load before failure. At the radial diaphysis, predicted load to failure was 9.6% (95% CI = 6.7% to 12.6%) greater in the racquet versus nonracquet arm. There were fewer and smaller side-to-side differences at the distal tibia; however, the tibial diaphysis in the leg opposite the racquet arm was larger with a thicker cortex and had 4.4% (95% CI = 1.7% to 7.1%) greater strength than the contralateral leg. Chronically elevated physical activity enhances trabecular microarchitecture and microfinite element estimated strength, furthering observations from short-term longitudinal studies. The data also demonstrate that tennis players exhibit crossed symmetry wherein the leg opposite the racquet arm possesses enhanced tibial properties compared with in the contralateral leg.