Impact of Long-Term Swimming Exercise on Rat Femur Bone Quality

• Published in: Biomedicines 2024-01, Vol.12 (1), p.35
• Main Authors: Freitas, Laura, Bezerra, Andrea, Resende-Coelho, Ana, Gomez-Lazaro, Maria, Maciel, Leonardo, Amorim, Tânia, Fernandes, Ricardo J, Fonseca, Hélder
• Format: Article
• Language: English
• Subjects: Adipose tissue; Animals; Biomechanics; Bone density; bone growth; Bone mass; bone microarchitecture; bone mineral density; bone remodelling; Bone resorption; Bone turnover; Cancellous bone; Collagen (type I); Computed tomography; Cortical bone; Cross-sectional studies; Ethylenediaminetetraacetic acid; Exercise; Femur; Geometry; Laboratories; Mechanical properties; Medical equipment and supplies industry; Medical test kit industry; non-weight bearing exercise; Osteocalcin; Physical fitness; Porosity; Swimming; Tomography; Wheel running
• ISSN: 2227-9059; 2227-9059
• DOI: 10.3390/biomedicines12010035

Considering the conflicting evidence regarding the potential long-term detrimental effect of swimming during growth on femur quality and fracture risk, our aim was to investigate the effect of eight months of swimming on femur quality. Twenty male eight-week-old rats were assigned into a swimming (SW; = 10; 2 h/day, 5 days/week) or active control group (CG; = 10, housed with running wheel) for eight months. Plasma osteocalcin and C-terminal telopeptide of type I collagen concentrations (ELISA) were assessed at baseline, four, and eight months of protocol. Femur structure (micro-computed tomography), biomechanical properties (three-point bending), and cellular density (histology) were determined after the protocol. SW displayed a lower uncoupling index, suggesting higher bone resorption, lower empty lacunae density, cortical and trabecular femur mass, femur length and cortical thickness, and higher cortical porosity than CG ( < 0.05). Although both biomarkers' concentrations decreased in both groups throughout the experiment ( < 0.001), there were no significant differences between groups ( > 0.05). No differences were also found regarding biomechanical properties, bone marrow adiposity, and osteocyte and osteoclast densities ( > 0.05). Long-term swimming was associated with unbalanced bone turnover and compromised femur growth, lower femur mass, and deteriorated cortical bone microarchitecture. However, femur trabecular microarchitecture and biomechanical properties were not affected by swimming.