Question 11- 12. Choose A, B or C as the best answer.11. For elderly athletes, a decrease in bone density may:

Question

BlackTom AI · Accepted Answer

Bone density reflects the amount of mineral (mainly calcium and phosphate) in bone and is a primary determinant of bone strength. When bone density decreases (osteopenia progressing to osteoporosis), bones become more porous, less stiff, and less able to withstand normal forces, which increases the likelihood of fractures and other skeletal injuries.

1) Relevant knowledge points and concepts
- Bone remodeling: lifelong balance of osteoblast (bone formation) and osteoclast (bone resorption) activity; age and hormonal changes can shift this balance toward resorption.
- Structural consequences: lower mineral density and deterioration of trabecular architecture reduce mechanical strength.
- Clinical outcome: reduced bone strength manifests as increased fracture risk from falls or even minimal trauma.

2) Step-by-step reasoning
- Step 1: Aging and hormonal changes often reduce bone mass (reduced osteoblast activity, increased osteoclast activity).
- Step 2: Reduced bone mass lowers the cross-sectional density and integrity of cortical and trabecular bone.
- Step 3: With diminished structural support, normal loads or minor impacts are more likely to exceed bone failure thresholds.
- Step 4: Exceeding those thresholds produces fractures and other skeletal injuries, so the probability of injury rises.

3) Calculations
- No numerical calculation is required for this conceptual question.

4) Why the correct answer is correct
- Option b ("increase the probability of injuries") directly follows from the mechanical weakening of bone due to lower density: weaker bones break more easily, so injury probability increases.

5) Why the other options are incorrect
- Option a ("reduce muscle mass") describes sarcopenia, which is loss of muscle tissue; while coexistence with bone loss is common, decreased bone density does not directly cause muscle mass loss.
- Option c ("speed up recovery") is false because lower bone density typically complicates healing and increases recovery time after fractures; healing is not accelerated by weaker bone.

Conclusion: Decreased bone density in elderly athletes makes bones more fragile and thus increases the probability of injuries, so the correct answer is b.

Question 11- 12. Choose A, B or C as the best answer.11. For elderly athletes, a decrease in bone density may:单项选择题

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