下列哪項活動建議 70 歲客戶執行，以維持骨質密度並預防骨質疏鬆？
Which of the following activities is recommended for a 70-year-old client to maintain bone density and prevent osteoporosis?
- ADeep water aerobics深水有氧运动
- BStationary cycling固定式脚踏车
- CWeight-bearing exercises such as walking✓ 正解负重运动，例如步行
- DSwimming laps for 30 minutes游泳30分钟
骨質疏鬆症的預防核心在於增加骨密度，而負重運動（Weight-bearing exercises）是透過地心引力對骨骼施加機械性壓力，刺激成骨細胞（Osteoblasts）活性。對於 70 歲長者，走路、快走、爬樓梯或舉輕量啞鈴等都是良好的負重運動。游泳與水中運動雖能保護關節，但因水的浮力抵銷重力，無法有效訓練骨密度，故對預防骨鬆效果有限。
The cornerstone of osteoporosis prevention is increasing bone mineral density, and weight-bearing exercises do this by applying mechanical stress to bone against gravity, which stimulates osteoblast activity. For a 70-year-old, walking, brisk walking, stair climbing, and light dumbbell work are all suitable weight-bearing activities. Swimming and aquatic exercises are joint-friendly, but because the buoyancy of water offsets gravity they do not effectively train bone density and have limited benefit for osteoporosis prevention.