Table 2.

Incidence rate of knee and hip replacement by levels of physical activity.

ActivityIncidence Rate*, Knee ReplacementIncidence Rate*, Hip ReplacementPerson-yrs
Total physical activity level
  None (0)2.52.342,000
  Low (> 0–3)2.82.038,000
  Moderate (> 3–4)2.92.548,000
  High (> 4)3.12.960,000
Vigorous activity**
  None at all2.92.5150,000
  1–2 times/week3.02.522,000
  ≥ 3 times/week2.22.619,000
Less vigorous activity**†
  None at all2.72.296,000
  1–2 times/week3.22.826,000
  ≥ 3 times/week3.63.025,000
Walking**†
  None at all2.92.563,000
  1–2 times/week2.71.928,000
  ≥ 3 times/week3.22.756,000

  • ↵* Incidence rate of primary knee or hip replacement (per 1000 person-years) within each physical activity category.

  • ↵** Weekly frequency of physical activity undertaken for at least 20 minutes.

  • ↵† Excluding those reporting vigorous activity.