Running and Knee Arthritis: Separating Fact from Fear
As a Physiotherapist, one of the most common concerns I hear from runners is: "Will running ruin my knees?" This fear has persisted for decades, causing many people to avoid this incredibly beneficial form of exercise. Interesting new research may help us understand this a little better.
The Important Research: Running Volume and Knee Osteoarthritis
A comprehensive 2023 systematic review and meta-analysis published in Physical Therapy in Sport sought to determine if weekly running volume is associated with knee osteoarthritis. This rigorous study analysed data from 9 observational studies involving 12,273 participants (1,272 runners), making it one of the most comprehensive analyses on this topic to date.
What the Researchers Did:
- Analysed 9 studies with 12,273 total participants
- Compared runners to non-runners
- Categorised running volume into three levels: 8-32.1 km/week, 32.2-48 km/week, and >48 km/week
- Measured knee osteoarthritis prevalence using both radiological imaging and self-reported diagnoses
- Used rigorous statistical methods, including random effects models
The Important Findings:
Contrary to popular belief, the analysis found no significant difference in the prevalence of knee osteoarthritis between runners and non-runners across all volume categories.
| Running Volume (per week) | Odds Ratio for Knee OA | Statistical Significance |
|---|---|---|
| 8-32.1 km (Recreational) | OR = 1.17 | Not significant |
| 32.2-48 km (Moderate) | OR = 1.04 | Not significant |
| >48 km (High Volume) | OR = 0.62 | Not significant |
Even at the highest running volumes (>48 km per week), researchers found a trend toward lower osteoarthritis prevalence, though this wasn't statistically significant.
Context from Previous Research
These findings align with earlier research that distinguished between recreational and competitive running. A 2017 meta-analysis found that recreational runners actually had lower rates of hip and knee osteoarthritis (3.5%) compared to both competitive runners (13.3%) and sedentary non-runners (10.2%). This suggests a U-shaped relationship where moderate running is protective, while either sedentary behaviour or extreme competitive running may increase risk.
Important Limitations and Generalizability
Considerations When Interpreting These Results:
- Study Quality: Most included studies had a high or very high risk of bias
- Observational Nature: These studies show association rather than causation
- Population Gaps: The research primarily focused on general running populations rather than those with pre-existing conditions
- Need for More Research: The authors emphasised the need for larger-scale, high-quality prospective studies
The Physiotherapist's Perspective: Why Running Exposes Hidden Issues
While the evidence may suggest running itself doesn't cause arthritis, I consistently find that running is very good at exposing underlying mechanical issues that may have otherwise gone unnoticed. Here's why:
The Repetition Magnifier Effect
Running involves approximately 1,500-2,000 steps per mile, each with impact forces of 2-3 times body weight. This repetition magnifies subtle biomechanical imperfections that daily activities might not reveal. What feels like minor discomfort during walking can become significant pain during running due to this cumulative effect.
Common Hidden Issues Running Reveals
- Muscle Weakness: Particularly gluteal and core muscle weakness, which can lead to femoral internal rotation and increased knee valgus stress
- Joint Mobility Restrictions: Ankle dorsiflexion, quadriceps, and hip rotational restrictions can force the leg to "work around" these limitations, ultimately altering how we load our legs.
- Proprioceptive Deficits: Poor balance and coordination that become apparent with the dynamic demands of running
- Previous Injury Compensation: Old injuries that created movement patterns that running stresses
Key Takeaway for Runners:
Running is unlikely to create knee problems, as running is normal. But it can expose them. The issue typically isn't the running itself, but rather the underlying biomechanical issues that the repetitive, loaded nature of running exposes.
Practical Recommendations for Healthy Running
For New Runners:
- Start with a walk-run program and progress gradually (no more than 10% volume increase per week)
- Invest in appropriate footwear based on your foot type and gait pattern
- Incorporate strength training 2-3 times per week, focusing on hips, glutes, and core
- Listen to your body - distinguish between normal muscle soreness and joint pain
For Experienced Runners:
- Pay attention to persistent pains that don't resolve with rest
- Consider a running gait analysis to identify efficiency issues
- Vary your training surfaces and include recovery weeks in your program
- Address minor issues before they become significant problems
When to Seek Professional Help:
- Pain that persists beyond 48 hours after running
- Pain that changes your running form
- Swelling in any joint
- Pain that intensifies during a run rather than easing up
Final Thoughts from a Physiotherapy Perspective:
The evidence is becoming clearer: recreational running may not be associated with increased risk of knee osteoarthritis. In fact, it may be protective compared to a sedentary lifestyle. The running community can take confidence from these findings while understanding that running serves as an excellent diagnostic tool for identifying underlying biomechanical issues that deserve attention.
Rather than fearing running as destructive to joints, we should view it as an activity that provides valuable feedback about our movement system. By addressing the issues running reveals, we can not only run more comfortably but also move better in all aspects of life.
Need Personalised Guidance?
If you'd like help trying to uncover the underlying cause of your pain or dysfunction, consider booking an online Telehealth consultation with Grant here!
