Is a 22mm Heel Drop Too High?
Yes, a 22mm heel-to-toe drop is excessively high and should be avoided, particularly for runners who spend long periods on their feet, as it significantly increases patellofemoral joint stress and may elevate injury risk.
Evidence-Based Concerns with High Heel Drops
Patellofemoral Joint Stress
- Running shoes with heel drops ≥10mm increase peak patellofemoral joint stress by more than 15% compared to zero-drop shoes 1
- This increased stress occurs primarily due to elevated knee extension moments when running in shoes with drops >5mm 1
- The knee flexion angle significantly increases with heel drops of 15mm, 10mm, and 5mm, contributing to greater joint loading 1
Biomechanical Alterations
- Higher heel drops (8mm standard shoes vs. -8mm minimalist) result in decreased metatarsophalangeal joint range of motion, which may reduce the foot's natural energy storage and return capacity 2
- Shoes with positive heel drops promote rearfoot strike patterns, whereas lower or negative drops encourage midfoot-to-forefoot striking 2, 3
- The strike index increases significantly when transitioning to lower drop shoes, indicating a shift toward more anterior foot contact 3
Injury Risk Considerations
Population-Specific Effects
- For regular runners (≥6 months of weekly practice): Low-drop shoes are associated with a 67% higher injury risk (HR 1.67,95% CI 1.07-2.62) compared to 10mm drop shoes 4
- For occasional runners (<6 months of weekly practice): Low-drop shoes reduce injury risk by 52% (HR 0.48,95% CI 0.23-0.98) 4
- Overall injury risk shows no significant difference between 10mm, 6mm, and 0mm drops when not stratified by running regularity 4
Muscle Force Implications
- Negative heel drop shoes (-8mm) significantly increase forces in the lateral gastrocnemius, Achilles tendon, and flexor hallucis longus muscles, potentially elevating risk for Achilles tendonitis and ankle flexor injuries 5
- Conversely, these shoes decrease forces in the vastus medialis, vastus lateralis, and extensor digitorum longus muscles 5
Clinical Recommendation
For a runner spending long periods on their feet, a 22mm heel drop is not supported by any evidence and exceeds all studied parameters. The highest heel drop systematically studied is 15mm, which already demonstrates significant biomechanical disadvantages 1.
Practical Guidance
- Optimal range: Consider shoes with 6-10mm heel drop for regular runners to balance injury risk and biomechanical efficiency 4
- Transition protocol: If currently using high-drop shoes, gradual transition over 8+ weeks is essential, as immediate changes to lower drops alter lower extremity joint work distribution 3
- Individual factors: Regular runners (your case) should avoid abrupt transitions to very low or zero-drop shoes due to increased injury risk 4
Key Caveats
- The relationship between heel drop and injury is modified by running regularity—what works for occasional runners may harm regular runners 4
- Vertical instantaneous loading rates increase by approximately 32 BW/s when transitioning from 8mm to -8mm drop shoes 2
- Forefoot strike gait retraining is recommended before transitioning to minimalist or negative-drop footwear 2
Bottom line: A 22mm heel drop has no evidence base and likely compounds the patellofemoral stress problems documented with 15mm drops. Choose footwear in the 6-10mm range for optimal biomechanical function and injury prevention.