Are low‑drop (4–6 mm) and zero‑drop (0 mm) running shoes detrimental for runners with tight calves, Achilles tendinopathy, recent Achilles injury, plantar fasciitis, or knee/hip pathology?

Low-Drop and Zero-Drop Shoes: Risk Assessment for Runners

Low-drop and zero-drop running shoes are detrimental for runners with tight calves, Achilles tendinopathy, or recent Achilles injury, but may benefit those with patellofemoral pain or knee pathology—the key determinant is whether the runner has adequate calf flexibility and has been gradually transitioned to the lower drop.

Contraindications: When Low/Zero-Drop Shoes Are Harmful

Achilles Tendon Pathology

• Avoid low-drop and zero-drop shoes in runners with tight calves, active Achilles tendinopathy, or recent Achilles injury 1, 2
• Zero-drop shoes increase ankle dorsiflexion demands and shift mechanical load posteriorly to the Achilles-calf complex 3
• The American College of Foot and Ankle Surgeons emphasizes calf-muscle stretching as the cornerstone of plantar fasciitis treatment, indicating that tight calves are a primary risk factor for posterior chain overload 2
• Reduced dorsiflexion range is identified as a biomechanical risk factor for lower extremity stress injuries 1

Plantar Fasciitis

• Exercise caution with zero-drop shoes in active plantar fasciitis, as these shoes eliminate the heel lift that can reduce tension on the plantar fascia 2
• Proper footwear with adequate support (1-2 cm longer than foot, appropriate width at metatarsal-phalangeal joints) is essential and should provide proven offloading effect 2, 1
• Avoid walking barefoot or in minimal footwear during active plantar fasciitis 2

Indications: When Low/Zero-Drop Shoes May Be Beneficial

Patellofemoral Pain and Knee Pathology

• Low-drop and zero-drop shoes reduce patellofemoral joint stress by more than 15% compared to traditional running shoes with 10-15mm drops 4, 5
• Negative heel shoes (-11mm drop) decrease peak patellofemoral joint stress, knee extension moment, and quadriceps force in runners with patellofemoral pain 5
• The mechanism involves reduced knee flexion angle and decreased knee extension moment during stance phase 4
• Zero-drop shoes promote forefoot strike patterns, which redistribute loading away from the knee 3, 6

Hip Pathology

• Increased peak hip adduction angle is a risk factor for lower extremity injuries 1
• Zero-drop shoes may alter hip biomechanics by changing strike pattern, though direct evidence for hip pathology is limited 3, 6

Critical Transition Protocol

Runner Experience Level Matters

• Regular runners (≥6 months of weekly practice) have 67% higher injury risk when transitioning to low-drop shoes compared to traditional shoes 7
• Occasional runners (<6 months of weekly practice) have 52% lower injury risk with low-drop shoes 7
• This paradox suggests that habitual movement patterns in experienced runners create injury risk during acute transitions 7

Gradual Transition Requirements

• Forefoot strike gait retraining is recommended before transitioning to zero-drop or negative-drop shoes 6
• After 8-week intervention with zero-drop shoes, runners demonstrate increased foot strike index (more forefoot striking) and altered joint work distribution 3
• Immediate effects include increased vertical instantaneous loading rate (31.8 BW/s higher) when acutely switching to -8mm drop shoes 6

Biomechanical Considerations

Calf and Achilles Loading

• Zero-drop shoes increase negative work at the ankle joint, indicating greater eccentric loading of the calf-Achilles complex 3
• Calf strength and flexibility must be adequate before transition 1, 2
• Address lower extremity biomechanics including calf stretching and strengthening prior to footwear changes 1

Metatarsophalangeal Joint Adaptation

• Zero-drop shoes increase metatarsophalangeal joint range of motion in the sagittal plane, potentially improving energy storage and return 3, 6
• However, metatarsophalangeal joint negative work decreases after adaptation period 3

Clinical Decision Algorithm

Step 1: Assess Contraindications

• Active Achilles tendinopathy or recent injury → Do not use low/zero-drop shoes 1, 2
• Tight calves with limited dorsiflexion → Do not use until flexibility improves 1, 2
• Active plantar fasciitis → Use traditional therapeutic footwear with proven offloading 2, 1

Step 2: Identify Potential Benefits

• Patellofemoral pain → Consider low/zero-drop shoes with gradual transition 4, 5
• Knee pathology with increased patellofemoral stress → May benefit from reduced drop 4, 5

Step 3: Evaluate Runner Experience

• Regular runner (≥6 months weekly) → Higher injury risk during transition; requires extended adaptation period 7
• Occasional runner (<6 months weekly) → Lower injury risk; may tolerate transition better 7

Step 4: Implement Transition Protocol

• Initiate gait retraining toward forefoot strike pattern before footwear change 6
• Begin with 5-6mm drop shoes before progressing to zero-drop 7
• Allow minimum 8-week adaptation period with gradual volume increase 3
• Monitor for increased calf soreness, Achilles pain, or metatarsal stress symptoms 3, 6

Common Pitfalls

• Acute transition without gait retraining leads to dramatically increased loading rates and injury risk 6
• Ignoring baseline calf flexibility results in Achilles overload 1, 2
• Assuming all runners benefit equally when regular runners face higher injury risk during transition 7
• Using zero-drop shoes for plantar fasciitis without addressing the underlying need for offloading and support 2