Return to Run: A Step-by-Step Protocol Using the AlterG After Injury or Surgery

Returning to running after injury or surgery requires a careful balance of stress and support. Progress too quickly, and you risk reinjury. Wait too long, and you lose fitness, motivation, and confidence. At  Princeton Sports and Family Medicine, P.C. in Lawrenceville, New Jersey, we use the AlterG Anti-Gravity Treadmill to guide runners safely and efficiently through the Return-to-Run (RTR) process.

Using bodyweight-supported running, we help patients recovering from stress fractures, tendon injuries, and post-operative procedures rebuild capacity while protecting healing tissues.

Why the AlterG Works for Return-to-Run

The AlterG allows for precise offloading of bodyweight (as low as 20%) using differential air pressure. This minimizes impact forces on healing tissues while maintaining the neuromuscular patterns and aerobic conditioning of real running.

Paired with video gait analysis and clinical supervision, the AlterG creates the ideal platform to reintroduce load gradually, objectively, and safely.

AlterG Return-to-Run Protocol: Phased Progression

This structured protocol is based on percentage of bodyweight, time/mileage, and symptom response. Progression is individualized, but general benchmarks are as follows:

Phase 1: Initiation Phase (60–70% BW)

Goal: Pain-free movement and normalized gait under reduced load

• Criteria to start: No pain at rest, no limping while walking, cleared by physician

• Bodyweight: 60–70%

• Speed: Walk–jog transitions or light running pace

• Duration: 10–20 minutes, every other day

• Key Focus: Monitor for symptoms during and after session (pain <2/10)

▶️ Progress when: 3 sessions completed with no pain during or next day

Phase 2: Adaptation Phase (70–85% BW)

Goal: Build time-on-feet and re-establish running rhythm

• Bodyweight: Increase in 5–10% increments every 2–3 sessions

• Duration: 20–30 minutes

• Intensity: Easy/moderate pace (Zone 2 effort)

• Frequency: 3x/week

Author

Peter Wenger, MD Peter C. Wenger, MD, is an orthopedic and non-operative sports injury specialist at Princeton Sports and Family Medicine, P.C., in Lawrenceville, New Jersey. He is board certified in both family medicine and sports medicine. Dr. Wenger brings a unique approach to sports medicine care with his comprehensive understanding of family medicine, sports medicine, and surgery. As a multisport athlete himself, he understands a patient’s desire to safely return to their sport.