The Science of Stride: What We Learn from Video Gait Analysis at Different Bodyweights

At Princeton Sports and Family Medicine, P.C. in Lawrenceville, New Jersey, we use video gait analysis on the AlterG Anti-Gravity Treadmill to reveal how patients move—not just at full bodyweight, but across a spectrum of unweighting levels. This approach provides powerful insight into biomechanics, compensation patterns, and recovery potential.

Understanding how gait changes under different loads helps therapists customize rehab, reduce reinjury risk, and accelerate safe return to activity.

Why Gait Looks Different at 100%, 80%, and 60% Bodyweight

Pain, weakness, or fear of movement often distorts how patients walk or run. When they move at full bodyweight (100%), their mechanics may include:

• Shorter stride length

• Favoring one side

• Limited joint mobility

• Decreased push-off

• Guarded posture

As we reduce bodyweight via the AlterG (e.g., to 80% or 60%), these patterns often begin to normalize. Patients move more freely, symmetrically, and confidently—unmasking their true functional capacity.

The Role of Video Gait Analysis

By pairing the AlterG with video capture and playback, our therapists can precisely analyze gait at each unweighting level. We assess:

• Step length and cadence symmetry

• Pelvic and trunk stability

• Heel strike vs. midfoot strike

• Knee alignment and tracking

• Push-off and propulsion from the toes

We don’t rely on guesswork. We show patients exactly how their movement evolves with each incremental change in load—giving them clear, visual proof of progress.

How Therapists Use This Information

Understanding gait at different bodyweights allows clinicians to:

• Identify the ideal starting point for rehab walking or running
• Tailor loading progression based on observed mechanics
• Correct faulty movement patterns early, before they become habits
• Bridge the gap between unweighted and full-weight running
• Build strength and motor control in a safe, pain-free zone

For example:

• A post-ACL reconstruction patient may move symmetrically at 70% bodyweight, but show quad weakness and compensation at 85%. That tells us where to focus strength work before progressing.

• A chronic hip pain patient might exhibit a limp at full bodyweight but normalize their gait at 80%. We can then retrain proper mechanics at that level before gradually increasing load.

Real Results. Personalized Recovery.

The combination of variable loading and objective video feedback allows us to progress patients more precisely, more confidently, and more safely than traditional rehab alone.

Whether you’re returning from surgery, recovering from an injury, or aiming to prevent future problems, the science of stride can guide the way.

Interested in seeing how your gait changes with unweighting?
Contact Princeton Sports and Family Medicine, P.C. to schedule your AlterG gait analysis. Book online or call us today.

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.