This varies by individual, goal, and — in clinical settings — by treatment plan. Support level is typically adjustable and set based on the person's current needs rather than a fixed universal amount.
How Does Body Weight Support Work?
Train Without Limits
Body weight support works by mechanically offloading a portion of a person's weight through a harness connected to a lift point, so the body carries less load with every step while still moving through its own natural walking or running pattern. Here's exactly how that works, step by step.
The Basic Mechanism: Offloading a Percentage of Body Weight
At its core, body weight support works through a simple physical relationship: a harness worn by the user connects to a lift system, and that system carries a set portion of the user's total body weight. The remaining weight is still carried by the user's own legs and body — they're still doing the work of walking or running, just under reduced load.
What "Percentage of Body Weight Supported" Actually Means
Support is typically expressed as a percentage. If a system is offloading 20% of someone's body weight, that means roughly 80% of their weight is still being carried through their legs with each stride — the load is reduced, not eliminated. This is an important distinction: body weight support isn't about removing effort, it's about reducing the physical stress of that effort.
The right percentage depends entirely on the individual and the goal — a higher percentage might be appropriate for someone in early-stage rehab or returning to running for the first time after injury, while an experienced athlete managing training volume might use a much lower percentage, or adjust it session to session.
How Weight Is Physically Offloaded
The Harness and Lift-Point System
In a frame-based system like LightSpeed Lift, the user wears a harness that connects to an overhead or upright lift point on the frame. That connection is what carries the offloaded weight. The treadmill itself (or the ground, in off-treadmill use) still handles speed and surface — the harness system's only job is managing how much of the user's weight reaches the ground through their legs.
Why Lift Point Location Changes the Outcome
Where the harness connects to the body matters mechanically, not just for comfort. A lift point at the torso or chest pulls upward on the upper body, which can restrict rib cage expansion (affecting breathing) and limit natural arm swing and trunk rotation. A lift point at the hips — closer to the body's actual center of mass — offloads weight without pulling on the torso, which is why hip-based systems tend to preserve a more natural stride, arm swing, and breathing pattern than torso- or chest-based harnesses.
Adjusting Support During Training
Starting Point: More Support, Less Load
Sessions typically begin with a support level appropriate to the person's current tolerance — higher support (more weight offloaded) for someone early in a return-to-running program, gait retraining process, or simply someone who needs significantly reduced load to move comfortably.
Progressing: Reducing Support Over Time
As strength, tolerance, or confidence improves, support is typically reduced in increments — allowing the body to carry progressively more of its own weight until, eventually, full unsupported movement is reintroduced. In clinical settings, this progression is directed by a physical therapist or clinician as part of a broader treatment plan; in athletic training, it's often managed by a coach or trainer based on training goals.
What Happens to Movement When Load Is Reduced
Impact and Ground Reaction Force
Every step involves a landing force — the impact between the body and the ground. Reducing body weight proportionally reduces that ground reaction force, which is the primary mechanism behind why body weight support is associated with lower joint and connective-tissue stress during movement.
Gait Pattern and Natural Mechanics
A well-designed body weight support system aims to reduce that force without meaningfully changing how the person moves. This is where support-point location becomes practically important again: a system that distorts stride length, arm swing, or trunk rotation to achieve unweighting is working against one of the main reasons body weight support is used in the first place — particularly in rehab, where reinforcing normal movement patterns is often the clinical goal.
What a Body Weight Support Session Looks Like
Step-by-Step Walkthrough
- Harness fitting — the user puts on the harness, adjusted for a secure, comfortable fit at the appropriate support point (hips, for LightSpeed Lift systems).
- Connection to the frame — the harness connects to the lift point on the system.
- Support level set — the amount of body weight to be offloaded is set, based on the individual's needs, goals, or clinical plan.
- Movement begins — the user walks or runs (on a treadmill or, for some systems, during off-treadmill functional exercise), with the system carrying the set percentage of their weight throughout.
- Real-time observation and adjustment — because LightSpeed Lift's frame is open and transparent, a coach, trainer, or clinician can watch movement quality throughout and adjust support level as needed.
- Progression over time — across sessions, support level is typically adjusted downward as the person's tolerance and capacity increase.
The LightSpeed Lift Mechanism: Lift From the Hip
LightSpeed Lift's patented Lift From the Hip technology applies this entire mechanism — harness, lift point, adjustable support — specifically at the hips rather than the torso. Because the hips are the body's center of mass and the anchor point for gait mechanics, offloading weight from that location allows the trunk, arms, and legs to move through their full natural range in all three planes of motion, while the transparent frame design keeps movement fully visible for coaching or clinical observation throughout the session.
Frequently Asked Questions
It can, depending on the system. A poorly designed system can distort gait by restricting the torso or limiting arm swing. A well-designed system, particularly one that supports from the hips, aims to reduce load while preserving natural movement patterns as closely as possible.
Yes, in most systems, including LightSpeed Lift's. Support level can typically be adjusted as needed based on how the session is going.
Not necessarily — you're still actively walking or running and doing the work of moving your body; the difference is the physical stress that movement places on joints and tissue, not the exercise itself. The overall training or rehabilitation value depends on the full program design, not the support percentage alone.
A standard treadmill controls speed and incline only. Body weight support adds a third, independently adjustable variable — how much of the user's own weight they're carrying — which a standard treadmill can't do.
In clinical/rehab contexts, this is typically directed by a physical therapist or physician as part of a treatment plan. In athletic or general fitness use, it's often set by the individual, a coach, or a trainer based on training goals.
Find the Right Support for Your Next Step
Now that you understand how body weight support works, explore how LightSpeed Lift can fit your training or recovery goals. Discover the systems or talk with our team about your needs.