Low-Impact Resistance & Kinetics in Ellipticals
Elliptical machines are known for low-impact exercise. Behind this advantage is the smooth transfer of kinetic energy within the machine's motion system.
Low-Torque Zone
Cycling exercise devices such as ellipticals or stationary bikes have a Low-Torque Zone, where the exerciser's downward stepping force produces little or no torque to rotate the crank.
This zone occurs whenever the crank passes through its upright or straight-down position, where the force has minimal leverage on the crank.
Our musculoskeletal system is largely designed to overcome gravity. Our legs naturally step downward rather than push forward or backward.
Instead of requiring the exerciser to deliberately push the pedals forward or backward through the low-torque zone, elliptical machines use a flywheel system to carry the drivetrain through this zone. This helps avoid abrupt changes in force and produces smooth, low-impact resistance.
Kinetic Energy Transfer
How a flywheel helps with passing the low-torque zone?
A rotating flywheel stores kinetic energy in the drivetrain when the exerciser is effectively driving the machine. As the crank enters the low-torque zone, the flywheel transfers this stored energy back to the drivetrain, helping the system pass smoothly through the zone. This maintains movement continuity and smooth out jerky resistance.
Why bicycles don't require large flywheels?
The flywheel in a bicycle primarily functions as a pulley.
Although the rotation system (pulleys and wheels) of a bicycle stores some rotational kinetic energy, the bicycle mainly rely on its forward motion to store and transfer linear kinetic energy to help pass the dead zone when pedaling.
Ellipticals are stationary machines and do not produce linear kinetic energy. They rely primarily on the rotational kinetic energy stored in the flywheel and transfered it back to the drivetrain to maintain movement continuity and pass the dead zone.
Our discussion of kinetic energy (KE) in ellipticals usually refers to Rotational Kinetic Energy (KErot)
Conventional Elliptical Machines
Large Flywheel
Conventional elliptical machines are usually designed with a large flywheel.
As the primary component responsible for storing and transferring kinetic energy in the system, the flywheel must either be large enough or rotate fast enough to store sufficient energy for movement continuity and to effectively reduces abrupt force changes encountered in the low-torque zone.
Slow Rotation
A conventional elliptical machine is essentially a plannar four-bar linkage device that directly drives a flywheel. Its flywheel rotates at the same rate as the pedal stroke.
Because the flywheel roates relatively slow, the elliptical machine relies primarily on flywheel size to achieve the kinetic energy storage required for the machine to carry through the low-torque zone.
This is why conventional elliptical machines are typically designed with a large flywheel.
Limited Kinetic Energy Storage
The kinetic energy storage that a conventional elliptical machine can achieve if limited by the flywheel size, because it is not practical to make the flywheel overly large.
Low Resistance Design
Conventional elliptical machines are primarily designed to provide lower resistance due to their limited kinetic energy storage.
Higher resistance design would require higher kinetic energy storage to help smoothly pass through the low-torque zone.
Therefore, conventional elliptical machines are more suited for low-resistance cardio or aerobic exercises.
Introducing the LB007 Vertical Elliptical
The LB007 Vertical Elliptical adopts a different design approach. Instead of relying primarily on a larger, heavier flywheel, it achieves higher kinetic energy storage by increasing
15x Flywheel Velocity & High Kinetic Energy
In the LB007, a two-stage transmission drivetrain is added to the conventional four-bar linkage structure. The transmission increases the flywheel's rotational speed to 15 times the pedal stroke rate, allowing the scaled-down flywheel to achieve substantially higher kinetic energy storage.
Broad Resistance Span
Higher KE storage capability allow LB007 to smoothly pass the crank dead zone at higher resistance force. LB007 is designed to maintain smoothness, continuity and low-impact characteristics on a broad resistance span, from low to high.
Versatile Exercise Framework
Due to its broad resistance span, LB007 is suitable not only for aerobic exercise in low-resistance settings, but also for HIIT and resistance-oriented training in medium and high resistance settings.
Responsiveness & Engagement
The 15× flywheel speed also significantly increases acceleration resistance. When the exerciser increases the pedal stroke rate, additional energy is required to accelerate the high-speed flywheel and the kinetic energy stored in the system.
As a result, the machine responds immediately to changes in pedaling effort. Faster pedaling demands greater power output, while slower pedaling requires less. This responsive relationship between effort and resistance creates a more dynamic, engaging, and natural exercise experience.
| Mode | Resistance | Cadence Duration |
Comparable Exercise |
| Aerobic | L1 - L3 | Fast Long |
Conventional Ellipticals |
| HIIT | L4 - L6 | Moderate Medium |
Stationary Bike or Stepping Machine |
| Strength Training | L7 - L8 | Slow Short |
Climbing Machine |
Vertical Elliptical 5x11TM
The LB007 is designed around a Vertical Elliptical 5x11 pedal motion profile.
The pedal follows a short horizontal stride and relatively large vertical lift. This geometry reduces the dead zone region and works synergistically with the high KE drivetrain to provide smooth and effective exercise across a broad resistance span.
KE Comparison
Conventional Ellipticals vs LB007
The table below compares a typical mid-range commercial elliptical, NordicTrack AirGlide 14i Elliptical with LB007 Vertical Elliptical.
Manufacturers often only publish the flywheel weight but not the size. In fact, the size and shape of flywheel are more important than the weight in calculating the kinetic energy storage.
For AirGlide 14i, the published flywheel weight is 32lb. The diameter is not published, and so it is estimated to be ⌀20" from the approx dimensions measure from product images (Open AI assisted).
For a typical mid-range commercial elliptical, a flywheel of ⌀18" and 25lb is taken as representative in the calculation.
The calculations below use the same engineering method for all three flywheels, assuming rim-weighted spoke-type flywheels operating at one pedal stroke per second.
| Typical Mid-Range Commercial Elliptical | NordicTrack AirGlide 14i | LB007 Vertical Elliptical 5x11TM | |
| Mechanics | Four-bar linkage direct-drive flywheel | Glide Track direct-drive flywheel | Four-bar linkage Two-stage transmission |
| Transmission Ratio | 1:1 No Transmission | 1:1 No Transmission | 1:15 |
| Flywheel Diameter | 18" | Undisclosed Estimated ⌀20" |
⌀9.4" |
| Flywheel Weight | 25 lb | 32 lb | 2.5 kg (5.5 lb) |
| Flywheel Velocity @ 1 Pedal Stroke/sec |
60 RPM | 60 RPM | 900 RPM |
| KErot | 8 Joules | Undisclosed Estimated 13 Joules |
111 Joules |
Summary
Low-impact exercise on an elliptical machine depends on maintaining movement continuity through the dead zone. To achieve this, momentum must be maintained within the machine's motion system.
The flywheel is the primary component responsible for storing and transferring the rotational kinetic energy (KE) needed for passing crank dead zone and maintaining smooth resistance. Conventional ellipticals typically rely on large flywheels because their direct-drive architecture limits flywheel velocity to the pedal stroke rate.
As resistance increases, the kinetic energy required to smoothly pass the dead zone also increases. The practical limits of flywheel size and weight therefore restrict the resistance range of conventional ellipticals.
The LB007 Vertical Elliptical adopts a different approach. Through a two-stage transmission drivetrain, the flywheel rotates approximately 15 times faster than the pedal stroke rate. This Velocity Flywheel architecture enables substantial KE storage with a compact flywheel.
Combined with the Vertical Elliptical 5x11TM Pedal Motion Profile, the LB007 achieves smooth movement continuity across a broad resistance span, supporting aerobic exercise, HIIT, and resistance-oriented training within a compact home-use machine.
Understanding the relationship between dead zones, momentum, kinetic energy, flywheel design, and pedal motion profile provides a useful framework for evaluating the performance characteristics of elliptical machines.