The force in a flywheel training exercise depends on a combination of the intensity you work with and the selected inertia. With a higher inertia, the motion will be slower and more controlled, and your muscle will be able to produce a higher force. With a lower inertia, the motion will be faster which also puts higher demands on skill, balance and technique.
The inertia resulting from the size and number of flywheels you select impacts the training adaption you get. Together with your workout intensity, the inertia chosen decides your Flywheel Workout Zone, which can include strength training, power training, eccentric overload and warming-up.
The kBox, kPulley and LegExx can be equipped with two or four flywheels simultaneously depending on the device model. Additionally the Advanced Flywheel Knob can help to boost that capacity by two flywheels of a compatible size.
The flywheels are available in five different sizes:
- Extra Large: 0.070 kgm² (only compatible with the kBox4 Pro, LegExx, LegFlexx and all kPulley devices)
- Large: 0.050 kgm²
- Medium: 0.025 kgm²
- Small: 0.010 kgm²
- Extra Small: 0.005 kgm²
The medium and light flywheels can be used both on their own for high-speed exercises and weaker individuals (such as for rehabilitation), but they can also be used to fine-tune the inertia at higher loads. The Single-Turn Buckle can help you get the most effectiveness out of an Extra Small flywheel.