What does “Concentric phase” and “Eccentric phase” mean? :

The Concentric phase is when the muscle shortens, or contracts and the Eccentric phase is when the muscle lengthens or extends. When lifting traditional weights mostly concentric loading occurs and the eccentric phase is hard to load manually. Flywheel training adds this overlooked
component, allowing you to strengthen your muscles in both directions with one
rep.

By adding the Eccentric phase to your workouts, you can increase muscle strength more effectively than concentric exercises. This is because when muscles lengthen, fibers in the muscle split more than they do during concentric exercise. As more fibers split, the body works to rebuild them,
resulting in bigger muscles.

Using quick change flywheels you can easily change up the resistance for your targeted strength goals. you can have fewer slow, high resistance reps, or rapid lower resistance reps. These rapid movements are great for burnout reps, allowing you to safely go until you cannot muster one more rep.

No addon cables necessary. All our products come with a generous amount of strap, allowing for movements a great distance away from the source of resistance. This also allows for a variety of force vectors for unique muscle loading applications. The swiveling nature of our vertical post adapters allow for lateral moments mid rep.

You can also remove the flywheel and use the machine for isometric strengthening. Just adjust the strap the desired height and pull as hard as you can, The machine can take this load no problem!

Because the force involved is the kinetic energy of the flywheel, there is no risk of the inherent potential energy associated with free weights. You do not have to worry about dropping weights or overexerting yourself, the only resistance provided is that which you generate yourself during the rep.

Flywheels are an excellent choice for rehabilitation after an injury, and are also very safe for younger athletes.

With the use of stackable flywheels, our machines can handle up to 900 lbs of resistance... If you can generate it.... The capacity of the equipment is limited only by the strap materials tensile strength.

The footprint of Kratos products is quite small compared to the equivalent number of machines and free weights required for the same workouts. Check out our movement library for examples.

Inertia is a linear mass attribute that describes how well an item opposes a change in movement. The moment of inertia of a disc along an axis perpendicular to it and passing through its centre equals ½ * M * R^2, where M is the mass of the disc and R is the radius of the disc.

To put it simply, the harder you pull the faster you accelerate the wheel, wheels with more inertia (larger diameter and or more mass) take more force from you to accelerate.

The Inertia of the flywheel is what creates the resistance against the user of the Quest line of products. Flywheels are completely interchangeable between product models. Flywheels are sold in a variety of sizes to accommodate different resistance ranges. Flywheels can be combined to allow more resistance options, or to increase resistance beyond the use of a singe XL wheel.

Use the top range force equivalence for each flywheel below as a reference when selecting flywheels.

XS (15 lbs), Inertia .0038 KG*m^2

S (30 lbs) , Inertia .0075 KG*m^2

M (60 lbs), Inertia .0149 KG*m^2

L (120 lbs), Inertia .0297 KG*m^2

XL (250 lbs), Inertia .0616 KG*m^2

Actual resistance is created by the user and will be variable based on the velocity of your movements. However these values can be used as a guide to help select the range of flywheels necessary for your strengthening goals. When adding multiple plates you can add the pounds equivalents together to get an idea of how much resistance will be needed to accelerate the stack at about 1.5 m/s.

Most Users will not need more that a XL and a L wheel, this combo is about 370 Lbs of resistance. Multiple XL wheels require a very large amount of force to accelerate at a normal movement speed.

All Kratos flywheel machines are CNC machined in the USA. We offer a 1 year comprehensive warranty on our machines including all the mechanical pieces and the strap.

With enough use components such as the strap and the pulley shives will need to be replaced at some point. We stock replacement parts that are available on our website for these components, and will provide them for free should they wear out in the first year of use. The bearings are accessible on most models and can be lubricated with Slick 50, or your choice of bearing lubricant should they need it. These machines are mechanically sound and should last for many years.

Our products are designed to work with squat racks with 2" X 3" or 3" X 3" posts and with 5/8" or 1" holes. Squat racks with the same sized holes running the full length of the post are preferred. If you have further questions about compatibility with your squat rack please ask.

Squat racks should be bolted down or weighed in a way to allow them to be pulled against without lifting.