Advantages
Eccentric Training and Overload
One of the most important advantages of flywheel training on the kBox is its ability to provide eccentrically overloaded training in a safe, practical and efficient way.
Fundamentals
Your muscles are stronger in the lengthening (eccentric), the phase of its motion, as compared to the shortening (concentric), phase.
Training the eccentric phase has strong scientific support, the most important being increasing total strength and hypertrophy. As many injuries occur during eccentric contraction, eccentric training can also greatly reduce the risk of injury for elite athletes as well as rehabilitation clients. Eccentric training is also shown to transform muscle into a faster phenotype.
In regular strength training with weights, the load in the eccentric phase is limited to how much the weaker concentric phase can lift. As a result, the eccentric phase is rarely loaded to its maximum, and the training loses efficiency.
Training with focus on the eccentric phase is called eccentric or negative training.
Eccentric Overload
Eccentric overload is when the eccentric force is larger than the maximal concentric force.
To reach your maximal force in the eccentric phase, you need to apply some method to get eccentric overload.
In traditional strength training with weights, achieving eccentric overload is challenging from both a practical and a safety point of view. The traditionally applied methods include:
- Help from training partners with lifting beyond your max in the concentric phase, as well as controlling yourmovement in the eccentric phase. These methods are often time-consuming and have a high risk of injury.
- Using certain weights stack machines, for example, leg extension by using both legs up and only one leg down, which is not a very functional movement.
- “Cheating” using auxiliary muscle in the concentric phase, but you often get less efficiency in the concentric phase and also increases the risk of injury.
The Flywheel Advantage
With flywheel training, eccentric training and heavy eccentric overload have never been easier or safer.
Using the kBox you can use our methods to perform eccentric training with overload without help and also without the risks associated with traditional methods.
If you decelerate the flywheel in a shorter time than the acceleration phase, you will produce a higher eccentric force. You can also produce force in the concentric phase with auxiliary muscle and only use certain muscles in the eccentric phase to overload them. Read more.
With the addition of the kMeter wireless feedback system, you can easily measure the eccentric power and overload.
Eccentric training is getting safer and less practically challenging as flywheel training gains momentum across the globe.
Further Reading
- Carl Valle Busting Myths About Eccentric Training
- Is Eccentric Overload on the kBox3 Safe?
- How the CLAC Method Will Boost Your Eccentric Training
- kBox Usage Can Make Swimmers Start 35% Faster
- Afraid of Muscle Soreness?
- Eccentric Overload Gives Faster Muscles
Proceed to learn more about our courses and equipment, or go back to the physiological advantages of flywheel training.
Full video available here
kBox4 Active
Kickstart your Flywheel Training with our entry-level kBox model. The perfect device for strength training, rehabilitation, injury prevention, and training in general. Available with our free Flywheel Training app to design all your kBox workouts.

- Ideal for...
- • Home Gyms
- • Personal Trainers
- • Group Classes
kBox4 Lite
Broader range of resistance provided by the lightest kBox model, practical to pack and bring with you on the move. Its built-in kMeter feedback system allows you to monitor your progress in real-time.

- Ideal for...
- • Travelling Athletes
- • Fitness Studios
- • Physiotherapy Rooms
kBox4 Pro
The premium and best-selling kBox model with the largest performance area. Made for intense workouts and serious strength building exercises. Its built-in kMeter feedback system allows you to monitor your progress in real-time.

- Ideal for...
- • Professional Teams
- • Performance Centers
- • Physiotherapy Clinics
kPulley2
The kPulley unlocks a variety of horizontal movements, creating limitless training possibilities especially when combined with the kBox. Its built-in kMeter feedback system allows you to monitor your progress in real-time.

- Ideal for...
- • Professional Teams
- • Performance Centers
- • Physiotherapy Clinics
kPulley Go
Kickstart or enhance your Flywheel Training setup with one of our entry-level models. Its compact size and design provides you with freedom in your training, while also maintaining a great capacity for loading & variable resistance.

- Ideal for...
- • Home Gyms
- • Group Classes
- • Physiotherapy Rooms
SingleExx
These uniquely mobile machines allow you to incorporate leg extension & flexion movements into your training like never before with variable & unlimited resistance. Progress can be monitored in real-time and beyond through the Exxentric app.

- Ideal for...
- • Professional Teams
- • Health Clubs
- • Physiotherapy Clinics
OPEN FACILITIES
Curious to put Flywheel Training to the Test?
Experience the true effectiveness and potential of the Exxentric kBox, kPulley, LegExx or LegFlexx. Click here to find facilities that offer Exxentric Flywheel Training sessions in your region: