Concentric Load Acceleration Cycles (CLAC) is one of Exxentric’s methods for eccentric overload using flywheel training on the kBox.


Not an overload setting by itself but a combination of alternating overloaded concentric actions and high eccentric overload and maximal concentric-eccentric actions without overload.

How to do it

On the kBox, do overloaded concentric action followed by an overloaded eccentric phase where you try to reverse the flywheel as fast as possible (you will be pulled down hard!). Go into a maximal concentric contraction and finish with an ordinary eccentric phase down into deep start position and go again with an overloaded concentric action.

Example with biceps curl:

1. Squat/deadlift to start the motion and finish off the concentric (CON) phase with the biceps curl.
2. Reverse flywheel in the eccentric (ECC) phase using only arms (heavy overload).
3. Go directly to maximal biceps curl CON.
4. Second eccentric phase into deep position, ready to squat/deadlift again.

When you can use it

Most upper body drills.

Good for

Dynamic overloaded actions in a fast pace. Great for finishing off a maximal set using CLAC in the last 2-3 reps if you can maintain power with primary muscles. A real finisher. With low inertia very demanding on cardio respiratory system if you go with higher volumes and fast shifts between drills and good for HIT or circuit training sessions.


Really taxing. High demands on the form when fatigue kicks in, as though in our courses.

Further reading

Proceed to learn more about our courses and equipment, or go back to the methods.