Strength training equipment 2.0: Exentrix


The use of equipment in strength training is not new. It started with simple implements like dumbbells,  medicine balls, cattlebells and barbells to equipment like  benches, leg extension, squat rack and machines, leg press etc. Followed by  special apparatus were resistance is delivered by levers, cams, springs, cables, rubber bands,  water, air or oil pressure. Some of those were mechanically controlled, others by software. 

While almost all of these machines have contributed to our strength training one time or another, most of them had a limited use due to:
  •  limitation in applying the optimal resistance e.g. the balance between concentric and eccentric load
  •  limitation of possible functional uses, e.g. one exercise only (isolated muscle groups-e.g. knee extension)
  • lack of ability to use it in a flexible, open way, only one form of resistance  possible e.g. only isokinetic of only isotonic
  • limitation in efficiency in adjusting the resistance e.g. stop the exercise to put more weights on the barbell

But here is the good news: Strength training equipment 2.0 is ready and in use!

The machine I am using right now is called Exentrix. It as software controlled resistance machine that finally allows me to do what I want it to do, like:
  • using it in combination with existing free equipment like dumbbell or barbell
  • using it in combination with existing resistance machines like leg extension or lat pulley
  • using it for functional, more dimensional exercises through a pulley system 
 Rugby conditioning coach testing the Exentrix’ possibiliies
 Now I also can apply very different resistance modes in an exercise that I choose, like:

1. isotonic, resistance stays the same (like with barbell or dumbbell)
2. isokinetic, velocity stays the same throughout the range of motion (as in Cybex) 

3.isoinertial, inertia stays the same as with  YoYo , flywheel or Versapulley  systems)

4. “aerobic”, resistance based on the fan-based rowing machines e.g. Concept 2

5. rubberband, resistance like pulling a rubber tube or Theraband

More me, this is already  a great leap forward to me, but it does not end there.

With the Exentrix I now can set the concentric and eccentric resistance within a movement separate from each other! For example in isokinetic: I can set the concentric velocity at 30 cm/sec, but eccentrically at 100 cm/sec or I can set the concentric velocity at 80 cm/sec and eccentrically at 40 cm/sec. 

All of this on the fly, that means while the athlete is executing his /her movement!

And also adjust the transition from concentric to eccentric from a very sharp to a very smooth transition.

And still the box isn’t empty: the Exentrix allows me to add: 

1.   superimposed vibration to a movement and I can determine the amplitude and frequency

2.   random perturbation  (a sudden, unexpected pull) to shock the nervous system.

These last two options significantly increase muscle fibre recruitment!

And last but not least the Exentrixhas an almost unlimited set of options which enables you to combine it with other inputs or outputs like EMG, EMS, electronic timing, jump mat, force transducer or platform, acoustic stimuli, etc.

The Exentrix can also be used in overspeed training by pulling a kayak or a sprinter.

The use of it is mainly limited by my own creativity.

For a short movie about the Exentrix: http://vimeo.com/50756145

For more information about the Exentrix: contact me at: info@vortx.nl 

About Henk Kraaijenhof

My name is Henk Kraaijenhof and I started this blog as a random collection of concepts, ideas, stories and events that are important or interesting to me in my work as an international performance consultant in a wide range of fields, and sometimes outside of my work. I will try to post a new entry every 3-4 days. Feel free to comment if you like.
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