Dr Darden,
Have you had the opportunity to try a flywheel trainer? If so, what did you think? If not, I highly recommend you do.
They use negative accentuated reps as a sales argument, though it’s actually the trainees ability to produce significant positive force, that creates the equal negative force (like a yo-yo).
I’m currently experimenting with an Exxentric brand Kbox (a swedish company, nearby located), which provides an unique feel as inertia is the force provided. If you mount heavier flywheels to the device, the positive rep needs significant force to start the flywheel (reminds me a bit of older Nautilus machines), thus the negative equivalent gets similarly heavy. Also, heavier flywheels can provide a rep cadence of 4 sec pos and 4 sec neg. It’s not possible to do any slower functional reps. It is a new stimulus, and 60-90 secs will get your attention. I have noticed that the last part of the negative rep is the hardest (as you need to break the force created in the positive). The device requires some learning, a break in period, to feel comfortable, though I do feel my previous HIT background helped a lot.
The negative aspects may be the price. Flywheel devices are ridicoulously expensive, though I bought a second hand version for half the price (still expensive). Another negative thing is that it’s hard to do chest excercises. Also, you may have a hard time tracking progress (though there is an optional mountable Kmeter device to keep track). I register flywheels/inertia and reps during a 60-90 sec TUT.
I have tested a couple of submaximal full body HIT workouts, supplementing chest with dumbbell flyes or banded pushups. I find this is the best small home gym HIT solution I have tried. The force distributed is to be reckoned with. It’s fantastic that such a small board can produce these (negative) forces.
I understand the flywheel concept but I’ve not used the machines you mentioned. Let us know how your training progresses.
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Would it be fair to describe this as a kind of a ballistic movement, albeit somewhat slower than jumping or plyometrics? You put energy and momentum into the fly wheel, and then used eccentric braking to extract the energy?
I know some physiologists have done research on the use of ballistic movements as a way of reducing the loss of power production with age. The issue with older subjects is safety, and the risk of connective tissue injury. This strikes me as being somewhat safer than some other kinds of ballistic movements.
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Great to have your input here, Al!
I would say it’s ballistic to a certain extent. But it can also be a smooth and controlled movement. It depends on:
A) Resistence (inertia, in practical terms size and number of flywheels), and
B) The tempo you (chose to, or are able to) produce on the positive rep.
There is also a C) How you choose to receive the negative. A matter of adjustment of range of movement, and also whether you move “ahead” of the machine on the negative (which results in a very ballistic reception when the force produced hit you). I’ve also heard of assisted positive reps (where you push yourself up by the arms when doing belt squats for example) which produces an even greater negative force.
I consider this equipment safer than traditional weights, as you are more in control of the forces. Also very practical, as it’s only a board with rope and handles - that can almost replace an entire gym (I can’t believe I said that). But, it’s another stimulus, compared with free weights - Which makes it the perfect companion to a regular weight room.
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I own a K-box. I love it, but my focus is more sports training related for my three boys.
It’s a versatile piece of equipment, relative to the space that it takes up, but it comes with a cost.
The data compared to isotonic training is impressive, related to sports performance.
You can do explosive movements, without nearly the risk of injury compared with traditional Olympic training.
Unfortunately I don’t use it much anymore now that my older two are in S&C programs through the high school and middle school.
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