Handle Bio-mechanics

[Slidewinder]

Various discussions and comments regarding handle design have appeared in this forum. I have owned a Model B, and now own a Model D. I was dissatisfied with the supplied handle on both models. I was convinced that even the Model D's new "ergonomic" handle forced the user to adopt an arm movement that was bio-mechanically flawed. Angulation of the wrist joint at the completion of the stroke, I reasoned, could not be good. Reports of repetitive stress injuries suffered by high frequency users of the machine, confirmed the soundness of my view.

I thought there might be a simple mechanical solution to this problem. If the solution also resulted in an improved replication of rowing, so much the better. I worked on this problem for a year and a half. The result of my efforts is demonstrated in this video (search "The Canadian Slidewinder" on YouTube):

As can be seen, the final handle design also enables certain non-rowing stroke geometries. Possibly these are of limited interest to rowers, but they are nevertheless completely viable exercises which engage other muscle groups, adding variety to the exercise program and broadening the appeal of the machine. Bio-mechanical integrity is maintained regardless of the stroke geometry utilized. Viewers and I have posted a few comments under the video which you may read.

Another issue which has been addressed in this forum, is footstrap design. The video also shows my solution to the problem of footstraps.

[johnlvs2run]

Thanks for sharing your design. I am very impressed with the quality of your work.

Here is my simple rope design from a few years ago, that I enjoy using much more than the regular C2 handle.
I like using the rope because it has a much better feel for the motion, and completely eliminates vibration from the handle. I hooked my thumbs and fingers around the ends of the handles in the 1st variation.

[Tinus]

I like your designs/inventions and also the skate machine. I have a remark for both.

- The skate machine. Would it be possible to adjust the machine such that the the movement of the legs is less forwar backwards but also slightly more sideways. In such way it would be a better simulation of the skating movement.

- The rowing machine handle. Are you planning on building your own machine or is this handle created as an add-on for people who already have a concept machine? If I, and many others, row on such a machine than there is only little space left between the cage and the handle when the body is at catch position. Your handle would be too large.

[Slidewinder]

Thankyou Tinus for your comments.

Re: Rowing Handle
If you look closely at the video you can probably see that I removed the plastic chain port and associated hardware and repositioned the PM to the top of the flywheel housing. This opened up a corridor down the left hand side of the flywheel housing which easily accommodates the nose of the prototype handle - so there is no appreciable difference in the maximum extension at the catch when using the new handle. So it is meant as an add-on device (requiring some minor modifications to the C2 machine).

I don't have a lot of interest in manufacturing and marketing, but I've always enjoyed designing and building things. I saw a problem that needed a solution and I'm satisfied with the final result. I'm sure things will unfold as they should.

Re: Skate Machine

You'll be interested to know that the flywheel in that machine was taken from my old Model B. The "Slidewinder" skate machine had some local media interest and also appeared on "The Daily Planet"
TV show. It just came back from a hockey training facility in Toronto where it was very well received by the trainers and athletes. I asked them for constructive criticism and it was their opinion that if I could increase the stride width as you also suggest, then I would have a winner.

To widen the stride width it would just be a matter of reconfiguring certain elements. It's a prototype device, constructed to test the viability of certain concepts. There are number of ways in which it could be refined and improved. The foot platens, for example, could be made lighter, lower, more compact, if different materials were used. Even at its current state of development, it does work those skating muscles in an action that's natural, smooth, and flowing. I enjoy using it.

I'm focused on another project right now so the skate machine will be on the back burner until I finish what I'm working on - probably later this year. I'm not a very good multi-tasker. One thing at a time.

[Slidewinder]

Hi John Rupp:
Thankyou for your positive response.
To satisfy my curiousity, last night I fixed a rope and two handgrips to the chain of my Model D and gave it a go. You are correct, it is a huge improvement over the rigid, single-piece handle supplied with the machine - and very, very simple. Well done.

You are also correct (as expressed in an earlier private communication) that the articulated handle I designed functions similarly to the rope/handgrip configuration. The "Slidewinder" handle though, shares none of the weaknesses of the rope/handgrip configuration, and enables certain stroke geometries not possible at all using the rope/handgrip configuration. As follows:

- The corridor down the left hand side of the flywheel housing on the Model C and D better accommodates the narrow nose of the "Slidewinder" handle than the "V" of a rope/handgrip configuration.(I'm making a bit of an assumption here because I was unable, for some reason, to access the photo of your innovation)

- The structure of the "Slidewinder" handle prevents the handgrips from clashing together regardless of the user's handgrip movements. The same cannot be said for the rope/handgrip configuration.

- Most interestingly, the "Slidewinder" handle enables a left hand over right hand sculling action. This movement is not possible using the rope/handgrip configuration. While it's true that when using the rope/handgrip configuration, your left hand can cross over the right hand at the catch, but the moment you start to pull, your hands will immediately move from that hand over hand position to a horizontally aligned position (try it).

The explanation of why this occurs, and how the "Slidewinder" handle solves this problem will probably put many forum readers to sleep, so I'll send you a private message explaining this in detail.

[Tinus]

If you look closely at the video you can probably see that I removed the plastic chain port and associated hardware and repositioned the PM to the top of the flywheel housing. This opened up a corridor down the left hand side of the flywheel housing which easily accommodates the nose of the prototype handle

Aha, I didn't look closely. I was already wondered about what you meant with the corridor which you mentioned in an earlier post.

[paul s]

I'm not a very good multi-tasker. One thing at a time.

As a friend of mine puts it, he multi-tasks sequentially.

Paul S

[johnlvs2run]

Hi Robert,

Thank you for trying the rope/handles configuration.

The corridor down the left hand side of the flywheel housing on the Model C and D better accommodates the narrow nose of the "Slidewinder" handle than the "V" of a rope/handgrip configuration.(I'm making a bit of an assumption here because I was unable, for some reason, to access the photo of your innovation)

I like the corridor idea. I did not need that myself due to not going as far forward, but would also enable it were I to get another C2 (sometime in the distant future if ever). It seems to me the corridor would benefit the rope setup going farther forward, the same as with your design. Both designs have the V from handles to connection, so there is not much difference in that regard. Does anyone else not see the photos? I will see about linking them to a different site.

The structure of the "Slidewinder" handle prevents the handgrips from clashing together regardless of the user's handgrip movements. The same cannot be said for the rope/handgrip configuration.

I like that the handgrips go together.

Most interestingly, the "Slidewinder" handle enables a left hand over right hand sculling action. This movement is not possible using the rope/handgrip configuration. While it's true that when using the rope/handgrip configuration, your left hand can cross over the right hand at the catch, but the moment you start to pull, your hands will immediately move from that hand over hand position to a horizontally aligned position (try it).

But the same thing happens with the SW, at least as shown in the video.

[Slidewinder]

Hello John Rupp,
Re: Your April 9 posting
My observation that the hand over hand sculling action is not feasible using a rope/handgrip configuration is also supported by tests conducted during the development of the Slidewinder handle. All tests by myself and others confirmed that a simple flexible structure offers no resistance to the lateral force component of this action and the hands will move too rapidly from a hand over hand position to a horizontally aligned position. For short duration workouts, the user can prevent this by tensing the arm and shoulder muscles, but this is unnatural and tiring and cannot be sustained.

The knobs you see me adjusting in the video, control the friction of a uni-directional clutch contained in the barrel just forward of each handgrip. This enables the user to control of the rate at which the hands move from a vertically aligned to a horizontally aligned position. You expressed to me in a private message that you have little interest in exercising using this hand over hand sculling action. That's fine. The new handle doesn't force anyone to use that stroke geometry. It's an option. Loosening the knobs will completely disengage the described clutch action.

For serious scullers though, I suspect this option will be appealing, because it more specifically targets the muscles used during actual on-water sculling - and maintains user bio-mechanical integrity while accomplishing this.

Please watch the video again. My hands are moving from the hand over hand to the horizontal position in a very controlled manner. It's not an "immediate" or sudden action. The rate of that movement is completely controllable by tightening or loosening the knobs on the handgrip barrels. If anyone is interested I will explain in detail in a future post how and why this works.

One final point: The Slidewinder handle does not share the "V" geometry of the rope/handle configuration, as you suggest. The basic structure is two "L's" back to back. This creates a narrow front section that can easily pass down the corridor opened up down the left side of the flywheel housing.

Robert

[Slidewinder]

People seem to be wilfully blind to the design flaws of the Concept 2 ergometer. I mentioned elsewhere (SkiErg forum) how the C2 indoor rower has almost achieved the status of a holy icon - an object immune from all criticism.
If anyone complains about some aspect of the C2 rower, they are inevitably told that the fault lies with them, not the machine. Suffering from repetitive stress injury? It's because of your poor technique. Foot straps loosening? Simple, just wrap the strap end one more time under and around itself. Shirt tail getting caught under the seat roller? Stop whining and wear a tighter, shorter garment. It's rarely suggested that these complaints stem from actual design deficiencies in the machine itself, and could be corrected.

Consider the primary topic of this thread: the angulation of the wrist joints at the completion of the stroke. This is a glaring bio-mechanical defect, caused entirely by the handle supplied with the machine.
It should be a major issue for everyone, but rowing coaches, athletes, professors of kinesiology, and many others who should know better, continue like hired pitch-men to sing unqualified praises for the Concept 2 machine. It's baffling.

In a past C2 newsletter, there is a photo of a well-known professor of bio-mechanics astride a C2 ergometer. He's leaning back, clutching the handle. There's a grin on his face, and his wrists are bent like someone suffering from advanced arthritis.

I e-mailed that good doctor, and also some of his colleagues. I asked them why they never mention this obvious bio-mechanical flaw in any of their public comments about the C2 machine. I'm still waiting for their replies.

[Couloirman]

so, is there a place where we can purchase the slidewinder handle or is it not for sale? It looks like a pretty nice design overall. I usually only hold my handle with my index, middle and third finger(letting my pinky dangle off the edge) to get a wider grip and as the handle approaches my chest I slide off a little bit more so I only have 2 fingers on each side of the handle and that helps a little for me with the ergonomics but the slidewinder looks much better than the stock handle and Id love to get my grubby little hands on something like it.

[Slidewinder]

Couloirman,
I appreciate your "thumbs up" to the handle design, but I have nothing for sale. Only two of those handles exist - the one in the video and one in a carrying case. Also, it wouldn't be appropriate to use the C2 forum to advertise and sell a product.

I think most owners and users of the C2 indoor rower believe that the machine has, after almost thirty years, reached a level of perfection that would be almost impossible to improve. I wanted to show those people that their cherished C2 machine certainly can be improved, and improved dramatically - that contrary to their long held belief, the full potential of the Concept 2 ergometer has never been realized.
Robert

[Slidewinder]

The C2 ergometer is a machine, and the user of the machine is a human being. The handle is therefore the human/machine interface. A good handle design is one that makes the human/machine interface as seamless as possible. The human should not be forced to accommodate the machine - the machine should be designed to accommodate the natural movements of the human. By this criteria, the C2 stock handle is an abysmal human/machine interface. It's a rigid stick. It does not in any way accommodate the natural positional changes of the hands and arms as the stroke progresses.

Why, after almost thirty years, has Concept 2 not recognized and corrected this problem?

In the evolution of rowing machine technology, the "Slidewinder" handle is the missing link. It creates a seamless human/machine interface. It adapts so well to the user's natural movements that essentially, it disappears. Mechanically, the user and the machine become one.

I predict that future ergometer users will look back and wonder why everyone tolerated the rigid, single-piece handle for so long.

[Tinus]

Would it be allowed to change the handle in a competition? Or else, when making a world record attempt?

[NavigationHazard]

3.Machines with modifications not initiated by Concept2 Inc. cannot be used for the Ranking pieces.

From the "Rankings" page. Presumably then the answer to your question is "no" unless you're (say) swapping a plastic handle for one of the old wooden ones, or vice versa.