Slides Under The Indoor Rower

[old] dfcox · Post by **[old] dfcox** » December 12th, 2004, 6:22 pm

Age: 73 years, 9 months Weight 200 pounds Height 6'5" I started rowing in the fall of 1949 at Cornell University. After stepping out of a boat after the IRA (3 Miles) in 1953, my on water rowing essentially ceased. Last 14 years on the indoor rower, now a model D with slides. Approximately 18.5 million meters logged. A 7:51 2k at Madison's Midwinter Melt Down last February and recently a 43:46 10K. When I put the slides under the indoor rower I wondered if it would improve my times. Looked for experimental evidence and found none. I decided to run an experiment. I rowed 6k pieces at a "just row" pace with my heart running at about 70% of its possible range. I used the slides one day and the rowed without slides the next for a total of 20 days. I found the following: Time in minutes: Without the slide: 27.68 With the slide: 27.35 Difference +0.33 Heart Rate in beats per minute: Without the slide: 120 With the slide: 124 Difference -4 Stroke Rate in strokes per minute: Without the slide : 22 With the slide: 27 Difference -5 I could dress this up with the standard erros and P-values of formal statistical analysis but I doubt that would help many. So I will state conclusions. 1. Without any intent or plan, just sitting down to row 6K, the stroke rate increased from 22 to 27 strokes per minutes when I used the slides. There is less than one chance in 1000 that this was due to chance. 2. A small increase in heart rate occurred using the slides but this could easily have arisen by chance. 3. The difference in the time to row 6k, 0.33 minutes (20 seconds) is small. I am 95% sure the true difference lies between -0.37 and 1.03 minutes. Obvious questions. 1. This represents one old man's experience, what would happen with other people and other techniques and younger ages, etc, etc. 2. What would happen using a race pace over 2K? 3. What would happen if an effort was made to keep the stroke rates equal? 4. And a thousand other questions. I would be interested in references to other experimental work where the issue was studied. Also interested in experiences and general thoughts on the question. This forum is replete with conjectures and opinions about techniques and training methods and very little experimental evidence supports them. I remain very skeptical until I see experiments, designed controlled studies, clinical trials, call them what you will. Obviously a grouchy old man. (For Cornellians reading this I add...BMA) [Dave Cox dfcox@mchsi.com]

[old] Canoeist · Post by **[old] Canoeist** » December 12th, 2004, 8:38 pm

Dave, I am glad to see that someone else has an experimental mind. I have set up and performed tests for the slides also. (And also erg jacking, and high feet) About 2 years ago, I set up some tests where I would row at a constant pace, 1K on slides, stop the slide motion for 1K, repeat 5 times. I watched my heart rate and there really was no drop in HR when I allowed the slides to slide. I rowed at easy, medium, and hard paces. I rowed at "free spm" on the slides and at the same rate on slides as stationary. Having proven to myself that there is no difference in performance between slides and stationary, my PBs show that I am about 1 second/500m faster on slides - at all distances from 500m to marathon. Cheers, Paul Flack

[old] Ralph Earle · Post by **[old] Ralph Earle** » December 12th, 2004, 9:05 pm

Perhaps it was due to much less experience on the slides, but you were more efficient on the stationary erg than on the slides: 1.81meters/heartbeat vs 1.77m/hb. You might look at your m/hb for each experimental condition over the 20 days to see if efficiency on the stationary erg did not change, but that on the slides increased.

[old] Dickie · Post by **[old] Dickie** » December 13th, 2004, 11:22 am

Sorry guys but all your testing is less than meaningless. In order to run an objective test that has at least some meaning you would need many more participants and extend the test over many months. among the participants you would need a control group against which to measure. In most testing your control group would not know that they are the control group, as in drug testing, they give some people placebos and only the researchers know who gets what. This would be next to impossible with testing on an erg with slides, so you would need more people and more time and a very specific training regimen. All of this is necessary to take out any bias one way or the other and to minimize the effects of other factors, such as how you feel that day, your diet, your level of sleep and on and on and on. This is a question that will probably never be answered, at least until someone is willing to pony up some major cash for a legitimate study. So get over it.. Fred Dickie

[old] Canoeist · Post by **[old] Canoeist** » December 13th, 2004, 11:47 am

I agree with you Fred that there isn't really a good way to test one method versus the other. But I do know that I find it easier to row with slides. It may be entirely due to the placebo effect, but it works for me. Paul Flack

[old] PaulS · Post by **[old] PaulS** » December 14th, 2004, 11:10 am

Can't this be put to bed? Fritx Hagerman did a scientific study regarding this and found a slight difference, higher cardiac output, when on slides. There was also a Norwegian Study that showed teh same thing. Both were done with control groups, Stroke rate controls, etc... The one thing that did seem to still be overlooked was the possibility of "practice effects", however my observation has been that the less skilled the person the more difference they see on the slides, and they tend to interpret that as an advantage to being on the slides because they are maintaining a faster pace at a higher stroke rate. That alone would be contrary to speculating that the results of the controlled studies were due to the participants (who were described as "skilled rowers") lack of technical expertise on the slides. The Hagerman Study used to be linked off the C2 site, but I can't find the link now. Both of the studies mentioned were discussed in the old forum a few years ago. I appreciate the "show me the study" attitude, but it's been done, and even tracks quite well with what you found, in spite of your exercise being less than scientifically controlled. My paraphrase of the conclusion to both studies was that even though there seemed to be a slightly higher output requirement when on slides, that difference was small enough to be inconclusive. This lead to the inclusion of times accomplished on Slides to be elligible for the World Ranking, where they had previously not been, because even the folks at C2 had the "intuitive" notion that there might be an advantage and wanted to make sure that was not the case before lumping all the scores together. Pretty altruistic on their part! Hard to imagine the litteral interpretation of that policy: "Hey, we have this great new product that makes the Erg an even better training tool for rowers, but all the times you happen to log when using it are not elligible in the ranking tables. Yeah we realize you are a highly competitive bunch, that likes the ranking, so this will reduce your intrest in the product, but until we know for sure that fairness is maintained this is the way it is." - Pretty poor marketing, IMO. I'm glad they finally worked it out.

[old] Everard · Post by **[old] Everard** » December 14th, 2004, 7:18 pm

What are you guys talking about? I notice the categories of entries of rowing times are standard, on water ond on slides. Who or what is a slide? On the rower I use the seat slides backwards and forwards. Are there other rowers where the feet move instead? I would have thought that the standard would be for the seat to move. Does it make all my entries invalid if I've entered them as type "standard"? PS What hapens to my entries if my weight changes? At present I hover around 165 pounds. Sorry to be dumb but the FAQs don't seem to cover either of these topics. Everard

[old] andyArvid · Post by **[old] andyArvid** » December 14th, 2004, 9:13 pm

</div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td class='genmed'>QUOTE (Everard @ Dec 14 2004, 08:18 PM)</td></tr><tr><td class='quote'>What are you guys talking about? I notice the categories of entries of rowing times are standard, on water ond on slides. Who or what is a slide? On the rower I use the seat slides backwards and forwards. Are there other rowers where the feet move instead? I would have thought that the standard would be for the seat to move. Does it make all my entries invalid if I've entered them as type "standard"? PS What hapens to my entries if my weight changes? At present I hover around 165 pounds. Sorry to be dumb but the FAQs don't seem to cover either of these topics. Everard </td></tr></table> <a href='http://www.concept2.com/products/slides/slides.asp' target='_blank'>Slides (click here)</a> <img src='http://www.concept2.com/media/slide_irn.gif' border='0' alt='user posted image' />

[old] dfcox · Post by **[old] dfcox** » December 16th, 2004, 7:32 pm

I posted some experience and asked some questions on 12/12. I asked if anyone knew of references to other experimental work. I got no references but assurances they exist. I asked for experiences and thoughts and I thank you for those. I will respond by poster. Canoeist: Yes you can learn much about yourself and the machine by doing experiments. I enjoy the process and find it informative and helpful. You have done much more than I have. I remain a bit more optomistic about the possibilities of experimentation involving several people than you do. But I do not know. See below. Ralph Earle: Most tend to like ratios. The ratio of meters to heartbeats which you call efficiency an example. However, for me, the ratios of correlated random variables have complicated distributions which I find difficult to handle and think about. However, the world seems to find them helpful and we have price to earnings ratios and odd rations to assess risks and feed efficiencies. If you find them helpful in understanding the underlying phenomena, by all means use them. No arguement. Dickie: What does "less than meaningless" mean? The test I ran with my machine stationary and on slides had real meaning for me. The inference strictly limited to me and I do not and did not claim otherwise. But I have a better understanding of mine capabilities and the machine's function by running such experiments. The protocols of experimental science we now accept only entered the world in the 20th century. Books exist on the design of experiments and academic people do research on new and better ways to use the process. The experiment you describe as the one needed to estimate the difference between slides and no slides, an experiment containing two groups of people, some using slides and some using no slides would be very inefficent and require large sample sizes. That comes about because the differences among people will generally represent the largest source of variation you face. People differ, almost everyone agrees. Experimental designers have recognized that and suggested one alternative. Get each person to use the slide and the stationary erg. Then the comparison among the two can block out the person to person variation. Such experimental designs, called cross over designs, have found use in medical, psychological and agricultural research for a long time and with FDA and general scientific acceptance. (I can give your references, for example, W.G Cochran's book, "Experimental Designs.") One can not always use the designs, it depends on the trait measured, carry over effects and such. But when possible they provide a very efficent alternative to the two group approach. Many extensions of the idea exisit. You can call one of these treatments the "control" if you like but I see no need for that terminolgy here. I simply want to understand the size of the difference between the two ways of using the erg. I believe I could do a very meaningful, precise, experiement using a cross over design and 20 or 30 people. Any colleigate rowing program could build it into its winter training program without interfering with the training and I believe the guys would enjoy it and it would serve to relieve the boredom of winter training. Any fitness center with a few ergs could do it and it would increase the interest in the machine. Physical education courses could include it as a possible term project. We could even organize such a study using this forum. What do you want me to "get over?" That experimental science, science that uses randomized and replicated studies, have no part in establishing "causal" inference? What else do we have to do that? That the experiments required seem hopelessly large and expensive. As I explained above, I think not. I suspect in the 19th century and for hundreds of years before that occasionally someone asked if bleeding and purging sick people really aided their recovery. Almost surely the experienced hands in the field told them that people varied so much we will never know and the Greeks did it so get over it and put those ideas to bed. They did. And people died regualrly from the treatments they received. PaulS. I could "put it to bed" if I could read about the design used and see the difference found and had some idea of its precision. I would think Concept2 would keep a reference list of studies that use their machine but apparently they do not. You assure me that the question has been settled. I hope you tell the next generation because it will prove hard for them to read about it. The studies you describe seem to imply the use of two groups rather than the cross over approach I outlined above. What sorts of sample sizes did they employ, what sort of precision did they achieve? You do not need to answer these questions. Being told to "get over it" and "put it to bed" reminds me of what we used to say to guys in the eight oared boats who talked too much and dared to suggest something that might improve the run. The command was simple and direct, namely, "Shut up and row!" I will do that guys. Thanks, I enjoyed my venture here. Dave

[old] Mike McGuirk · Post by **[old] Mike McGuirk** » December 16th, 2004, 10:34 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td class='genmed'>QUOTE </td></tr><tr><td class='quote'> Being told to "get over it" and "put it to bed" reminds me of what we used to say to guys in the eight oared boats who talked too much and dared to suggest something that might improve the run. The command was simple and direct, namely, "Shut up and row!" I will do that guys. Thanks, I enjoyed my venture here. </td></tr></table> Hey, Dave - don't go. Stick around. The forum could use your input. You unfortunately got zapped by a couple of regulars who have been through this discussion so many times that they are tired of it. There are others of us out there that are very interested in your experiences and ideas. Keep talking. BMA, MM P.S. In my experience on and off slides, the biggest difference is the ease with which one can attain a higher stroke rate on slides. When I hold stroke rate and pace constant, there seems to be no difference in perceived effort slides vs. stationary. Also I find that HR is so variable with numerous extraneous influences that it is pretty useless as a comparative measure from one day to the next. MM

[old] honorcaddy · Post by **[old] honorcaddy** » December 17th, 2004, 1:24 am

I read with interest all of the "slides" posts because I just bought slides for my Concept C. I have a related question for those of you who row on water. Do (or can) slides improve sculling technique? Are there any differences in training technique when using slides? Any suggestions on how to start out using the slides for training? Thanks

[old] jamesg · Post by **[old] jamesg** » December 17th, 2004, 11:55 am

I think the erg on slides is much nearer a 1x, technique wise, than the erg aground. On slides the catch is quicker, and has to be taken with more "squeeze", as afloat; the recovery is much easier and needs more control, again as afloat (otherwise leading to the higher ratings often seen). If you're a sculler but use a fixed erg, I reckon it's best to think of them as two entirely different things needing differing techniques, in particular at the catch. Slides can help here, being more similar to a boat. As to training programmes, I'd say there's no difference to a fixed erg, but as a sculler I wouldn't use the erg for anything but CV work, it's design purpose. For this it's perfect, you'll have hard hands and rear right from day one and can concentrate on steering, navigation, balance, going thru wash without falling in and all the technical aspects right from the start, so it's much more fun. As to slides being "faster", it's not as if it suddenly became an aerodynamic bike.. However there is less work to do on the slides because the CG of the erger/machine becomes stationary. On the fixed erg we have to accelerate our mass twice every stroke. How to get that "less work" or saving to the handle and so spend it on the flywheel is another problem. Unlikely to be automatic, in any case. We have to pull harder, longer (this is probably the major factor, due to the quicker and so shorter catch on slides) or at higher rating. The result will depend on the erger and specifically if he has the technique and training to do it. If he doesn't pull harder longer or faster, the counter won't see anything different. Any experiment can only show whether or not the erger knows how and/or has trained to do this. We don't need to test Newton, and the basic dynamics/ engineering/ physics is perfectly clear.

[old] Dickie · Post by **[old] Dickie** » December 17th, 2004, 3:29 pm

Dave You started your inquiry with a description of you experience (which is impressive) and then stated 'When I put the slides under the indoor rower I wondered if it would improve my times. Looked for experimental evidence and found none. I decided to run an experiment" Then you described your test and provided results. I then replied out of sheer frustration (i apologize for that), this subject has been beaten to death over the last 4 or more years. Your reply to me shows that you know far more than I do about what it takesw to put together a meaningful test to answer this question. You must, therefore, also know that your individual test as well as those done by Paul Flack do nothing to answer the question. (Less than meaningless) I have tried slides once and I also like the feel, I will buy my own set someday. I also am of the opinion that they do make a difference in times (physics says they must), but that is only an opinion as there has been no reliable testing done to answer the question. Fred Dickie

[old] PaulS · Post by **[old] PaulS** » December 17th, 2004, 5:00 pm

</div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td class='genmed'>QUOTE (Dickie @ Dec 17 2004, 11:29 AM)</td></tr><tr><td class='quote'> I also am of the opinion that they do make a difference in times (physics says they must), but that is only an opinion as there has been no reliable testing done to answer the question. Fred Dickie  </td></tr></table> When C2 approached Dr. Hagerman (who has been doing this type of testing for quite some time, and apparently is a quite credible guy in the field of physiological testing) to "Find out if there is an advantage for the Athlete when the Erg is on slides" (My guess as to what they requested.) I expect that he went about doing so in a similarly reliable manner as he had done in all of his previous research. Do you doubt that the research was done, that it is reliable, or that the results being discussed were in error? Why does "physics say" that a flywheel moving back and forth horizontally does not require as much energy as one in a relatively fixed position? I know, "different masses moving requires different energy", and therein lies the problem, that reasoning is a smoke screen to understanding why the differences are virtually non-existent in practice. Much of the energy that people waste when on a ground bound Erg and causes them to be very inefficient, but is forgiven (more or less) when the Erg is on slides, i.e. you simply can not get your body mass moving much when on slides and therefore do not have to stop it before changing directions. That's right, and you don't have to accelerate your body mass along with the handle on the drive, but you don't get to recover that momentum at the finish either. There is a series of trade-offs that simply cancel each other out nearly exactly. Final Exam question: Place an Erg on Slides and begin to row, add mass to the erg frame in some continuous way, when does it get more difficult to maintain pace? Extra Credit: If the Erg frame increased to near infinite mass (aside from the black hole problems, let's say it weghs as much as the Earth.) would it be impossible to pull the handle? Why or why not?

[old] Byron Drachman · Post by **[old] Byron Drachman** » December 18th, 2004, 5:02 pm

I've never tried the slides, so I have no idea what the effect is. However, not knowing anything about a subject has never stopped me from talking about it in the past, and I don't see any good reason why I should modify my behavior now. I did a google search and couldn't find the article by Hagerman. However, in this reference: <a href='http://www-atm.physics.ox.ac.uk/rowing/ ... meter.html' target='_blank'>http://www-atm.physics.ox.ac.uk/rowing/ ... if I go to section 13 (Effect of Rating), I see that approximately 37.5 watts are needed by a 75 kg rower in sliding his or her mass back and forth at 30 SPM. If I estimate the mass of the ergometer as 27 kg and assume the rower doesn't move but the ergometer moves back and forth on the slides, the watts used change to 13.5, so you would save 24 watts. For a heavier rower, the savings would be greater. Byron added after editing: When I assumed the rower doesn't move, of course that was a simplifcation. The rower would move some.

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