Slides Under The Indoor Rower

[old] jamesg · Post by **[old] jamesg** » December 21st, 2004, 2:24 am

I used a pair of roller skis cut in half, joined crossways by two planks for the erg feet, plus strips of wood lengthwise, all screwed together, and put the erg on top. Had to use a channel in the terrace floor to avoid it drifting sideways, and some old rope to stop end to end drift. The strips were very elastic and the result was a bit bouncy, so I tended to get seasick. I saw very clearly the effect that slides have (or rather the effects of not having to accelerate my mass any more), when doing the 100m tests. I did this because it's the condition that shows the effect best and because I wasn't fit enough to go flat out 8 times for more than 100m. I was't interested in demonstrating anything at all, just observing, and I hope Newton doesn't need any demonstration anyway. We have the sun and the planets and the moon to do that for us, not to speak of having to buy gas (petrol) to make cars go. What I did demonstrate, come to think of it and modestly enough, is that my technique is perfect, my strength superhuman, my endurance unbeatable. Or would be. Must be old age that puts the brakes on. Both sliders and fixed machines keep us fit, their design purpose, if we use them, so it's all academic to some extent. I do think the slides are better for oarsmen though, because the quick catch and the easy recovery are more like a boat. A single weighs 15kg as against my 90... This is the main point in the slides vs fixed topic. How to avoid the damage and bad habits that the fixed erg forces on us, especially when there is so much concentration on pbs, intervals, high ratings and similar nonsense which have nothing to do with sculling, rowing or even keeping fit. But then I suppose we have to release our killer instincts somehow and hammering the erg rather than the wife keeps us out of jail.. I often wonder if the word jail, gaol, comes from galera, those ships that used a lot of galley slaves. Back to basics. Maybe the only way is never to rate more than 22 on the erg, at which rating the inertial forces are minimal, so there's no diff between slides and fixed. I'd like to hear a coaches opinion: what does he have to do to teach ergers to scull or row?

[old] Mel Harbour · Post by **[old] Mel Harbour** » December 21st, 2004, 5:39 am

Actually, the origin of the word 'gaol' is from the word 'cavea' meaning 'cage' (Classical Latin). But I guess the galley thought is a fun one!

[old] jamesg · Post by **[old] jamesg** » December 21st, 2004, 6:46 am

In Italian, we use the words Prigione, Carcere, and also Galera. Important to stay out of all of them, but especially the last: they had oars. <a href='http://www.modellismo.net/articoli/anb21.html' target='_blank'>Galera</a>

[old] c2jonw · Post by **[old] c2jonw** » December 21st, 2004, 9:11 am

</div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td class='genmed'>QUOTE (PaulS @ Dec 20 2004, 09:49 PM)</td></tr><tr><td class='quote'>Hey C2Jon, can you get the Hagerman study back up on the web to help with this discussion?  </td></tr></table> Paul- I don't believe that we ever had it up on the web as it is mostly raw data and graphs. To summarize breifly, the study was undertaken to determine energy cost of fixed vs slide rowing with the C2 erg. The study group were untrained but healthy male and female subjects age 18-30. Training was conducted over a 36 week period, starting with brief low intensity workouts and culminating in a mixture of high intensity anaerobic and aerobic sessions. Data was collected for heart rate and absolute and relative VO2 over a range of 80-340 watts both on and off the slides. At most energy outputs for the males the absolute and relative VO2 and heartrate indicated higher energy costs on the slides. For women the differences were less noticable, showing similar VO2 values over the power range, but heartrate responses slightly favoring the fixed erg at lower power and the slides at higher power. JonW

[old] Mel Harbour · Post by **[old] Mel Harbour** » December 21st, 2004, 9:58 am

So unfortunately, there's no way of telling whether there is any effect in that set of data from problems such as the skill required to row. Since the subjects were untrained, you've got no background on their skill as a rower. So it's possible (not saying true/untrue) that the difference in energy requirements might be related to slides requiring a higher skill level to row efficiently on (for example co-ordinate the change of direction). Unfortunately I can't think how to overcome this in experimental design. Mel

[old] PaulS · Post by **[old] PaulS** » December 21st, 2004, 11:34 am

Thanks Jon, Was it published in a C2 Update? I'm certain I've read it, but apparently not certain "where" I read it. Mel - So you would not consider 36 weeks enough training time to become reasonably skilled? Jamesg - Newton would not accept the notion of a "Fixed" Erg. At least not when it is fixed merely to a Planet.

[old] Mel Harbour · Post by **[old] Mel Harbour** » December 21st, 2004, 12:28 pm

Not necessarily. It depends too much on exactly what the starting point was and how much they trained and with whom coaching. Also, did they all train on both machines, in which case did they train equally on both machines? Or did they learn to specialise on one machine more than the other? There are also problems with the interpretation of the results. You could quite easily draw a different set of conclusions from the results. How about: 'It is easier for a group of untrained rowers to become skilled and efficient while rowing a static ergometer than it is on a dynamic ergometer'. Mel

[old] PaulS · Post by **[old] PaulS** » December 21st, 2004, 12:41 pm

Mel - Points noted, but that is why a researcher with vast experience directly related to Rowing was selected. (Or maybe it was just luck.) The Norwegians appear to have replicated the study, and unless you are willing to assume they are incompetent researchers, the results seem to be validated. Your final interpretation flies in teh face of much anectdotal evidence that would suggest the slides benefit the least skilled rowers far more than the more skilled ones. Finally you mention coaching, which would directly relate to what "good technique" is in the first place. I think that issue has been settled, and so do you, but we disagree plently.

[old] grandslam · Post by **[old] grandslam** » December 21st, 2004, 3:03 pm

</div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td class='genmed'>QUOTE (tomhz @ Dec 20 2004, 12:23 PM)</td></tr><tr><td class='quote'>And Byron is right too: The calculations in <a href='http://www-atm.physics.ox.ac.uk/rowing/ ... meter.html' target='_blank'>http://www-atm.physics.ox.ac.uk/rowing/ ... /a> are OK. Mathematics and physics don't lie. </td></tr></table> Well, the mathmatics and physics don't lie, but the figures used in this article were WAY off. The numbers inputed into the equations on that site were provided by the Rowperfect company. The difference in erg to rower weight is not 6/1 as it might be in a boat. The erg plus the floating parts of the slides weigh almost 32kg. Add to that body wieght not centered on the seat that is not accelerated (ie feet, lower legs- 10kg; sit on a scale at the catch and the release to see this) and that brings the mass of the erg to about 42kg in my case, vs (86kg - 10kg) 76kg body mass to accelerate. This is certainly a rough estimate, but less than 2/1 body to erg, not 6/1. In addition, on slides, you do not have the benefit of saving and releasing potential energy (ie you cannot slam into the catch and store energy in your tendons or "bounce" off the catch) that you have on a static erg. The article "assumes" no stored energy at the catch on the static erg, which of course is false. Lastly, while it's true one can rate higher because of a faster catch on slides, this is offset to some degree by the fact that faster acceleration to achieve the higher rating has a high energy cost (2x the rate takes 3x the energy). The results of my own experiment of one? Heart rate equal on slides vs static erg at any given pace, but I get about 1 second/500 faster times on slides, as Paul F. does. Why? You tell me. I used to row on water, and would never row a static erg again. You want to simulate rowing you need slides to make the erg into a rowing machine. Static ergs are just weight machines for a good workout. Cheers, Jeff Sauter

[old] PaulS · Post by **[old] PaulS** » December 21st, 2004, 3:11 pm

Jeff, Does your 1 sec/500M slide advantage happen at the same Stroke rate? The "stored energy" that you mention as being in the tendons is actually wasted energy (mostly heat). You can reduce that waste though good recovery technique on the ground bound Ergo, and as you do that, your times will converge between the Slide/Ground conditions.

[old] grandslam · Post by **[old] grandslam** » December 21st, 2004, 4:08 pm

No Paul, I always row at a higher rate on slides (4-5 strokes/min). It just "feels right" and because of the faster catch, I can. I agree much of the stored energy at the catch (static erg) is watsted as heat, but some is recovered, depending on how hard the erger slams into the catch. Maybe I'm looking at this backwards. Since I was trained to never slam the catch in a boat, I'm losing the advantage of storing that energy on the static erg since all my energy is wasted as heat decelerating to a complete stop at the catch. Jeff

[old] PaulS · Post by **[old] PaulS** » December 21st, 2004, 5:27 pm

4-5 strokes per minute is HUGE in terms to only gaining 1 sec/500M. Whether you think you are or not, you are "slamming into the catch" on the slides, but just not being penalized for it as you would be on the ground or in a boat (we can't feel the system speed slowing in a boat, since we are not directly connected to it). If you were coming to the catch as controlled as you think, your rate would not vary so much. I'd wager that rating very high (30+) while strapless is quite difficult for you on the grounded Erg, but no problem on slides. This would be due to a sluggish recovery of the body that leads to an acceleration into the frontstops rather than decceleration. i.e. you will feel quite a bit of pressure from the straps when on the ground, less on slides since the bungee and slide slope move the Erg pretty quickly on their own (when trying to counter your body mass). Even just the slope of the rail moves the entire Erg quite quickly, slide the seat out to the end and sit straight down on it to see for yourself if you don't believe me. There have been a few kinematic analyses of the differences between "static" and "dynamic" Ergo situations, and a factor that stands out consistently is that stroke length shortens in the "dynamic" situation, which is directly related to not being able to use momentum as an aid to compression at the catch. This is similar to the situation in a 1x, but once in a team boat it is easily possible to use that momentum, however it makes the catch timing nearly impossible and at the same time creates a larger fluctuation of hull speed around the system speed, which kills efficiency.

[old] grandslam · Post by **[old] grandslam** » December 21st, 2004, 10:34 pm

I agree slamming into the catch is a boat stopper on the water, but maybe an advantage on an erg. You can compress, get a longer stroke (as you said), and then recover some of that energy stored in the compression. Naturally a longer stroke equals a lower rate; and if you say the stroke is shorter on slides, wouldn't you HAVE to row at a higher rate to achieve the same score at a constant effort on slides? I just tried "slamming" the catch on slides, and I immediately started hitting the stops. Rowing strapless on a grounded erg at 30+ is difficult because you have to stop your mass somehow if you don't have straps, and it takes longer to come around at the recovery if that's what you mean by "sluggish" body. I haven't had my technique examined by an expert/coach since college, but it was quite good back in the day (so I was told). Xeno's rowing studio is nearby; maybe I'll have him take a look . Cheers, Jeff Sauter

[old] PaulS · Post by **[old] PaulS** » December 22nd, 2004, 11:48 am

Okay, so there are a couple differences going on here. You seem to be saying that if something produces a better pace on the Erg, even if it would destroy boatspeed, it's "better" Erg Technique. This might be true, but with the evidence being that the fastest Erg times in the World have been accomplished by competent Rowers, it is at least up in the air. I do agree that there are techniques that could be taken advantage of on the Erg, to get a faster time (this happens all the time when a coach is relying on Erg times to pick boats), and would be uncacceptable techniques in a boat. However good rowing technique transfers directly to doing this. I've often said that as the Erg specialists evolve, there will likely be a divergence in technique and they will probably produce the fastest times ever seen on the Erg, but that may take a while. Stroke length differences: The extra compression places the knee at a very weak angle to begin the drive, so this "extra length" may or may not be very useful. (of course this opposes the slide advantage as you have described). On slides, you say that you get a quicker catch, which means a quicker increase in handle pressure, which would increase the area under the force curve early in the stroke, also cancelling the effect. More force means more work over a given time. It is common to find that the force profile when on the slides and when off them are significantly different. This has been used as an argument to say that the "dynamic" Erg is a better Boat simulator. (But this is done in the context of Marketing a dynamic Ergo) My take on this is that the closer that the force profiles match, between slides and ground (and boat) the better. The boat of course requires some additional skills with regard to getting the blade in the water, which would alter the eventual profile from the Ergo in ways that are very difficult to quantify, and frankly are the responsibility of the Athlete to monitor, however if the athlete does not know what it feels like they won't be able to do this. You should always stop your mass at the finish with handle pressure, if you are using the straps to do that, the PM doesn't see "all that power" so it was wasted. Recovering the body is a very difficult exercise, in fact no matter at what pace you are pulling it is difficult, and becomes more difficult as it must be performed more quickly at higher rates. This is one of my disagreements with low rate (exaggerated high ratio) training, as it completely allows for sluggishness to become a habit and leaves the athlete completely unprepared to bring the rate up skillfully. Take some video and post it, those have always been fun in the past, and you will get a considerable amount of feedback. Obviously the resource of being able to drop into the Iron Oarsman is great, and you should do that.

[old] grandslam · Post by **[old] grandslam** » December 28th, 2004, 3:18 pm

Thanks for the thought out response Paul. I think I'll hit the Iron Oarsman for a few tips before submitting that video though . BTW, can I split the signal from my rower to two computers; one for Rowpro, and one with an Erg Monitor display? Cheers, Jeff Sauter

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