Weight Vs Length

[old] rspenger · Post by **[old] rspenger** » November 18th, 2005, 12:37 pm

A couple of points have been ignored in this thread. One is the limitation of stroke length in a boat. The blade is most efficient at 90 degrees to the hull and the efficiency falls off both forward and aft of that point. A really long stroke ends up wasting effort pushing away from the boat at the catch and pushing towards the boat at the finish. This doesn't apply to a chain and flywheel type rowing machine like the C2, where the pull is all on a straight line rather than an arc.<br /><br />A second point is that there is a need for a certain amount of uniformity in a crew, especially in sweep boats. A mismatched 2- would end up doing circles unless the more effective rower eases off and even in the fours and eights, a rower who is either much taller or much shorter than the others makes for a less efficient boat. This is not so critical in the 2x and 4x, but even there, it helps if the rowers have stroke lengths that are fairly even.<br /><br />Both of these points may well contribute to the fact that the top erger of all time, at about 206 cm, was not as successful on the water. <br /><br />Bob S.

[old] PaulS · Post by **[old] PaulS** » November 18th, 2005, 12:45 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(holm188 @ Nov 18 2005, 08:16 AM)</b></div></td></tr><tr><td class='quote'><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(PaulS @ Nov 18 2005, 09:36 PM)</b></div></td></tr><tr><td class='quote'>Still waiting for the proof of your unusually built "top" rowers. ID10T! <br /> </td></tr></table><br /><br />"<b> ID10T!</b>"<br /><br />Is that a new variation of S10MPS ?? <br /><br />Just a joke to lighten up the tension! <br /> </td></tr></table><br /><br />Nope, just an alphanumeric method of keeping track of certain folks.

[old] PaulS · Post by **[old] PaulS** » November 18th, 2005, 12:57 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(rspenger @ Nov 18 2005, 08:37 AM)</b></div></td></tr><tr><td class='quote'>A couple of points have been ignored in this thread. One is the limitation of stroke length in a boat. The blade is most efficient at 90 degrees to the hull and the efficiency falls off both forward and aft of that point. A really long stroke ends up wasting effort pushing away from the boat at the catch and pushing towards the boat at the finish. This doesn't apply to a chain and flywheel type rowing machine like the C2, where the pull is all on a straight line rather than an arc.<br /><br />A second point is that there is a need for a certain amount of uniformity in a crew, especially in sweep boats. A mismatched 2- would end up doing circles unless the more effective rower eases off and even in the fours and eights, a rower who is either much taller or much shorter than the others makes for a less efficient boat. This is not so critical in the 2x and 4x, but even there, it helps if the rowers have stroke lengths that are fairly even.<br /><br />Both of these points may well contribute to the fact that the top erger of all time, at about 206 cm, was not as successful on the water. <br /><br />Bob S. <br /> </td></tr></table><br /><br />Oh no! Not this again. Please study up on how a blade works before discussing it. The area you mention as "most efficient" is in reality the "least efficient" (the blade has stalled). Whether or not the handle travels in a arc or straight, also has little to do with it, the arc gains us some length in a boat, but the drive is still a more or less linear force along the line of boat travel. There is also no such thing as "boat pinch". Agree that sculling and Sweep are a little different, but that has to do with the constraints of the mechanics, if those are changed (<a href='http://www.powerathletics.com' target='_blank'>Balance point</a>) then the differences may be minimized.<br /><br />Being able to find enough similar rowers is probably why rather normal folks 6'1" - 6'5" end up being in the fastest boats in the world. ("normal" in the terms of the Rowing World) <br /><br />

[old] John Rupp · Post by **[old] John Rupp** » November 18th, 2005, 1:15 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(PaulS @ Nov 18 2005, 06:36 AM)</b></div></td></tr><tr><td class='quote'>John,<br /><br />I don't really have a need to boast[right] </td></tr></table><br /><br />Thank goodness, that sure makes things easier doesn't it! <br />

[old] PaulS · Post by **[old] PaulS** » November 18th, 2005, 1:24 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(John Rupp @ Nov 18 2005, 09:15 AM)</b></div></td></tr><tr><td class='quote'><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(PaulS @ Nov 18 2005, 06:36 AM)</b></div></td></tr><tr><td class='quote'>John,<br /><br />I don't really have a need to boast[right] </td></tr></table><br /><br />Thank goodness, that sure makes things easier doesn't it! <br /> </td></tr></table><br /><br />Yes. I've always said "Train Hard, Race Easy." I like things easy. <br />

[old] rspenger · Post by **[old] rspenger** » November 18th, 2005, 4:18 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(PaulS @ Nov 18 2005, 09:57 AM)</b></div></td></tr><tr><td class='quote'>Please study up on how a blade works before discussing it. The area you mention as "most efficient" is in reality the "least efficient" (the blade has stalled). Whether or not the handle travels in a arc or straight, also has little to do with it, the arc gains us some length in a boat, but the drive is still a more or less linear force along the line of boat travel. There is also no such thing as "boat pinch". <br /> </td></tr></table><br /><br />Right, I have never looked into it other than the simple physics of the lever, so I concede your point. However, the blade does move in an arc and there are limits beyond which it is not doing any good. The extreme would be parallel. I have never heard the term boat pinch, but I think I get the idea. But, having rowed both seats one and two, I have had experience with using the the blade parallel (slightly past parallel at the start) to the boat to keep aligned before the starts. In that manuever (with only one hand on the handle) I was just moving the bow of the shell sideways, not giving it any forward motion. The guy that holds onto the rudder at the start wouldn't be too happy if bow or number two gave a strong pull with the oar in the middle of the full arc.<br /><br />If a rower reaches on outboard of the pin (as is done in alignment), the oar has a possible full arc of 200 degrees or more. I doubt that anything beyond the middle 150 degrees or so of that arc is doing much for the forward motion of the boat.<br /><br />Bob S.

[old] rspenger · Post by **[old] rspenger** » November 18th, 2005, 5:16 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(rspenger @ Nov 18 2005, 01:18 PM)</b></div></td></tr><tr><td class='quote'>The guy that holds onto the rudder at the start wouldn't be too happy if bow or number two gave a strong pull with the oar in the middle of the full arc.<br /> </td></tr></table><br /><br />I should have amended this. The big wooden rudders, mounted on the sterns, are long gone from the racing shells, replaced by little plastic or metal gadgets, not much bigger than a postage stamps, hidden under the hull. I suppose that the guys in the starter skiffs have to somehow grab ahold of the sterns of the shells nowadays.<br /><br />Bob S.<br />

[old] PaulS · Post by **[old] PaulS** » November 18th, 2005, 5:17 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(rspenger @ Nov 18 2005, 12:18 PM)</b></div></td></tr><tr><td class='quote'><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(PaulS @ Nov 18 2005, 09:57 AM)</b></div></td></tr><tr><td class='quote'>Please study up on how a blade works before discussing it. The area you mention as "most efficient" is in reality the "least efficient" (the blade has stalled). Whether or not the handle travels in a arc or straight, also has little to do with it, the arc gains us some length in a boat, but the drive is still a more or less linear force along the line of boat travel. There is also no such thing as "boat pinch". <br /> </td></tr></table><br /><br />Right, I have never looked into it other than the simple physics of the lever, so I concede your point. However, the blade does move in an arc and there are limits beyond which it is not doing any good. The extreme would be parallel. I have never heard the term boat pinch, but I think I get the idea. But, having rowed both seats one and two, I have had experience with using the the blade parallel (slightly past parallel at the start) to the boat to keep aligned before the starts. In that manuever (with only one hand on the handle) I was just moving the bow of the shell sideways, not giving it any forward motion. The guy that holds onto the rudder at the start wouldn't be too happy if bow or number two gave a strong pull with the oar in the middle of the full arc.<br /><br />If a rower reaches on outboard of the pin (as is done in alignment), the oar has a possible full arc of 200 degrees or more. I doubt that anything beyond the middle 150 degrees or so of that arc is doing much for the forward motion of the boat.<br /><br />Bob S. <br /> </td></tr></table><br /><br />At the very longest, an Elite sculler may cover an Arc of 110deg and a Rower about 90. The finish angles will be in the 40-35deg range respectively. Leaving catch angles of 20 and 35. (Mel will come in and be pedantic about these, I'm just giving general figures that are "close enough" for our purpose.)<br /><br />You can see the Atkinsopht sight for a simulation of catch angle for scullers and it does seem to show that a catch angle lower than 10deg is not productive, however noone can get there anyway so we don't really know.<br /><br />What we do know is that "Catch Slip" (Defined by Kleshnev) or the arc covered before reaching 30% of Peak Force after the catch is made should be made as small as possible for the best boat speed. It follows that peak force should be reached ASAP after the catch to create the longest impulse.<br /><br />Finally, the blade does not move in an "arc" relative to the water, the tip ends up making what looks a lot like a comma (if the boat were the line of type), travelling toward the finish line for ~25%, Staying put for ~25%, toward the finish line for ~25% (slip), and once again toward the finish line for ~25% of the drive time.<br /><br />This happens as long as the blade is planted accurately and not rowed in and is somewhat independent of how much force is being generated at the handle. If the opportunity for early force generation is missed, the boat is moving, it will be lost.<br /><br />Shaft flex can extend the time that the blade is traveling toward the finish line and remaining stationary, by keeping the catch angle longer, but once it gets to ~80 the blade will slip unless there is no force on the handle (unlikely) creating all that white wash that some look at and go "wow! there is a lot of power!". they are partially right, but the power is going into tossing water about rather than moving the boat and it is short lived.<br /><br />This is so easy to illustrate with new (or old) rowers in a 2x by simply having a person row individually and showing them the speed difference that they can achieve (when going about it wrong) and the speed achieved when it is done correctly. The feel of the boat movement has a completely different character also. Unfortunately, how the boat is moving is very hard to tell while you are rowing since we are on a sliding seat and so many other things are going on.<br /><br />The situation of "sculling" a boat while at a stake boat misses one important thing about all the other time in rowing. <i>The boat is not moving forward</i>, So it is a unique case where "efficiency" is not at work at all.<br /><br />Perhaps I can get some resources posted up on the web, I'll have to ask Valery Kleshnev to make sure it is okay with him.<br /><br />

[old] ljwagner · Post by **[old] ljwagner** » November 20th, 2005, 12:01 pm

At the 1984 Olympics, the Romanian women won all the rowing events except the 8. They took silver, losing by about 2 feet. Those silver medalists all wore their MULTIPLE gold medals to the medal ceremony. I think one or two of them had 3. The US team rowed one person to one seat, no one rowed two races. The Romanians had about 8 woman and a spare, and raced all the events. <br /><br />Significance ?<br /> The eight Romanian women lined up were a hodgepodge of heights and builds from short and dumpy to tall and slender, and every mix in between. <br /> The eight American women were all uniform in height weight and build.<br /><br /> Does height matter ? Given a lot of athletes to choose from, probably. In a small group, No. Pride, training, and individual effort can not be measured with a ruler.<br /><br />If you take two groups of elite athletes with 1 group with a limit of 165 lbs, the other unlimited bodyweight, all with similar cardivascular performance, I doubt that maximum strength will be with the lightweights. <br /><br />The heavyweights, if bodyfat is equal, will have more available fat to burn at max cardio pace. The longer the endurance event, the more fat you burn, if you have it available. Even in a 6 minute race, you have a critical % of fat burning in the 2nd half of the race.<br /><br />On our erg in college, we calculated horsepower per pound. Who was top ?<br />There was a 3 way tie.<br /><br />220 lb 6'5" HWT 165 lb 5'9" LWT 145 lb 6'0" LWT<br /><br /> Fastest runners on the team ? The first and third guys listed above.<br /> Longest stroke ? The 3rd guy.<br /> Worst OTW Technique ? The HWT.<br /> Best OTW Technique ? Again, the 3rd guy.<br /><br /> If you train together, body weights can be in a range. Overly narrow not that important. But if not a narrow ranget, they need to be in the boat together for many months so the LWTs can acclimatize to a heavy boat, and learn how much power to use early. Throw a LWT in a HWT boat, and he needs to back off his power output, because proportionally, the boat is going to average 40lbs or more a person, sit deeper in the water. Short term, it does not work. We tried it in a non-competitve HWT 4 (avg wt 200 lbs, 1:48 500m) by bumping in a top performing LWT (150 lbs) to make a 3 HWT + 1 LWT Four, that could do 1:38 500m. In 2000 meter races the LWT helped them to big leads at 1000 m. But he was wasted at 1500 m, and the boat went from leading at 1000m to 6th place at 2000.<br /> <br />Same guy, 150 lb LWT tried some 1000m intervals with different HWTs (205 lb) in a pair. Extremely fast. The HWTs found it great fun to be so fast, and wanted to do it again. Again, the LWT was collapsed afterwards. He enjoyed the challenge. Even in a pair, the LWT was powerful enough to keep the boat straight, but the extra effort in a heavy boat was extremely taxing.<br /><br />Excellent rowing HWTs are very scary animals in terms of there raw power and endurance. Getting there is a lot of hard work over a long period. Tougher than being a great LWT. But in a small program, those big guys may need a smaller person to fill out the boat. A super LWT at 80% effort (to maintain endurance, and not burn out) might be more valuable than a less fit HWT at 100%. The HWTs benefit by having a lighter boat. The LWT has to train hard, but race carefully. He can kick in his reserve at the end of the race. Better then needing an IV the last 500 m.<br /> <br /> It comes down to pulling your weight to make the boat fast. A coach finds the best combination from the available personnel. Drooling over height of a lazy athlete is useless.<br /><br />I was that LWT in the cross boat experiments, 30 years ago. <br />

[old] Coach Gus · Post by **[old] Coach Gus** » November 21st, 2005, 1:32 am

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(ljwagner @ Nov 20 2005, 08:01 AM)</b></div></td></tr><tr><td class='quote'>On our erg in college, we calculated horsepower per pound. Who was top ?<br />There was a 3 way tie.<br /><br />220 lb 6'5" HWT 165 lb 5'9" LWT 145 lb 6'0" LWT<br /><br /> Fastest runners on the team ? The first and third guys listed above.<br /> Longest stroke ? The 3rd guy.<br /> Worst OTW Technique ? The HWT.<br /> Best OTW Technique ? Again, the 3rd guy.<br /><br /> [right] <br /> </td></tr></table><br /><br />What college and what year was this?

[old] tditmar · Post by **[old] tditmar** » November 21st, 2005, 7:44 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(afolpe @ Nov 16 2005, 01:41 PM)</b></div></td></tr><tr><td class='quote'>I don't row on water, and probably never will, so pardon me if this is obvious or ignorant. I was just wondering why rowing is handicapped by weight, rather than height. It seems like tall rowers have a significant advantage (for a given weight), whereas heavy rowers have no advantage at all (for a given height). I realize a heavier rower may be more muscular, but I would imagine the best LWT's are those people tall enough to be HWT, but disciplined or lucky enough to be able to make the weight cutoff.<br /><br />Enlighten me?<br /><br />Andrew <br /> </td></tr></table><br /><br /><br /><a href='http://www.umich.edu/~mvs330/w97/rowers/main.html' target='_blank'>http://www.umich.edu/~mvs330/w97/rowers ... tml</a><br /><br />We had several interesting results to address out initial question. First, we learned that the joints for a tall and short athlete go through different same angles during the rowing motion. These angle are essentially the same because of the nature of the exercise, so the difference was in the range of motion, which was greater for the shorter athlete. This showed the height difference did not inherently change the movement patterns for the athletes, the fundamentals are the same, but the actual distance covered changes (Lehmans 1987). Despite the greater range of motion in the shorter athlete, the taller athlete had a longer stroke by virtue of the longer body segments. <br /><br />Our results showed us that height does affect the stroke and power output. The effect of being taller and having longer limbs is that the handle must move a greater distance in the same amount of time in order to maintain the same stroke rating. Work is distance divided by time, therefore the given the same time interval and longer distance the handle travels, more work is generated by the taller athlete. We realized that the motions are the same and even though both athletes exerted force, the taller athlete could generate more force and do more work than the shorter athlete due to leverage of limb length. Our results helped to prove this by showing that the angles of movement were similar, but the speed and distance covered were greater in the taller athlete. Figures seven and eight were instrumental in showing how similar angles can have much different force and velocity outputs due to segment length. In order to maintain a similar stroke rating , the taller athlete must move the handle a greater distance in the same amount of time, generating more power and doing more work. This is consistent with a general assumption made in the rowing community. The taller rowers are placed in the middle of the boat where their power can be more efficiently harnessed. The shorter rowers are placed at the ends on the boats, bow and stern, because a shorter stroke has more finesse and control (Fisher). <br /><br />There were some limitations to this study however. The taller subject had a considerable experience advantage over the shorter athlete. This may have had an effect that could not be compensated for in this experiment. The next step would be to evaluate a tall and a short athlete who have the same experience level in order to try and eliminate as many outside factors as possible. <br /><br /><br /><br />

[old] John Rupp · Post by **[old] John Rupp** » November 21st, 2005, 7:53 pm

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(tditmar @ Nov 21 2005, 03:44 PM)</b></div></td></tr><tr><td class='quote'>The effect of being taller and having longer limbs is that the handle must move a greater distance in the same amount of time in order to maintain the same stroke rating.[right] </td></tr></table><br /><br />The effect of being not as tall is that the stroke rating must move to a greater number in the same amount of time in order to maintain the same distance of the handle.<br />

[old] ljwagner · Post by **[old] ljwagner** » November 22nd, 2005, 1:00 am

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(Coach Gus @ Nov 20 2005, 10:32 PM)</b></div></td></tr><tr><td class='quote'><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(ljwagner @ Nov 20 2005, 08:01 AM)</b></div></td></tr><tr><td class='quote'>On our erg in college, we calculated horsepower per pound. Who was top ?<br />There was a 3 way tie.<br /><br />220 lb 6'5" HWT 165 lb 5'9" LWT 145 lb 6'0" LWT<br /><br /> Fastest runners on the team ? The first and third guys listed above.<br /> Longest stroke ? The 3rd guy.<br /> Worst OTW Technique ? The HWT.<br /> Best OTW Technique ? Again, the 3rd guy.<br /><br /> [right] <br /> </td></tr></table><br /><br />What college and what year was this? <br /> </td></tr></table><br /><br />Why do you ask, Coach ? <br /><br />University of Santa Clara. I graduated in 1974.<br /><br />I think those erg scores were from late 1971, or early 1972.

[old] Coach Gus · Post by **[old] Coach Gus** » November 22nd, 2005, 2:01 am

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(ljwagner @ Nov 21 2005, 09:00 PM)</b></div></td></tr><tr><td class='quote'><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(Coach Gus @ Nov 20 2005, 10:32 PM)</b></div></td></tr><tr><td class='quote'><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(ljwagner @ Nov 20 2005, 08:01 AM)</b></div></td></tr><tr><td class='quote'>On our erg in college, we calculated horsepower per pound. Who was top ?<br />There was a 3 way tie.<br /><br />220 lb 6'5" HWT 165 lb 5'9" LWT 145 lb 6'0" LWT<br /><br /> Fastest runners on the team ? The first and third guys listed above.<br /> Longest stroke ? The 3rd guy.<br /> Worst OTW Technique ? The HWT.<br /> Best OTW Technique ? Again, the 3rd guy.<br /><br /> [right] <br /> </td></tr></table><br /><br />What college and what year was this? <br /> </td></tr></table><br /><br />Why do you ask, Coach ? <br /><br />University of Santa Clara. I graduated in 1974.<br /><br />I think those erg scores were from late 1971, or early 1972. <br /> </td></tr></table><br /><br />Just trying to get the facts sorted out. I was at SC during that time and don't remember the experiment. Who were the other two oarsmen? How did you figure hp? Are you the Wagner whose back was always hurt and always took a hot shower before trying to row? PM me if you don't want to continue the discussion on the forum.<br /><br />Also check this thread for more questions and comments about one of your other posts:<br /><br /><a href='http://concept2.ipbhost.com/index.php?s ... c=1399&hl=' target='_blank'>Other thread</a><br /><br />

[old] ancho · Post by **[old] ancho** » November 22nd, 2005, 8:50 am

<table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td><div class='genmed'><b>QUOTE(ljwagner @ Nov 20 2005, 05:01 PM)</b></div></td></tr><tr><td class='quote'>At the 1984 Olympics, the Romanian women won all the rowing events except the 8. They took silver, losing by about 2 feet. Those silver medalists all wore their MULTIPLE gold medals to the medal ceremony. I think one or two of them had 3. The US team rowed one person to one seat, no one rowed two races. The Romanians had about 8 woman and a spare, and raced all the events. <br /><br />...[right] <br /> </td></tr></table><br /><br />As you are mentioning '84 Olympics:<br />In LA, Spain won his (up to now) only olympic medal in rowing.<br />It was silver in the coxless pairs (which BTW was won by Romania):<br />On the Stroke, Fernando Climent, lightweight and flawless technique, 1983 world champion on the eight. <br />On the Bow, Luis Maria Lasúrtegui, heavyweight, 6th in 1983 with Jose Ramon Oyarzábal on the 2-.<br />(Rowing on one of those beautiful clear wooden Stämpfli)<br />I don't have the exact data, but there must have been about 15 cm difference in size and 20 kg in weight between them (in those times ).<br />Despite the huge differences, it was a joy to see these two row together!<br />So what matters?<br />Endurance, strength, technique and an extremely good working team. <br />And all this not always based on logical lab-data. <br />Easy, heh?

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Weight Vs Length

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