Elite Rowing Coach Blog

  • A bent oar, good or bad?

    When we see it we marvel about it:

    1. Why does the oar bend?

    When a rower applies power against the footboard and engages the body in moving the boat, the oar bends, because the force of the oarlock pushes in opposing direction to the force on the handle and the force on the blade.  This bending is similar to a bow, where the hand holding the bow works like the oarlock.

    2. Choosing oar stiffness

    As rowers, we have the choice what type of stiffness we want our oars to have.  It is not unusual to hear around the regatta course that a softer shaft is gentler on the body, because the oar is then more forgiving at the catch.... Forgiving at the catch? I won't answer this question in this blog post, but that type of reasoning makes me wonder about coaching logic.  Oddly enough, the oar bends the most in the most powerful part of the rowing stroke, half way down the leg drive, which also happens to be the most powerful body position in the rowing stroke.....  This begs the question: Why do we need the oar to bend the most when the rower's body can actually handle the resistance easily at that drive angle...  I will leave this last statement up to you to discuss amongst yourselves. Needless to say, oar stiffness has been on my mind since I competed at the world championships and Olympics.

    3. Choosing blade size

    From tulips, to hatchets, to smoothies, and Fat2 blades.....  Clearly, if the shaft is longer, then the blade can be smaller at the other end and the reverse is true, the shorter the shaft, the larger the blade size.  It is crucial to fit rowers with the right oar length.  Tall rowers, can handle longer oars because their overall stroke length and CATCH ANGLE....  Shorter rowers can not achieve the same catch angle with such "longer oars".  Therefore shorter rowers should be fitted with shorter oars.  As mentioned a couple sentences earlier, blade size becomes an important factor in fitting rowers with the right oar length and blade size.

    4. Rigging

    Rigging is a highly underused tool for competitive rowing. Think about it, for the last 100 years, we may have moved the oarlocks at most 5 centimeters on either side of each rigger. The most drastic change is oar length and blade size.....  Oar manufacturers and scientist are toying with oar length and shaft width and they are right to do so.  Just because a rower has the world record on the ergometer, that should not make you jump to the conclusion that the rigging used my such a beast is "hard".  Rigging an eight or a sculling boat depends on the size of EACH rower.  Once size does not fit all, and that includes team boats! 

    5. But really, should an oar bend or not?!

    If an oar bends, does it move the boat?  Answer: no.  Counter argument, the oar flexes at first and then straightens out....  The problem is that it straightens out because the tension can not be maintained by the rower....  So then, the oar straightens out at the end of the stroke, which leaves the smallest muscle groups of the body to deal with oar's de-flexing... at a point of the stroke where most rowers tend to allow the exit the blade from the water...  

    I help rowers and crews choose their oars.  I hope you enjoyed this blog post and that it motivates you to think about which oar size may work better for you and your team.  Good luck with winter training.  Xeno 949-400-7630; email: xeno@xenocoach.com

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  • Comments on this post (4 comments)

    • Brock Laschowski says...

      For a comprehensive [scientific] explanation to the question posed in this blog, please see the article entitled “The effects of oar-shaft stiffness and length on rowing biomechanics” published in the Journal of Sports Engineering and Technology [http://pip.sagepub.com/content/early/2015/05/05/1754337115582121?papetoc]

      On June 30, 2015

    • David Harralson says...

      This is an interesting question. From structural mechanics, stiffer is almost always superior to a flexing structure.

      The history of shell construction has gone in the direction from a more flexible structure to a stiffer structure. Primarily, this is because of material considerations.. The wood boat was not as stiff as a fiberglass boat, which was not as stiff as a carbon fiber boat. Wing riggers stiffen the hull structure even more. Each of these stiffer construction methods has led to faster boats because the rowers energy gets transferred more efficiently to the oar blade.

      The same is often true with respect with respect to oar construction.

      My coach will restrict the youngest junior rowers to smaller, more flexible oars since he feels that their youthful bone and muscular capabilities are more prone to prone to injury with the stiffer, bigger blades. Older and stronger rowers row with those blades they or the coach feel the best.

      We row the pair together. When we got new SmartOars, I ordered virtually the largest blades and stiffest shafts available, even though we are lightweights and I am now 75. In back to back tests, we are faster with these stiffer shafts.

      One thing to consider is that if a shaft bends, it stores energy, which it releases back into the system at a later time. However, this energy release is not 100% efficient, and the rower usually cannot control when this energy gets released. This creates what I call “vibrations”, which dissipate energy imparted by the rower and slow the boat.

      If the rower feels their force profile is not optimum, they can train it using the force display on the RowPerfect or an on-water instrumented oar lock.

      Finally, in a theoretical sense, a different stiffness between stroke side and bow side can lead to faster boat speed as the different stiffness can provide a more nearly optimum force profile for the stroke side and bow side rower. However, I rather doubt that you could find a meaningful improvement and have not seen any studies on this issue.

      On June 17, 2015

    • Ansgar John says...

      If it is an eight and the team is using the same oars and 7 out of 8 are bending… Then the 8th should bend as well ;)

      On March 20, 2014

    • anonymous says...

      Xeno, I understand what you are saying—as the oar bends, it is not moving the boat. However, the benefit is precisely what you state to be a downfall. At the end of the stroke the oar will straighten out again, as you correctly say, at the arms portion of the stroke. While the arms are the weakest muscles in the rowing stroke, they do not need to “deal with the oar’s de-flexing.” The force the rower puts into the oar through the middle of the stroke, which was ‘lost’ to the bending of the oar, will be returned at the end of the stroke with minimal effort. All the rower needs to do is hold the blade in the water and he or she will receive nearly 100% return on their efforts.

      Oars can, of course, be too flexible for the rowers. My conclusion: bend is good—to a point.

      On October 27, 2013

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