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Seat dump: balance vs posture

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    Seat dump: balance vs posture

    Interested to hear from other Para's (or quad's with decent core muscle control) how much dump (difference between fsh and rsh) you prefer in your chair.

    I hear a lot of people say that you're supposed to sit 'in' your chair, not 'on' it, but the more dump I have the more slouched I am. I currently have 1.5" or 2" (can't remember and haven't measured). I definitely feel comfortable but want to find a way to sit up straighter without feeling like I'm going to fall out. Anyone have suggestions?

    Ps. I have moderate core muscles (good at wheelies, going off curbs, general balancing) but definitely can't do sit-ups, wheelie down a flight of stairs or fly off curbs like Toto
    "What is the first business of one who studies... To part with self conceit. For it is impossible for anyone to begin to learn what he thinks he already knows." -Epictetus (55-135) Greek Philosopher

    #2
    i run 2 1/2" dump, any more makes me uncomfortable and start to have spasms.

    Comment


      #3
      I like 3" of dump with a 12" backrest. 14" if it's an ADI rigid back. I don't need dump for stability, I'm an ASIA B (nearly a C) T12 para, with sacral sparing. But, it's what is most comfortable to me. 2.5" is OK, but 2" or less doesn't feel very good, at all. I have a fusion from T10 to L3 and my muscles around there aren't used like they would be if I had no Ti in my back so I like to lean back a bit to help my sitting endurance. With less dump, though stable, I get sore in the lower back much quicker.

      Also, keep in mind backrest angle and seat to footrest usually need to be adjusted when you change dump.
      "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

      "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

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        #4
        You might try changing the back angle to make you sit up straighter. Be aware that you may feel really unstable when you first change, but a few hours will make a big difference.
        Don - Grad Student Emeritus
        T3 ASIA A 27 years post injury

        Comment


          #5
          I just took part in a wheelchair seating study, where a seating "expert" adjusted my chair. Prior to this I would adjust my chair, for comfort. For some reason I was all about making my seat have the least amount of dump and I ended up with 3 degrees (1" with an 18" deep cushion) for dump. My back was set so that I could raise both my hands out in front of me without falling forward, add an empty glass to my hands and I'd topple forward.

          After chatting with the "expert", their goal seemed to be to have the seat back at the vertical, 90 degrees to the floor. Then depending on the individual adjust the seat dump so that the spine is in the correct alignment.
          Then when I put my hands out in front of me I fall forward, to be honest this irritated me so I backed off the back a little so I can just about put my hands straight in front of me without toppling.

          I ended up with 8 degrees of dump (2.5"s with an 18" deep cushion)

          I was more comfortable before, but apparently my spine is correctly aligned now, and everyone says I've lost weight !!! it's made me look thinner.

          So my 2 cents is get someone who knows how to check your spine is correctly aligned and figure your seat dump from there.

          Comment


            #6
            Like NW says, object is to have a 90 to 92o back angle. Dump depends on level of injury. Lower breaks use less dump, higher more dump. I'm T'6/7 and have a 4' dump with 92o back. My buddy is a strong T/12 and uses a 1" WITH 90o back.

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              #7
              I'll look up my specs and find my dump ok ? I know I Need to do wheelies to get over certain things in my area


              I know mine is not 90 degrees on back plus my back is 18 inches high because of my neck surgery .
              I'll look into the tech stuff later today as I love this type of helpful ideas etc... I'd measure mine now but I left it in the back of the truck to do some food shopping I know I have 5 degrees camber .

              See yaaa all
              Sincerely GL

              Comment


                #8
                This is why it's important to get an adjustable chair before going non-adjustable. A person must tweak a chair to get it just right. Some like different settings even though they may be the same level of injury.

                Comment


                  #9
                  Patrick Madsen
                  Sooo true That is funny how you just mentioned about adjusting
                  about a year ago I took my wheelchair all apart and adjusted it to my personal preference I build motorcycles and had my wheelchair in the shop one day so
                  I tore it all apart lol now it is set to my liking
                  Now it works like a breeze

                  Comment


                    #10
                    Originally posted by Covathalis View Post
                    I currently have 1.5" or 2" (can't remember and haven't measured). I definitely feel comfortable but want to find a way to sit up straighter without feeling like I'm going to fall out. Anyone have suggestions?

                    Ps. I have moderate core muscles (good at wheelies, going off curbs, general balancing) but definitely can't do sit-ups, wheelie down a flight of stairs or fly off curbs like Toto

                    the most efficient dump for paras with abs is somewhere between 2" and 3", a chair with less is not stable, you could be pitched out of it very easy downhills, but there are others factors that influence like the cog and backrest.

                    I`ve got 2.76" dump with 3.34" cog and 10.62" backrest at 90ยบ.

                    Of course i`m speaking about active chairs for active guys, you could be seating in your house with 0" dump without any problem.
                    Last edited by totoL1; 10 Apr 2011, 1:39 PM.

                    Comment


                      #11
                      Thanks guys.
                      "What is the first business of one who studies... To part with self conceit. For it is impossible for anyone to begin to learn what he thinks he already knows." -Epictetus (55-135) Greek Philosopher

                      Comment


                        #12
                        I'm a t-4 complete about 6'3" and I use the carbon-fiber jetstream. I have it set pretty low on my TiLite ZRA. I wanted to switch to the upholstery backrest, but when I tried it I slouched a good bit and didn't feel like it would be good for my posture long-term.
                        Donnie: Dr. Xiao, What are your thoughts on a cure/combination therapy for SCI's??
                        CG Xiao: Donnie, I don't want to disappoint you, but I think it is impossible to restore the continuity of the cord or "bridge the gap" in the near future, let's say: 50 years. Dr Wise Young has been my most respected scientist in SCI. He has dedicated and contributed to SCI no other can match.

                        Comment


                          #13
                          Oh, and I ride about 1.5" of DuMp.. Sometimes i'll leave a dump back there...
                          Donnie: Dr. Xiao, What are your thoughts on a cure/combination therapy for SCI's??
                          CG Xiao: Donnie, I don't want to disappoint you, but I think it is impossible to restore the continuity of the cord or "bridge the gap" in the near future, let's say: 50 years. Dr Wise Young has been my most respected scientist in SCI. He has dedicated and contributed to SCI no other can match.

                          Comment


                            #14
                            This issue is really confusing for me.
                            to explain.... I have been having shoulder problems, a rotator cuff, tear in one of the tendons, and my physiotherapist says that I slouch in my chair and my posture is contributing to my shoulder problem.
                            i am getting a new back for my chair, a J3. I currently have a soft upholstered /velcro back.
                            Anyway, I wonder about the dump on my chair, I actually don't know what degree it is. I have a rigid titanium frame. How do I measure it?

                            Comment


                              #15
                              Originally posted by partygirl View Post
                              Anyway, I wonder about the dump on my chair, I actually don't know what degree it is. I have a rigid titanium frame. How do I measure it?

                              Measure from the floor to the underside of your cushion at the front and then from the floor to the underside of your cushion at the back of your cushion.

                              You should have two measurements.

                              Subtract the measurement you took from the back of the cushion from the measurement you took from the front of the cushion, this is your dump.

                              For the angle you need the length of your cushion

                              Then your angle = sin−1 (dump/length of your cushion)


                              Divide the dump by the cushion length. for example I have an 18" long cushion and have 2" of dump, so that gives me 0.111111

                              Then take that number and put it in here
                              http://www.rapidtables.com/calc/math...Calculator.htm

                              Hit the equals (=) sign and it'll give you your angle.

                              For my example I put in 0.11111 and get 6.3787296225541.
                              So I have 6 degrees of dump.

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