Date:         Tue, 10 May 1994 10:58:07 -0700
From:         Linda Lamb <lamb@ORA.COM>
Subject:      Why some injured and some not

Ideas from Repetitive Strain Injury, by Emil Pascarelli & Deborah
Quilter (John Wiley & Sons, $14.95):

Risks for RSI include:

- First, your typing style (if/how you rest, lean; hitting or
  pressing keys harder than needed; keeping thumb or pinkie
  extended; not curving fingers; gripping a mouse; or typing
  while cradling phone between shoulder and neck)

- Next, your posture.  (If that's out of whack, your muscles
  strain to keep you in position.  Must be why Feldenkrais
  and Chi Gung/Qi Kong work for so many people.  The musculo-skeletal
  habits that haven't worked for a lifetime can be relearned;
  these practices are also great for promoting body awareness.)

- Your job.  How much typing; how much rest time allowed; amount
  of control you have over your work.

- Stresses in your workspace such as noise, crowding, ventilation,
  air quality, light, having to move from workstation to
  workstation.

- Your genetic makeup:

  * Bone structure, tendency to arthritus, diabetes, thyroid
    disease (which might predispose you to RSI).

  * Double-jointedness.  "A very common, but mostly overlooked,
    predisposing factor for RSI is hypermobility of the finger
    joints....  Instead of holding firm when a key is struck,
    the finger joint collapses.  This causes the wrists to
    bounce up and down.  It may sound minor, but if the wrist
    bends thousands of times a day, the tendons in the fingers,
    wrist, and forearm are strained.
      "Some people try to compensate for this tendency to
    collaps by contracting the two muscel groups that bend and
    straighten the fingers at the same time.  This
    'co-contraction' exhausts the muscles."  (Repetitive Strain
    Injury)

    (I was quite interested in this possible factor, since my
    thumbs are double-jointed, and my RSI is in my thumbs; also
    since I haven't seen this factor mentioned elsewhere.  This
    factor also fits with the idea that one reason women are more
    prone to RSI than men is that women are more flexible.)

  * Obesity.  Obese people need to hold their hands with more
    ulnar deviation at the keyboard.  (Also, obese people put
    more strain on muscles to hold weight of arms, etc.  In
    our office while doing safety inspections, I have also noticed
    that obese people typically get much less support from their
    chair--they're just too large for standard equipment.)

  * Slender builds.  (Smaller muscles tire and get injured more
    easily than large muscles.  Sounds like you can't win--obese
    or slender.)

  * Age.  (Older people more prone to RSI.  Could be how long
    have been on the job, or the natural elasticity of bodies wearing
    down.)

  * Sex.  This book mentions differences as being that women have
    smaller muscles than men (on average); that women's hormonal
    changes can cause swelling; and that women's jobs are more
    frequently ones that require continuous, machine-paced input.

    (I have also read in other sources that women are more apt than
    men to get RSI because their muscles/tendons are more flexible
    and will more easily stretch out further than soft tissues
    should.  I have a theory that another contributing reason that
    more women than men are prone to these overuse injuries, is that
    women tend to perform more fine-motor activities in the rest of
    their lives, such as sewing, knitting, gardening, cooking,
    crafts, etc.)

  * Long fingernails (which prevent you from curving fingers).

  * Diseases like alcoholism, arthritis, gout, kidney disease,
    thyroid disease, high-blood pressure.  Pregnancy.

  * Drugs which cause water retention, such as birth control pills,
    blood pressure medication, anti-inflammatories.

- Attitude.  Refusing to acknowledge pain, trying to tough it out,
  internal drive to excel, shyness (not wanting to ask for help
  from employer or doctor).

  (The ergonomics consultant who comes to our office -- Lynn Oberlander
  in Forest Knolls CA, who I would recommend especially for her focus
  on passing on knowledge to people at the worksite, 415-488-9070 --
  says that often the people who are most at risk for RSI are the
  "best workers":  those who work overtime, push themselves, ignore
  their bodies.)

- Stress that you aren't able to control.  (Stress itself is
  not bad; it's part and parcel of life.  Relaxation techniques
  become important, since they help you control your response
  to stress.)

- Lifestyle choices, such as fatigue (not sleeping, not resting),
  diet, caffeine, alcohol, recreational drugs, smoking,
  sedentary behavior.  (These inhibit good sleep, interfere with
  circulation, keep you out of touch with your body.)

- Exacerbating activities:  video games, driving, carpentry,
  gardening, needlework, musical instruments.

By the way, I recommend Repetitive Stress Injury as a book for
those recovering from RSI.  It is written from the computer user's
viewpoint; it is practical and realistic.


--
Linda Lamb, lamb@ora.com