Question
I cant afford a personal chiropractor but would like some general advice from you if possible-

do you recommend keeping your back straight in general?  for most activities?

(one specific example I want to know too would be wieghted sit-ups...back straight?)
and most importantly...is straightening your back really important for weight lifting...because I dont know if I should straighten it all the time because..

also-it seems like I start feeling sick normally when I try to keep correct posture...and I really associate the sickness with that...what could that Possibly mean?  am  I doing a placebo effect of sickness or is there some other possible way toxins are entering my body when Im straightening my back for long perionds of time?  I associate it with a sort of OCD means of getting literally physically a little ill.  

Answer
Jeff,

Thank you for your questions!  There have been a number of ideas on maintaining srtaight upright posture and it seems everyone has a different idea.  The latest research has shown when you are sitting as in classes, church, movies etc. for a longer period of time, it is not neccessarly good to maintain a constant upright posture.  Studies have shown that it is best to move around in your seat.  Changing your posture help lymphatics move, relieves static posture stresses on the back and neck, hydrates the disc and more.

To answer your question about a straight back during weighted sit-ups, straight is not neccessarily good.  First I would suggest that you not do weighted situps.  A traditional situp alone puts stresses on the spine that are deemed harmful.  Adding weight is obviously not beneficial to the spine.  To really tone the abdominal section try doing a situp but stop when you get the shoulder blades off the ground.  Hold it at that point for 5-10 seconds.  At the same time take a deep controlled breath that expands your abdominal area.  This will not only help tone and define you abs, but will offer much imporved core stability and lessen the chances for back pain during exercises.

If you are set on your weighted situps then you should focus on maintaing your bodies natural curves to distribute the forces sustaind during exercise.  Your area (thoracics) that is in the mid back, between you shoulder blades should be rounded in the back (convex in the back).  Your neck and low back should have a nice dip or concavity in them.  The easiest way to maintain this posture is to place the hands not behind the head but behind the neck, with your fingers laced, and let your head rest back on your hands.  Keep you neck out of the situp.  Also don't flatten your low back, but allow it to have a curve.  This will ensure a better chance to distribute weight.

Give the other situps I described a try and when you breath in flex the abdominal muscles and expand them to draw in air. THESE REALLY WORK!!; and best of all they are much safer on the spine.

I hope this has helped you!

Dr. Wiggins