Great Advice
This is great advice and a great perspective. It seems like finding the right Kayak is more difficult than anything else I have looked at buying.
Something better???
There are too many variables for a one single answer here… BUT… at the risk of starting that age old argument… and IF you’re back problems are “lower back” pain… a canoe IS an option to relieve some types of back pain… and yes you can achieve equal enjoyment from the proper hull 
What does your physician say?
Halfpaddle’s point is a realistic one:
Many kayakers don’t understand that sitting on the floor with your legs forward and your lower back being pressed backwards can create uneasiness, leg numbness, back pains and even back injuries in the long run.
You may want to consult a physiotherapist or a physician that are experienced in this type of problems before taking a decision.
No sport is good for everybody - kayaking included.
QCC 700 or 600
Let me try this once again. I had a ruptured lower disk that had surgery. It was OK at first but finally got to the point that the pain was so bad that I have been at near constant bedrest for 4 years. I am a slim 6’ 175# but am losing weight to make it as easy on my back as possible. I had always been active and in good shape but this past 4 years has left me weak. I mainly want the Kayak for exercise and to get out of the house. I live on a lake 25 mi x 5 mi. I would keep the Kayak at the dock.
I have heard so many good things about the Q700 that I decided to check out their website. The carbon 700 is only 41# and the 600 38#. Because of my weakened state I need the most efficient design that will go the farthest with the least thrust.
It seems many here prefer the 700 with rudder. There is a great sale going on through today. I would need my knees up as high as possible to take the strain off my back.
It sounds like they custom make the Kayaks. Would this be the best option for me?
As usual, thank you very, very much.
Q700
– Last Updated: May-31-04 9:59 PM EST –
After that much time in bed - I'd be concerned about a taking measured approach (of course you will). If you work up slowly, I'd think paddling could be a good way to restrore core strength. Done wrong - back in bed. You know your condition more than we.
Don't know your experience level/balance/water time, but maybe given the severity - a more stable platform (used) and then move up as ability restores? Q700 is remarkable stability for a 21" beam, but it IS a 21" beam.
The Q700 would be my pick between the 600/700. Rudder or skeg is up to you.
Love mine more every paddle. and an very nice balance between tracking and maneuverability. Super efficient cruiser.
Lot's of Q700 owners here! A real bonus if you get one and want suggestions on optimizing the comfort as you'll get several options/opinions on almost anything.
The other bonus - 30 day test paddle and awesome return policy. No boat's perfect - or all things to all paddlers - but the Q700 is a great boat.
If you are leaving it at the dock
you may be ok with a plastic SOT or even a surf ski. Gives you lots of positions and excellent back support with various backbands. Buying a boat you are not comfortable in makes little sense, no matter how well made it is. Nice boats are susceptable to theft also. Go to a demo day and try lots of different boats. Ask other paddlers to try theirs.
Wilderness Systems Phase 3
My wife and I have Wilderness Systems Pungo kayaks with the newer Phase 3 seats. These seats come in other models too, depending on your needs. The seats are VERY comfortable and adjustable. They’re the only kayaks we’ve spent much time in, but a very experienced kayaking buddy tried them out and declared them to be the most comfortable seats he’s ever paddled in.
Are you sure ??
The type of back injury and problem you are experiencing strongly suggests the sitting position of a kayak with your knees up will cause more pain, not less. Have you tried paddling a kayak to see how it feels on your back?..goodluck …kim
A Kevlar canoe?