I guess I’ll just have to agree to disagree with that . I can fish out of my metal canoe with flat metal seats like folding chairs for 14 hours straight no problem. 2-3 hours in the super stable Jackson kayak with top of the line comfy seat that I can stand in is nearly crippling .
take the seat out and sit around the fire and it’s just fine
Also I don’t have physical fitness issues
its not being sore for days after, it’s while I’m in the kayak. As soon as I get out of it, all is better