Life’s too short to paddle the wrong
kayak…
you need something for a grown up, you just haven’t found it yet. As you are figuring out, smaller kayaks may have the wrong proportions for adult bodies.
One of the fastest kayakers I have ever seen (and she holds a course record locally on a river race) is also one of these people who looks like a normal petite person and yet she is using a kayak longer than mine. And a much shorter paddle. The trick to her speed (besides her technique) is her long, narrow kayak FITS her, I could never fit that particular model comfortably, because I’m just wider in the hip and shoulder and I need a seat that works for people who need… a seat. And mine has a seat. It is not a space you are expected to cope with, but a seat shaped for humans. I sat in this one I have now in the kayak shop for a very long time (bless the sales person, who understood exactly what I was doing) making sure this seat was similar to the one I got along with well already, and that there was not going to be discomfort. Then they gave me a very adjustable instant seat you put in it that I can adjust further, and between that and the very adjustable foot pegs, I can fine- tune this so nothing goes numb.
Okay, so other people go faster, at least I can stand up and walk when I’m done !
Another thing to consider is the paddle… you may not be using the best paddle length for you and the model kayak you have. You also are supposed to be pushing with the hand on the side out of the water, not pulling with the hand on the side in the water. And you need to think about what your legs are doing because you need to be using them and your feet. Feet being cramped for space is a disaster in a kayak. You cannot alternate pushing against the foot pegs with each stroke for power, when you are stuffed into a kayak cockpit too tight.
When I want to go a bit faster, I will put the pool noodle segment under my bad knee so I am not tempted to push too hard and straighten that leg out too far while in the excitement of the moment. I also bring the foot pegs up a bit to give a little more bend in the knee, and pull the seat straps up a little so I’m a little more upright. Sometimes I will put more pool noodle behind the seat.
I do a LOT of exercises to strengthen my “core” and flexibility and balance, I have for my age/demographic way above average core strength compared to a non-kayaker, but it doesn’t mean anything and won’t be worth a 5¢ plugged nickel if the shape/angle of my kayak seat is crap, or too low, my foot pegs are all wrong, and my feet don’t fit. I don’t know if you bicycle, but it is the exact same thing- the seat needs to be at “your” special height, at “your” angle (near level, but sometimes a few degrees up or down), put on the post at “your position” relative to forwards/backwards, and shaped “for you” and you can go miles. Or you can go a few blocks on the wrong bike seat adjustment, and be wondering just Why Would Anyone Want To Do This Horrible Torture More Than 10 Minutes.
I actually bought a bike on clearance a few years ago, because it had the cheap seat from Hades, and I was sure that once it got replaced by something made for humans, the rest of the bike should work out. It did. It was a very odd thing to sit on something and notice immediately that everything else seemed to be “just so” size wise for proportions, other than the original seat was a piece of junk. But it is the same principle for biking and kayaking: you are suspended in a position in space that allows you to efficiently and very easily alternate pushing with each leg and foot, without unduly torquing your back and muscles over the hip.
Wrong
The OPer appears not to be a young person. Certain positions get harder to manage as you get older because muscles literally shorten up from not being asked to stretch. Your response reveals your age (again) and ignores what many people have to go through to stay active as they get older. It is more work.
but if the problem is technique
then stretching is at best a temporary fix.
1. Core fitness
2. Form and Posture
3. stretching
I'm convinced that with chronic back pain or injury, one has to do all three for the rest of their life. It sucks, but I think it's reality. Achieving fitness after becoming sedentary or unfit is a real struggle with a back injury.
Foot pegs
My lower back was really hurting, and someone asked if I was pushing too hard on my footpegs. Got me to thinking and I moved them back just a tad and that really made the difference for me. My boat just went from an 9 to a 9 1/2. Funny how improving my position made my boat better. I know, I know, the boat was great all along, just pilot error on my part.
Not going to happen w/o stretching
My point was that without some amount of stretching work, many people can’t achieve anything resembling a good position. You have to get as close as possible before going to alternatives to a decent position.
I get the harder to stretch part. Right now a static brace is not a happening thing for me until I have more time to work around a lower back that wants to be stiffer than it used to.