With your spine in align, you will become a more efficient paddler.
When we study the act of paddling a kayak from a posture perspective, one thing is abundantly clear: everything just works better when you are sitting up straight. If the body had its way, we would always be sitting or standing with our spine in a nice, comfortable, vertical position. This is your body's action position. When you are slouched back, your strokes can't be done efficiently. Remember, whatever stroke you are doing requires torso rotation. When your spine is in align, as I like to say, it is easier on your skeletal frame.
Why do some paddlers like to slouch? The main reasons are fairly straightforward: the muscles used to maintain erect posture are out of tone, or their seat backs don't give them the proper support to maintain that position. Many times, it is a combination of both. Some paddlers with lazy muscles slouch even when they have good back support, which bends their back unnaturally over the seat back/band. If you have a tendency to slough, it is time to work on those neglected back and stomach muscles. Stretching poses, including forward, back, and sideways bending, are the way to revive and tone those forgetful muscles. Stretches that are good for the hips are helpful for sitting in the kayaking position. Your body is more than willing to serve you well; it is up to you to keep it in good working order.
Good support from your seat back/band will make you more likely to sit up straight. If you have a one-piece seat that slopes back, it will be necessary to pad it out so that it will support you upright. You can attach an inflatable back pad, glue in some closed-cell foam, or use a combination of the two for this. If you have an uncomfortable adjustable seat that tilts back and forth, usually adjusted with a rope and cleat, you can try the above remedies also. If these do not work, you may want to remove the seat back and attach a back band. These come in various shapes, sizes, and attachment methods. They all require bolting to the flange that connects your seat to the coaming, or sometimes to the bolt holes through your deck that bolt your seat in place.
In any case, you want to get good, firm support in your lumbar area so that you can maintain your upright posture with the least amount of effort. Back bands that feature ratchet systems allow you to crank them up into your back, or release them. These are the most easily adjustable. A solid plastic attachment strap helps keep the band in place, but you will probably need to add some support so it stays in place when you get in/out. Look at the outfitting on new boats for some good ideas.
Another aspect that may cause you pain is the angle of your legs. Is your deck so low that you can't bend or raise your knees? This can cause thigh and back pain. You want your knees bent. This gives you a stronger, more natural grip on the deck. It makes it easier to lean/tilt/edge the kayak when bracing and turning. If the deck is too high, you can add foam to the thigh braces. If you don't have any, you can usually shape some out of foam.
If your legs splay out too far to the side, this will cause you some hip pain. You can add foam to the side of the kayak to keep your knees from flopping out too far; just remember to leave enough room between that and your thigh braces to get your knees in and out safely. There are also thigh risers available that fit in front of the seat to rest your thighs on, giving more support to your raised legs. Outfitting your boat will make it a joy to spend time in, and prepping your body with stretching will make your whole life more enjoyable. Spend some time at both, and reap the benefits.
Contributing editor John Meyer is a co-owner of and head sea-kayak instructor at the Northwest Outdoor Center in Seattle.