Ergonomics is a science also known as Human Factors Engineering.
The problem is simple, and sooner or later practically any kayaker and kayak fisherman faces it: Spending long hours paddling and fishing in or on top of an ordinary kayak (sit-in or sit-on-top) inevitably causes some circulation problems and leg numbness, occasional cramps, pain in your lower back, and often fatigue and discomfort in your shoulders and neck.
In fact, kayaking is so closely associated with back pain that kayakers commonly appear in TV ads for back pain relief patches and drugs...
After you begin seeking information about your problem and advice on ways to solve it you realize that the only thing that really works is paddling back to shore, standing up and performing the exercises that physiotherapists recommend for kayakers.  In other words, there is no gear that you can outfit your ordinary kayak with that can provide an effective and long lasting solution to any of these symptoms simply because they occur as a result of you being seated in the L position - the traditional sitting position in kayaks.


The problem is caused by a combination of two things:
1.   Being seated in a non ergonomic position to start with, and
2.   Being unable to switch to any other position and release the stress that builds up in the critical pressure points in your body, especially in your legs and lower back.

Have you ever asked yourself why is it that the traditional, L kayaking position is used only in ordinary kayaks and in no other land, snow or water equipment?  The answer is that it's because although the L position is the worst for you it's simply the only one that ordinary kayaks can offer.

Double Trouble: The Combined Effect of Horizontal and Vertical Pressure on Your Lower Back:

Figure 1. Horizontal Pressure

Figure 1 on the left shows the horizontal pressure that your legs exert on your lower back in the traditional L position used in all ordinary kayaks including both sit-in (SIK) and sit-on-top (SOT). The pressure points in the lower back region can cause irritation and inflammation of the sciatic nerve (sciatica) felt as pain traveling from the lower region of your back down across your lower thigh. Foot braces and other support for your feet actually increase the horizontal pressure that your legs exert on your lower back. The back support and foot braces may hold you in your torso in place and prevent you from falling backwards or slipping downward, but they also limit your freedom of movement, increase pressure on your lower back, cause leg numbness and cramps and result in increased fatigue.

Native people of the Arctic circle who were the first to make and paddle kayaks used neither back rests nor foot braces simply because they were accustomed since infancy to sitting on the floor with their legs stretched forward, unlike us modern Westerners who lose this ability in early childhood when we learn to sit on chairs.

Figure 2. Vertical Pressure (Weight)

Figure 2 on the left shows the heavy vertical pressure (weight) applied on the lower part of your spine when you're seated in the traditional L kayaking position. The same sensitive area in your spine that's pressurized horizontally by your legs pushing on it is being pressurized even more by the combined weight of your torso and thighs, that is nearly all your body weight.  Your legs are prevented from supporting your body weight in this position. In addition, sitting in the L position without being able to change your body position increases your fatigue and discomfort, and reduces both performance and fun. Cushioning your seat doesn't really solve any of these problems since all it can do is spread the pressure from a single point to a wider area, but the combined pressure is still there and it keeps working on your lower back all the time. Sooner or later you feel very uncomfortable, and sometime it's too late since you've already been injured.

Kayaking in the L position with no adequate support for either back or feet is not a sensible solution for modern anglers and paddlers who have to spend hours kayaking and fishing from this low and uncomfortable position.

Food for thought: If you had to perform some hard work or other physical activity in any position of your choice, would you even consider doing it sitting with your legs stretched forward like this?  Do you fish or do you know anybody who fishes seated in this position from shore or from any other type of fishing boat?    -The answer is: ABSOLUTELY NOT!

More food for thought: Airplane coach seats are fairly comfortable - certainly more than regular kayak seats, but why is it that after some time most people feel uneasy sitting in them?  The answer is that the limited space makes it difficult for you to change positions, which leads to the buildup of discomfort and fatigue to a point where many people feel they must stand up and stretch, and those who can afford it promise themselves to fly first class next time - if only for the extra legroom.

Long term effects
Not all damages are felt immediately. Sometimes it takes years for the damage to accumulate, and by then it might be too late to fix it.  This is true for back and shoulder problems.

Read more about kayaking back pain and leg numbness


What do cross-country motorbikes, mountain bikes, horses, snowmobiles, all-terrain vehicles (ATV) and personal watercrafts (PWC) have in common? It's the Riding Position.  
And what do skiing, surfing, water skiing, dog sledding, snowboarding, windsurfing, skating and skateboarding have in common? -The Standing Position.  
It's simply because the Riding and Standing positions are the best for you in both ergonomic and biomechanical terms, which means they offer best control and more power, and result in less fatigue and injuries.
When we need to make long efforts during motion we have more available power and better control standing or sitting with our legs lower than our upper body (biomechanical advantage), and we also feel more comfortable and less tired this way (ergonomic advantage).
 

The new, patented W Kayak re-distributes buoyancy from the boat's longitudinal axis to its two sides and thus offers maximal support to the kayak fisherman's balancing, control, steering, propulsion and fishing efforts.
The central part of the W Kayak- it's 'backbone', which joins the two hulls has the shape of a long, 14" high saddle.  The kayakers can move back and forth on the saddle according to their need (e.g. surfing, taking out etc.) and he can also switch anytime between numerous ergonomic positions:

Your kayak's cockpit has other functions besides protecting you and offering you optimal comfort:
It is also a workplace in which you store your gear and handle it.
In W kayaks all the gear you need is within arm's reach, and there's no chance of it going overboard since in case it slips out of your hand it would end at the bottom of one of the hulls, where it will be easy for you to find and reach it.