Friday, July 31, 2009

The L Kayak Posture and Back Pain

The traditional L posture that both sit-in and SOT kayaks offer to paddlers and fishermen is different from the original Inuit kayak posture by the fact that native people of the arctic regions built their kayaks with neither backrest (lumbar support) nor footrests.
Backrest and footrests were introduced by modern times kayak makers in order to keep the paddlers and fishermen who use kayaks from sliding forward, but the price these kayakers and kayak fishermen have to pay is discomfort that leads to back pain, leg pain, leg numbness and other problems.
The combination of footrests and backrest provides your legs with a frame against which they can push in order to keep you from sliding forward. Your legs have the most powerful set of muscles in your body, and when they push against the backrest it pushes back - This is simple Newtonian Physics, and it creates a serious ergonomic problem for you, because your spine takes the brunt of this pressure, and it is a very sensitive organ.
In other words, this position known as the L posture because your legs are stretched forward, is unnatural to your body, as well as potentially harmful:
Basically, your spine is made from hard bones separated by discs of softer cartilage. This structure is best for supporting vertical loads and efforts typical to running, walking and standing up, but not for resisting horizontal pressure.
The above image illustrates how this works: Your own legs work must work against your back to support you in this posture while you're paddling and fishing.
Worst of all: You can't switch to another position because this one is the only position that sit-in and SOT kayaks offer.
As much as designers and manufacturers have tried to solve this problem by cushioning their kayak seats, it is impossible to solve the problems caused by this flawed design this way because your spine in your lower back is the only hard object between your pelvis and your rib cage, and that's exactly where the pressure is focused.

Another problem created by the L kayak posture is the vertical pressure on your tailbone and butt, as can be seen in this image:

The combined weight of your upper body with some weight of your thighs is pressing your posterior down, right in the area where your sciatic nerve is located.
Here again, your legs can't support this effort, but on the contrary - they are made tom play a role that aggravates the problem.
This constant pressure causes disruptions in the normal blood circulation to your legs, often felt as leg numbness and leg pain.
It can also harm your lower back, as your legs push harder in vain, trying to change their position and relive the the pressure on the sciatic nerve.

As you can see, this explains why so many people who use kayaks for touring and for fishing feel uncomfortable in their kayaks, and why a considerable number of them suffers from back pain and even back injuries.
Needless to say, that paddling and fishing in this position leads to premature fatigue.

1 comment:

Carl1971 said...

This is the problem