Tuesday, October 12, 2010

How Does Pedaling a Fishing Kayak Affect Your Back, Legs, Feet, etc.

A new, recently published article offers a remarkable insight on pedal driven fishing kayaks.It discusses practically every issue related to pedal drives, from every angle, including Ergonomics, Mechanics, Hydrodynamics and Real Life Performance.
This blog is interested in the ergonomic and bio-mechanical aspects of kayak fishing, and here are the findings on these subjects (quote):

Pedaling Kayaks’ Ergonomics - How Does It Feel To Operate a Pedal Driven Kayak?
The first and main argument in favor of pedaling kayaks instead of paddling them, is that our legs are far more powerful than our arms are, and therefore it makes more sense to use our legs for difficult tasks such as propulsion, rather than using our arms.
While being generally true, this argument is not necessarily applicable to the propulsion of kayaks. This is because although our legs have the biggest and most powerful muscles in our body, and are best fit for hard, long lasting efforts, using them for propelling any vehicle must be done under certain conditions, which are dictated by our own built, and ability to endure certain types of effort -
Limbs that have bigger muscles are comparable to engines with bigger cylinders – They can burn more fuel, and thus generate more power. The legs of a kayaker pedaling their pedal driven kayak generate considerable force, and this force is transmitted from their body to their kayak through three points:
1. The kayaker’s two feet, which the kayaker’s legs push forward, against the pedals, and -
2. The kayaker’s lumbar spine and lower back, that the legs push backward, compressing them against the backrest of the kayak’s seat, so as to provide support for the legs’ pushing effort in the opposite direction.
The force each leg applies on a pedal when pushing it is equal to the force the leg applies on the kayaker’s lower back. With two legs pushing two pedals, the force the kayaker’s legs apply the the kayaker’s lumbar spine is double the force needed to move each pedal, and here lies a big ergonomic problem.
Pedaling in the L position (recumbent) is essentially different from pedaling in the upright position (e.g. biking). The difference being that in biking, our legs push against our own body weight, and its that weight which supports the legs’ downward push against the pedals, and allows them to move. Recumbent bicycles have been known to exist since the 19th century, but upright (riding) bicycles outnumber them at a ratio of more than a thousand to one, simply because recumbent bikes are harder to use, meaning that they present serious ergonomic issues that upright bikes don’t.
Pedaling common kayaks is done in the L position, which is similar to the recumbent position. The L position is kayaks is known to cause a variety of back problems starting from premature fatigue, acute pain known as yak-back, and other problems including one known as yak-ass, circulation problems in the legs. In extreme cases it may even lead to a painful, chronic condition called sciatica, caused by the vertebrae in our spine compressing the sciatic nerve, which is the largest group of nerves in our body.
These problems are accentuated by the fact that the driver of a pedal propelled kayak cannot switch positions. This means that the above mentioned symptoms tend to occur shortly after the kayaker starts pedaling, and their severity can increase rapidly.
That is to say that if paddling a kayak in the L position is highly problematic from an ergonomic standpoint, pedaling a kayak in that position is notably worse.