Wednesday, August 19, 2009

Hamstring Theory, Yak Back, and Kayaking Ergonomics

This short article will attempt to examine the 'hamstring theory' about the source of back pain and leg pain in kayaking and kayak fishing, both as an explanation of the causes of these widespread ailments, and in practical terms related to what you can and should do to prevent them.

What are hamstrings?
Hamstring is the name given to any of the tendons at the rear hollow of the human knee.
A hamstring muscle is the name given to any of the three muscles constituting the back of the upper leg that serve to flex the knee joint, draw the leg inward, and extend the thigh.

What do hamstrings have to do with back pain and leg pain in kayaks?
Most people are short in their hamstring and calf, as a result of spending many hours every day seated in chairs, such as when doing office work, studying, dining, watching TV, commuting etc.
Therefore, when one sits in a kayak with legs straight, the hamstring tissue stretches, and that can be felt as pain.
This shortness of the posterior leg may cause stress in other parts of the body. It may compress nerves resulting in leg numbness or tingling. It can cause discomfort and pain in the lower back due to bad pelvis position, as the pelvis is attached to the hamstring muscles.
A short posterior leg prevents people form sitting fully upright in the L kayaking position: The hamstrings pull down on the back of the pelvis creating a 'slouch'. This rounds the low back and causes back pain.
Kayaking in the L position can also cause a sciatic nerve to get pinched . The sciatic nerve is a large nerve bundle that innervates the legs, and it is sensitive to compression:
Short hamstring muscles can cause the pelvis to shift enough to increase the pressure on the sciatic nerve. Pressure on the back of the thighs can also compress nerves, and cause circulation problems in the legs.
Kayaking in the L position may also lead to Hamstring Tendonitis: a condition which involves pain in the area above one or both knees, the biceps, and sometimes on the back of the upper legs. Tendonitis is the inflammation of the tendons that connect the muscles to the bone.

Conclusions, so far
The above diagnosis points to several problems caused by sitting in the L position, and involving hamstrings. Practically, it means that one way or another, most people who sit in kayak in the L position would feel some sort of physical discomfort, pain or injury - sooner or later.
That is simply because the L position is not fit for most people, or as most kayaking instructors and outfitters would put it - they are not fit for it.
This is where it's important to stress that the hamstring theory talks about the L position itself, as if the fact that people sitting kayaks did not have a backrest and footrests to hold them in place, and help them maintain their back in an erect position.
In other words, sitting in the L position in your living room would lead to similar sensations and problems if done for long hours, although your feet and lower back would have nothing to rest on.
Why is this important? Because the existence of footrests and a backrest aggravates to situation for you, as it causes a number of additional problems, some of which can be even more severe.

The hamstring theory - prognosis
In a nutshell, the basic idea is that since your body doesn't fit the L position, you can teach it to adapt to this position with exercise. When your body fits the L position, you'll be able to paddle correctly, that is using proper kayaking technique, and by that reduce discomfort and injuries.

Discussion
This prognosis may be true for some people who possess both time, energy, motivation and initial fitness to work on their power, flexibility and skills.
It's also a path that could lead some people to additional injuries, and more severe ones.
But most importantly, it's an approach that defies the purpose of recreational paddling and fishing by confounding means and ends: Instead of viewing kayaking and kayak fishing as possible outdoor fun activities, and mild, beneficial physical exercise, it relates to proper kayaking technique and posture as a goal in itself. Alas, this goal is practically not attainable for most people, who would keep suffering from a variety of undesirable symptoms related to the L position in itself, as well as in combination with the backrest-footrests system that all sit-in and SOT kayaks feature - simply because nearly all people in the modern world have short hamstrings, as short hamstrings are a typical result of the way we live.
This argument would have been moot, or just theoretical if alternative forms of kayaking and kayak fishing didn't exist, but luckily they do: The L kayaking position as well as the footrests and backrest that inevitably go with it are non-existent in the new, patented W kayaks that offer no-pain paddling and fishing.

3 comments:

cerebralyakker said...

Exercise is not such a bad idea, but since there's a better alternative now, why bother?

krisssss said...

Maybe the hamstring theory makes sense in another dimension?...
:)
kris

kaPAM said...

good piece
looks like the w yak works