Sunday, June 29, 2008

Shoulder Safety

Imagine a basketball balanced on a golf tee. The basketball is the end of your humerus bone. The indented part of the tee the basketball is balancing on is your shoulder joint. It’s not very deep, and it’s not very big, considering the large ball that’s resting on it. And therein lies the problem. The shoulder socket is very small, while the humerus bone resting on that socket isn’t. The shoulder socket is designed for range of motion, and not designed to be a weight bearing joint (like how paddlers use it for bracing, turning, or rolling). In contrast, the hip socket is a weight bearing joint – the bone is set deep in the socket for stability and to prevent a large range of motion. (This explains why dislocating a hip is horribly painful)

The ratio of a basketball to a golf tee is actually pretty accurate when describing the shoulder joint. Now imagine how easy it is to knock that basketball off the tee and you can see why shoulder dislocations are fairly common. If not for the skin, muscles, tendons, and ligaments that surround the shoulder, humans would perpetually walk around in slings. As it stands though, it’s only kayakers that perpetually walk around in slings. Usually, the paddle is the culprit when a kayaker dislocates his shoulder. Archimedes once said, “Give me a lever long enough and a fulcrum to place it on and I’ll move the world”. Your paddle is that lever, and although it’s only 197 centimeters long, it’s plenty long enough to apply the minimum pressure required to knock that basketball off the tee. Keeping your shoulder in a strong position while paddling is therefore of utmost importance. A strong position is one in which the elbows stay below the hands and the hands stay in front of the torso. The easiest way to achieve this strong position is by rotating your torso with all your strokes – especially strokes done at the back of the boat.

Below are two pictures of a sweep stroke. In the first, the paddler has rotated his upper body with the stroke. His elbows are bent and below his hands, while his hands are in front of his torso. This is a strong position. In the second picture a paddler has not rotated his torso when doing the sweep stroke. You can see that the elbow is above the hand, and the hand is not in front of the torso. This is a weak position.

Strong and weak shoulder positions can also be applied to rolling. In the first picture below the paddler is executing a sweep roll. Notice how he has twisted his torso as he rolls to ensure that his hands stay in front of his body as his rights himself. (One of the easiest ways to achieve this is by following the lead paddle blade with your eyes). His left hand and elbow stay tucked close to the body to maintain a strong position. In the second picture the paddler is not rotating with the sweep. This puts a lot of pressure on the shoulder and is a weak position. The shoulder has become a weight-bearing joint – something it was never intended to be.

This concept also works with bracing. It is often said that a low brace is safer than a high brace. In actuality, a poor low brace and a poor high brace can dislocate your shoulder equally well. Both braces should be executed with the bracing blade planted in the water in front of the paddler. Bracing perpendicular to the paddler, or behind the paddler (even worse) places the shoulder at risk. The farther back you brace the more you load the blade with weight, and the more you’re depending on the shoulder alone, and not the other muscle groups, like abs, obliques, and pecs to stay upright. A high brace is perfectly acceptable so long as the hands aren’t rising above the head.

A low brace is acceptable as long as the elbows aren’t rising above the hands or head. Below are four pictures. The first and third pictures demonstrate a shoulder-safe high and low brace, respectively. The second and fourth pictures demonstrate an unsafe high and low brace, respectively.


Chris Gallaway said...

Excellent! Clear and helpful coverage of an issue that's important to all paddlers. Thanks!

Chris Gallaway said...

Excellent! Very clear and helful coverage on a topic that's important to all paddlers. Thanks!

Anonymous said...

"Humerus", Herm, not "Humorous" which (Dare I say it?.....) might be the funny bone.

Herm said...

Doh, thanks. In our professional medical opinion there is nothing funny about that bone.

PeterD said...

Hmm, I seem to have learned differently on the low brace - having learned to bring the elbows up when doing a low brace. I checked a bunch of other sites and photos of low braces, and most seem to show elbows up. I'll have to go back to the books and instructors on this one.

Herm said...

Good point - many people do teach the low brace with the elbows up. We prefer to keep the elbows down because it feels more comfortable and the shoulders stay in a more natural position. From that position it is also much easier to do a reverse stroke to back yourself out of a hole, which is when a low brace is most often used. (A low brace with the elbows up is fairly one-dimensional - all you can do is push down on the water) Wrist position is also important in these braces. In a high brace the wrists are rolled back. In a low brace the wrists are rolled down. Play around with the low braces and see which method you like better. Thanks for reading!