Saturday, November 19, 2011

Kitchen Ergonomics - Part One

I have been thinking for some time of doing a series of posts regarding kitchen ergonomics. This subject is near and dear to my heart, as I personally have had a number of injuries that have left me with limited abilities and use of my hands and arms.

For those of you who are involved with preparing food, I'm sure you can see how much you actually use your hands when doing these tasks.

Given that in my "real life", I earn a living teaching and practicing health and safety (including ergonomic principles), I thought it would be quite fitting to show readers how to incorporate ergonomics principles at home and in the kitchen.

As there have been an array of "ergonomic products" out on the market, I also thought it would be a good idea to dispel any untruths or statements being made about ergonomically designed equipment.

Nowadays, "ergonomics" is a term that is thrown around very frequently. It is commonly used incorrectly to describe tools that are designed with a variety of appealing curves and grooves.

Ergonomics is based on a science called human factors. Human factors is the study of understanding the human body. True ergonomics, therefore, is reached when a design complements the human body. That being said, a tool should be made to fit the user and not the other way around.

Neutral Postures:
As humans, our bodies have limits. There are safe ways to work and there are unsafe ways work.

Safe ways to work include maintaining postures that are "neutral". Neutral postures of the hand allow for parts of the body to be in positions while exerting minimal strain.

As you can see in the pictures below, the most neutral posture of the hand is when it is in line with the wrist and forearm.

Awkward Postures:
Awkward postures leave the body in positions where those parts being used have increased strain. Leaving the body in these positions for:

(a) prolonged periods of time (static postures); or
(b) adding force when doing work; or
(c) doing repetitive movements over time; or
(d) any combination of the above

can render those parts of the body at an increased risk for injury.

As you can see in the pictures below, any posture that puts the hand out of line with the wrist and forearm is an awkward posture.

The Pinch Grip:
A pinch grip is created when the thumb and finger(s) are used to pinch and grip an object. We put our hands in this type of posture a lot in our daily lives. Think of pinching and griping when using a key.

This type of grip uses the small muscles of the hand arm, which actually fatigue quite easily. When a muscles fatigues, it tends to rely on other muscles and body parts to compensate. When this occurs, those parts of the body are more prone to injury.

The Power Grip:
Using a power grip is an all-around better way to grip. A power grip uses the whole hand in a fist-like manner. The body moves away from the pinch movements and optimizes good body mechanics.

(Just remember that even though power grips are better postures for work, they have their limits too.)

Like in any hand postures, power grips can also be awkward. As stated before, any posture that leaves the hand out of line with the wrist and forearm is awkward.

Enter the knife. As one of the world's oldest tools, the knife has been made into many different shapes and designs. However, most fall short for kitchen ergonomics.

When gripping a knife, you can see that a pinch grip is used. Also, using a knife can put your hand in many awkward postures.
Pinch grip + awkward posture = poor ergonomics.
This tool does not fit the user.

The Right-Angled Knife:
My favourite kitchen knife to use is one with a right-angled blade.

As you can see, the design of this knife allows the user to use a power grip while maintaining neutral hand postures.

Power grip + neutral posture =  good ergonomics.
This tool fits the user.

Blades of this sort can be found, sadly, mainly in stores catering towards people with disabilities. They are also quite readily available over the Internet. The price is reasonable and is well worth the investment!

In my opinion, the use of proper tools could prevent injuries and disabilities from occurring.

The Mezza Luna:
A mezza luna or "half-moon" is a type of knife that is more readily available in kitchens stores. This knife works ergonomically in two ways.

As you can see, the design of this knife also allows the user to use a power grab while maintaining neutral hand postures. In addition, given its two handles, the knife reduces the amount of force each hand has to exert. Reducing the amount of force, or work that is applied by the body, renders the body at a lower risk for injury.

In practical terms, when you have something that is difficult to cut, because of its size and or density (e.g. squash, watermelons, cabbage, potatoes/yams, etc.) this blade cuts through them like butter.

In summary, when looking at kitchen ergonomics, look out for the following three hazards:
1) Posture - use proper body mechanics to remain in neutral postures
2) Force - reduce the amount of force put on to the body
3) Repetition - limit the amount of repetitive movements you make

Safe cooking!

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