A task analysis will help you understand what you want to do. It will dissect a complex set of actions and turn it into simple ones that can be evaluated easily.
Start the task analysis by breaking things down into their basic steps. If you feel inclined you can develop a Gross Task Analysis.
With the task broken down you can extract two key elements. You can see what human-machine interfaces are present. You can also see what actions are required for each step.
The human-machine interface will tell you what body parts will actually touch, or otherwise engage, the product/setup. The actions will determine what supporting body structure is needed. It will also show you which steps take the most effort and/or time.
Here is a quick example on vacuuming with a typical upright vacuum cleaner.
Task:
- Power up and vacuum an area of carpet.
Steps:
- Uncoil power cord
- Plug in power cord
- Turn vacuum cleaner on
- Place vacuum cleaner in ready position
- Push, retract, and pivot vacuum cleaner over carpet
- Turn vacuum cleaner off
- Unplug power cord
- Coil power cord
Human-Machine Interfaces:
- Power Cord
- Power Cord Plug
- Vacuum Cleaner Power Switch
- Vacuum Cleaner Handle
- Vacuum Cleaner Ready Position Release Lever
Actions:
- Uncoil/Coil Power Cord: Uses hands and arms to uncoil/coil cord and back for bending over to reach cord storage location. Cord needs to be unwound/wound around guide posts a dozen times.
- Plug/Unplug Power Cord: Uses hand to hold and push/pull plug into the power outlet and legs to walk to the power outlet.
- Turn Vacuum Cleaner On/Off: Uses finger to press switch.
- Place Vacuum in Ready Position: Uses foot to depress release lever and hand to hold the handle.
- Vacuum Carpet: Uses hand to hold handle, forward/backward motion of arm to move vacuum, side to side motion of arm and wrist to turn vacuum, legs to maneuver body behind vacuum.
Ergonomics is all about making things comfortable and efficient. So to make things comfortable you want to make the human-machine interfaces nice. Nice means it plays to the strengths and does not stress the body part interfacing with it.
To make things efficient you want to limit the actions as much as possible. Fewer actions equal less work which equals more time to play Parcheesi.
If you are going to buy a vacuum you want to find one that will make this task more comfortable and efficient for you to complete. Then it will be an ergonomic vacuum cleaner.
The power cord should be quickly accessible. You should not have to move other pieces to get to it. The area your hands and the cord needs to travel around the guide posts should be free or obstructions.
A mechanism that lets the cord fall off of the guide posts helps in efficiency. It adds two actions, pivoting the release mechanism down to release and up to hold the cord again, but it reduces the actions needed to uncoil the cord to almost nothing.
A retractable cord is also a plus.
The plug should be easy to hold in your hand with enough size and surface area to get a good grip and remove from the outlet with ease and plenty of room between you and the prongs.
The power switch should be easy to operate with good feedback to let you know you engaged it. It should click, light up, move and stay in a different position, or some other action that lets you know you turned it on or off.
The switch should also be accessible without having to move or reach around anything, or bend over.
The handle should be comfortable and sized so that you have a good grip. Padding will help with comfort and to dampen vibrations to your hand. Texture and shapes for your fingers to catch will all help you maintain control through the handle.
The handle should be at a height that allows you to maintain a good standing posture, no slouching, with your arm in a position of power. The middle of the range of motion for a joint is typically the strongest. In this case you want your upper arm to hang down with your elbow bent at 90 degrees. Since the vacuum cleaner does not require a lot of strength to operate a good bit of deviation from this position is allowable.
The handle should be positioned so that you can maintain a natural wrist position.
The ready position release lever should be easy to find and reach with your foot while you maintain a good standing posture.
Finally, the vacuum cleaner should be easy to push/pull and rotate.
There are many other tasks associated with a vacuum cleaner. Storing, changing bags and adjusting carpet height settings are all tasks you would want to consider when looking at a vacuum cleaner.
You can also use the task analysis to evaluate your cleaning pattern. You can even go so far as to change your room layout to minimize the amount of turning needed to vacuum the area, although your friends might look at you a little funny for doing so.
