Introduction to Body-Powered Hooks
by Amber Henson, on Feb 8, 2022
Hooks are one of the most common terminal devices for body-powered prostheses. They can handle a wide range of tasks, from gripping a steering wheel to carrying a heavy bag of sand or concrete mix. There’s a reason the shape of most hooks hasn’t changed in almost a century — it just works! The tines or “fingers” of the hook are slender and curved to make it easy for the user to see the tips. The tips close in a precise pinch that is consistent and repeatable. The opening and closing of the hook is operated by the upper body movement of the user. You can watch it all come together in the gif below:
There are many benefits to a body-powered prosthesis. For new prosthetic users, body-powered hooks are easy to open and close and give them two strong "hands" for lifting and carrying. If you work or have hobbies that are outside or in a dusty or rough environment, you’ll appreciate having this heavy-duty terminal device. Additionally, body-powered hooks are lightweight — they don’t need the battery pack required for myoelectric devices.
Because the person uses their shoulder and back to open and close the hook, they receive immediate feedback about how the prosthesis is being used. With myoelectric devices, the person’s muscle contractions generate electrical signals that activate the prosthesis. But with a body-powered hook, the person is moving their body in a straightforward manner, so they have more feedback available when grasping objects.
Most myoelectric terminal devices can’t get wet — but that’s not a problem for a body-powered hook. Dust, moisture, humidity, heat, mud, oil, paint, wood finish — you name it, the hook can handle it. There are also no worries about the batteries running out in the middle of a project, as sometimes happens with a myoelectric device. The hook can work as long as you can and you never have to worry about recharging it.
Besides the hooks you can see in the photo and gif above, another option is the V2P. What sets it apart is the variable pinch force that you can use with it, allowing the user to dial in the grasping strength of the device. It also has rubber pads and is a bit wider than other hooks, meaning that when you pick up objects, you can be sure the device won't scratch them and those objects can be larger.
Some points to keep in mind when considering the body-powered hook: body-powered devices can be rough on the back, shoulder and residual limb, and the more pinch force that’s required for the task, the more the user has to exert themselves. Moving one’s shoulder and upper limb to control precise terminal device limits can result in overuse and repetitive stress injuries. To combat these, our clinical therapy specialists teach patients how to use their device in ways that minimize the risk of injury. Another path to avoiding injury is to have more than one type of device — such as a myoelectric in addition to a body-powered.
Would you like to learn more about body-powered hooks and what they can do to make your life easier? Please contact us and let us know you’re interested in a complimentary consultation. We will discuss all available options for your limb difference level. If you’re already using a body-powered hook, please comment below with your thoughts on this device. Thanks for reading.
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