People that conduct industrial or academic research are usually lost and wonder what we use prosthetic arms for. They regard the Holding Of A Bottle (TM) or the Holding Of A Paper (TM) as absolute key activities that they then summarize as "It is the little things that make the difference" to sell their prosthetic arms or the new ideas they try to push. However, elevating Activities of No Particular Prosthetic Need to the end all be all in prosthetic arm benchmarking does seem to mark the beginning of the end, the failure before having even started. On the other hand (pun!), I really use my prosthetic arms to conduct physical work.
That, as it appears, was not at all to be expected, were one to consider actual developments in the field and were one to think these were serious.
As an example, the photo shows a part of a bed sofa (left in the image) that weighs around 25 kg that I bi-manually moved up to the attic (ladder, hole in ceiling, above there is the attic, so vertically up and through that hole goes the bed frame). This is just one part of furniture that got moved around here recently. That bed alone consists of five parts and there was a lot more stuff that got moved around that night.
It is not just pushing 25 kg for a short moment. It is moving it up the ladder to the attic and storing it there, all the way, full circle. Along with the rest of the stuff. I worked on such tasks for about eight hours last night. Now that is what I call exposure to physical activity and realistic loads for prosthetic arms to support. Accidentally I tore up a small connector steel cable, but only through inattentive lateral damage. I have replacement parts so within a few minutes I was back at work again.
Please, if you do research, keep in mind that there exist real world applications for real prosthetic arms that need to urgently function under loads such as this. I regularly need to lift and shift weights around 20-60 kilograms. This is definitely not an exception. I cannot publicly post images of my real everyday work though. But imagine two of these bed frames at once, or three. Then you get the picture.
There is no way any pansy boy prosthetic can ever do that, and if you keep building and selling pansy boy stuff and tell everyone that you consider your stuff "relevant", or "modern", or maybe even "useful", I will have my eyes on you.
Because the continuation of my active life style depends on you researching and building useful prosthetic devices and arms.
So it is a simple act of self preservation when I will voice my concerns and when I will test new devices very critically.
To avoid surprises for you all, I will now tag examples of bi-manual tasks on this website. So with one click, you will be able to view these real world examples that make prosthetic arms shine through being really useful.
So, if you work in that field of academic or industrial prosthetic hand or arm research, best to drop whatever it is you are doing because I bet it was not such things as shown here.
Now, go and build actually useful hands and arms. Implement test procedures to test the use and capability of real products in a realistic way. Just because you cannot perform hard tasks does not mean an amputee cannot, as much as that (alone) might (and even should?) disturb you.
When moving stuff through my place, cleaning it out, I hauled ass for eight hours, with the weights and sizes as shown above. Not a bit of muscle ache after. No seriously damaged parts. But big question marks for massively overpriced "bionic" arms ("toy" arms).