Trigger-shifters alternative for shifting with limited hand strength

Twist (grip) shifters are an inexpensive and reliable technology common on recumbent trikes. They have two main drawbacks:

1. They are ergonomically mal-positioned for most vertical handlebar situations as they are intended to be gripped with the thumb and fore-finger, but, instead, are positioned at the heel of the hand.
2. The twisting action to shift gears can affect the steering.

Due to the first drawback, people with limited hand-strength can have difficulty operating grip-shifts mounted in a vertical position.

We have been experimenting with alternatives to conventional grip-shifts on recumbent trikes and have mounted trigger / paddle shifters in several different positions with the intent of serving the needs of people with macro-movements, but limited hand-strength. Causes of limited hand-strength include stroke and other forms of full or partial paralysis, neurological conditions, and age.

The shifters shown worked well for some clients and potential clients with low hand-strength. The position seemed to be the best of all the positions we tried when used with macro push movements.

It would be relatively easy to re-arrange them to work in pull-only situations.

These shifters are quite reliable and almost as inexpensive as grip-shifters so the investment cost of this conversion is low.

People with stroke, Parkinsons, Ataxia, ALS, MS, and cerebral palsy could have improved shifting by using these shifters as shown.