Figure 1.

Strength–dexterity test demonstrating the slender spring, the hardware for force data capture, and a representative trial. A) The spring had a stiffness of 0.86 N/cm, length of 3.96cm, whereas the maximum force required for compression of the spring was c. 3 N. The spring was chosen such that it would become unstable when compressed at low force levels. B) The instrumented spring with miniature load cells mounted to the end caps. C) An example time series of the force data from the thumb (brown) and index finger (black) and the average representative force (blue) along with the sustained compression plateau in gmf (right).