As in Figure. 4e, three representative FBGs were selected, of which the Bragg wavelength shifts were read against the variation of distal edge displacement. Each data point was sampled by taking an average of three bending cycles. By fitting a curve along with those sampling points, the hysteresis could be measured as the disparity between the upward and downward bending, with the shadowed region representing the 95% confidence interval. Each hysteretic (or bending) cycle took around 2 s. These disparities could be varied, depending on the FBG locations. In general, they are very small (<0.051 nm), thus implying a low level of sensing hysteresis throughout such large bending cycles. To evaluate the longer-term sensing repeatability, the displacements of three selected lines at the peak of upward motion were calculated and shown in Figure. 4f. Altogether, the results suggest that the sensing was still promising with stable and reliable responses over 1,000 repeated bending cycles. Again, this repeatability could also be varied by the displacement locations. The larger bending displacement detected by our shape sensor, the higher its fluctuation found over such repeated cycles. The fluctuation among those three lines of displacement nodes can be readily comparable on a logarithmic scale. Note that the nodes on the distal side encountered the largest fluctuation (RMS fluctuation ~1.48 mm) as a result of its largest displacement detected.