Like modern avionic instruments which are more sophisticated and sensitive (and capable) than in the past, modern coaxes with softer, lower-loss dielectrics are more easily damaged.
Bending, stretching, and kinks can force the center conductor to one side. This disturbs the common axis of the conductor and shield — they are no longer concentric — and shows up as a change in impedance at the point of "injury." This can actually be seen on a Time Domain Reflectometer (TDR), an instrument which examines cables for signal reflection, appearing as an electrical "bump" (or dip).