Fig. 5: Consecutive hammering tests.

a Some extreme sports, such as boxing and skiing, that potentially generate high impact force. b Optical image of the sensor subject to consecutive sudden strikes by a hammer (0.25 kg). c Capacitance retention histogram under continuous and stable strikes. d Capacitance change with the pressure of the SISP after the hammering strike test. e Capacitance response test of the SISP under continuous boxing strikes