Fig. 4. An example of normalized thorax and abdomen respiration waveforms during the isovolumetric maneuver by one participant.

a Normalized BIOPAC chest-belt waveforms and b Filtered NCS respiration waveforms. The intended paradoxical motion windows are marked by green-shaded areas and detected instances are shown by the positive value of dotted green lines. Timing of abdomen contraction, hold, and relaxation is denoted during the second cycle of the NCS waveform. Both BIOPAC and NCS can detect all three instances of paradoxical abdomen-thorax motion.