Passive Muscle Force and Pressure Monitoring

Data was collected using a custom LabVIEW program (NI USB-6009 DAQ) to simultaneously record input from the force transducer and IMP sensors. The gauge pressure in each passive trial was adjusted so baseline was at zero for the length of L_o and normalized by the maximum pressure for each sensor, referred to as relative pressure as a percentage of maximum. Similarly, force was adjusted at L_o and normalized by the maximum force. Similarly, force was shifted to zero at L_o and normalized by the maximum force. The peak force was identified and corresponding pressures from the two sensors were found at each muscle length. Active force/IMP data was not the focus of data processing, as the study goal was to mimic tendon transfer surgeries in humans, where only passive force is evaluated and no muscle activation occurs. The effects of muscle activation have been reported previously by Davis et al (2003) (link) and Winters et al (2009) (link).