The application of leg strength measurement system on human centrifuge

Abstract

Objective To evaluate the system for continuously measuring forces exerted on pedals on human centrifuge. Methods The measurement system consisted of force transmitting and signal processing units. The force transmitting unit included two pedals with air bladders and an inflating assembly. The signal processing unit was composed of Model 5502 pressure transducer, 5B series isolated signal regulation modules, DaqBoard/2005TM AID board and DASYLab 5. 6 data acquisition and analysis software. The system was evaluated on AMST-HC-4E human centrifuge by nine pilots. Results There was significant difference in the air bladder pressure (ACP) that reflected the force exerted on pedals between different +Gz levels and the ACP was also significantly correlated to + Gz (r=0.915, P< 0. 01), The relation between ACP and +Gz value could be concluded by a linear regression equation: ACP= 4.5 × Gz +4.2. The measured pressure patterns in bladder could be useful for judging how subject distribute his leg strength in performing anti-G maneuver (AGSM). Conclusions The system can measure subject's leg strength during his +Gz exposure. It could be useful in pilot' s + Gz tolerance evaluation and centrifuge training. Key words: Acceleration; Lower extremity; Exertion; Ergometry