Physiological cost index and surface electromyography of different walking speeds

Abstract

[Purpose] The purpose of this study was to clarify the relationship between aspects of the alteration of Physiological Cost Index (PCI) and surface electromyography and the walking speed. [Participants and Methods] The subjects were 35 healthy persons. They walked at five different walking speeds relative to their most comfortable walking, the free walking speed (FWS): -50%FWS, -25%FWS, FWS, 25%FWS and 50%FWS. Surface electromyography and the heart rate were measured, and the integrated value (IEMG), the median power frequency (MdPF), the mean power frequency (MPF) and the PCI were calculated. [Results] PCI at -50%FWS and 50%FWS was significantly increased compared with that of FWS. Although the IEMG increased with increase in walking speed, MdPF and MPF showed activity in the low and medium frequency bands. [Conclusion] The results of this study suggest that the PCI increased faster or slower than FWS, and IEMG increased with the increase in the walking speed.