BACKGROUND: Heart rate is an accurate and easy to use method to
represent the energy expenditure during walking, based on physiological cost
index (PCI). However, in some conditions the heart rate during walking does
not reach to a steady state. Therefore, it is not possible to determine the
energy expenditure by use of the PCI index. The total heart beat index
(THBI) is a new method to solve the aforementioned problem.
OBJECTIVE: The aim of this research project was to find the
sensitivity of both the physiological cost index (PCI) and total heart beat index (THBI).
METHOD: Fifteen normal subjects and ten patients with flatfoot
disorder and twosubjects with spinal cord injury were recruited in this
research project. The PCI and THBI indexes were determined by use of heart
beats with respect to walking speed and total distance walked, respectively.
RESULTS: The sensitivity of PCI was more than that of THBI index in
the three groups of subjects.
CONCLUSION: Although the PCI and THBI indexes are easy to use and
reliable parameters to represent the energy expenditure during walking,
their sensitivity is not high to detect the influence of some orthotic
interventions, such as use of insoles or using shoes on energy expenditure
during walking.
