Reliability of physiological cost index measurements.

The reliability of physiological cost index (PCI) measurements under steady state, non-steady state and post-exercise conditions was evaluated. Thirty volunteers (15 male and 15 female) aged 20-30 years participated in the study. None of the volunteers had a history of smoking, respiratory disorder or locomotor abnormalities. Each subject walked at his/her preferred walking speed on an electronic treadmill (Weider TM 2000) and pulse rates (radial pulse) were monitored by the palpatory method. The test was performed twice with an interval of one week between tests. The gender effect on PCI values was evaluated using the independent t-test while the test-retest reliability was determined by the Pearson product-moment correlation method. Results showed no consistent gender difference in PCI. It also revealed a high test-retest reliability (r = 0.843-0.944) for the non-steady state PCI (NSSPCI), the steady state PCI (SSPCI) and post exercises PCI (PEPCI). Analysis of variance showed that the correlation coefficient were significantly different from zero (p < 0.001). It is concluded that PCI is an easy to-use, valid and reliable measure of energy expenditure and it is recommended as a useful tool for physiotherapist in the assessment and evaluation of functional performance.