Energy expenditure during wheelchair propulsion in different levels of paraplegics

Background - Wheelchair is considered as an efficient means of locomotion with optimal independence for a non – ambulatory person with dysfunctioning lower limbs. A linear relationship between oxygen consumption (VO 2 ) and heart rate at submaximal levels has been repeatedly proven in able-bodied subjects, handicapped children, and paraplegics during arm cranking at different power levels. Therefore heart rate is used an indicator of energy expenditure. This study is aimed to evaluate the energy expenditure during standard wheelchair propulsion in different levels of paraplegics using Physiological Cost Index (PCI). Materials & Methodology - Male paraplegics (n=50,) age = 31.52 ± 5.20 (Mean ± Standard Deviation) years between T7 to T12 spinal level using wheelchair were included in the study. Patients were given 5 minutes time at the starting line in order to attain a steady resting heart rate which was measured by palpation of radial pulse.  Subjects were instructed to propel the wheelchair at their normal propulsion speed on a standard level corridor (walkway of 25 meters) for a minimum duration of 5 minutes to attain a steady physiological heart rate. At the end of 5 minutes, they were instructed to stop and steady propulsion heart rate was measured. Energy expenditure (PCI) was calculated by: PCI (beats/meter) = Steady propulsion heart rate – Resting heart rate (beats per minute / propulsion speed (meter/minute) Results - Descriptive statistics using mean and standard deviation and Pearson correlation was used. There was a strong correlation between PCI and duration since wheelchair used. Conclusion - There is strong correlation between PCI and duration since wheelchair used, but there is no correlation between PCI and different level of thoracic injury, American Spinal Injury Association (ASIA) score and speed of propulsion.