The Relationship Between Lean Body Mass, Resting Metabolic Rate, and Peak Oxygen Consumption in Spinal Cord-Injured and Able-Bodied Individuals

Abstract

The purpose of this study was to examine the differences, between able-bodied (AB), paraplegic and quadriplegic individuals, in lean body mass (LBM), bone mineral content (BMC), mineral free lean tissue mass (MFL), resting metabolic rate (RMR), and peak oxygen consumption (peak VO2) and to examine the appropriateness of AB equations for the prediction of RMR in paraplegic and quadriplegic individuals. The study involved a total of 50 participants (10 male individuals with paraplegia, 9 female individuals with paraplegia, 6 male individuals with quadriplegia, 16 male able bodied and 9 female able bodied). RMR was assessed using open circuit spirometry. The amounts of LBM, MFL, and BMC were assessed using dual energy x-ray absorptiometry (DXA). Peak oxygen consumption was assessed using arm crank ergometry (ACE) with open circuit spirometry. All statistical analyses were conducted at the .05 level of significance. The results showed that AB individuals had significantly higher values than individuals with quadriplegia for peak VO2, maximum heart rate, and RMR. AB individuals also had significantly higher values than paraplegic and quadriplegic individuals for BMC, MFL, and LBM relative to height. Male individuals with paraplegia had significantly higher values than individuals with quadriplegia for peak VO2, maximum heart rate, RMR, and BMC, MFL, and LBM relative to height. Results also indicated that regression equations used to predict RMR from LBM in the AB population significantly overestimated RMR for individuals with quadriplegia. It was concluded that: (1) Male AB and paraplegic individuals demonstrate significantly higher peak oxygen consumption and maximal heart rate values during maximal exercise testing. (2) Individuals with quadriplegia have significantly lower amounts of BMC, MFL, and LBM relative to height than AB and paraplegic individuals; and (3) Regression equations predicting RMR from LBM, based on AB data, may be inappropriate for use with individuals with quadriplegia.