Comparison Of Oxygen Consumption On Different Brands Of Elliptical Trainers In The Development Of A Metabolic Prediction Equation

Purpose: The primary purpose of this study was to determine the effect of elliptical trainer brand on gas exchange data as well as to develop separate equations that are specific to certain brands. Methods: Twenty-three healthy volunteers participated in the study (22.3 ± 4.6 yrs, 172 ± 8.2 cm, 67.5± 9.3 kg). Subjects completed a treadmill VO2max test to determine fitness level, followed by two testing sessions on two different brands of elliptical trainers, the Precor EFX 576i® and the TRUE TS1®. Subjects exercised at the same watt level on each elliptical trainer as determined by resistance and cadence. Elliptical trainers and testing sessions were randomly assigned so that each subject was measured on each machine for six 5-minute stages for a total exercise time of 30 minutes per session. Oxygen consumption (VO2), heart rate, rating of perceived exertion (RPE), and caloric cost of the exercise were measured during each session. A 2 (machine) x 3 (workload) repeated measures ANOVA was used to analyze differences between machines. Stepwise multiple nonlinear regression analysis was used to develop metabolic equations for submaximal elliptical trainer exercise on both the Precor and TRUE. Results: Significant differences were found between elliptical trainer brands for all variables analyzed (p<0.001), with the TRUE eliciting higher values than the Precor for equivalent watt output readings. Oxygen consumption values at the same watt output reading were 6.85 ± 4.4 ml/kg/min higher on the TRUE for watt levels between 107 and 131 watts. Two separate metabolic equations were developed for submaximal elliptical trainer exercise on the TRUE (R2 = 0.95, SEE = 2.6), and the Precor (R2 = 0.92, SEE = 2.4). Conclusion: Differences exist in physiological responses to submaximal elliptical trainer exercise at the same machine-given watt levels. These differences may require the acceptance of a metabolic prediction equation that is specific to a particular brand of elliptical trainer.