Various exercise modes are used to increase physical fitness levels and provide health benefits. These modes also are characterized many ways, e.g., weight bearing vs. non-weight bearing exercise and leg vs. arm-leg exercise. The purpose of this study was to evaluate peak cardiovascular and metabolic responses produced on the Reebok Body Trec elliptical arm/leg device (RBT) and compare physiological responses to peak values produced on the treadmill (TM), the Cybex cycle (CC), and Schwinn Airdyne (AD). Twenty male (N=8) and female (N=12) subjects completed one peak test on each of the four machines. Peak oxygen consumption (VO2peak), peak heart rate (HRpeak), peak expiratory ventilation (VEpeak ), and peak respiratory exchange ratio (RERpeak ) were measured at the end of the RBT, the CC, and the SA tests using the Polar Heart Rate monitor and Aerosport TEEM 100. The TM peak responses were obtained using the Marquette Case electrocardiographic monitoring system and the Sensormedics 2900 metabolic system. Peak criteria used for all exercise modes were volitional fatigue or the subject's termination of the test. Differences in physiological data were assessed using a one-way repeated measures ANOVA with V02peak, HRpeak , RERpeak, and VEpeak serving as the dependent variables.VARIABLESTMCCRBTSAV02mMg/min35.4 ± 1027.8 ± 1 la30.1 ±9a29.4 ± 10 aHRbpm177 ± 18161 ± 19169 ± 17b168 ± 18 bRER1.14 ±.111.03 ±.l 1c.97 ±.09 °1.10 ±.15VE93.7 ± 2572.3 ± 22'75.5 ± 20 d80.0 ± 23Peak values with the same subscript are not significantly different, (p<O1).The TM a produced significantly higher V02peak than compared to the other modes. The RBT, SA, and CC were not significantly different. The TM produced a significantly higher HRp( than did the RBT, SA, and CC. Although the RBT and SA HRpeak were not significantly different, these modes were significantly higher than the CC. As to the metabolic data, the RBT and CC RERpeak values were significantly lower than the TM and SA values. The TM VEpeak was significantly higher than the RBT, CC and SA values. The RBT and CC VEpeak were not significantly different. In terms of V02peak, HRpeak, and RERpeak, the data found the RBT to be comparable to the non-weight bearing, arm-leg SA, while the SA VEpeak was higher than the RBT. The data are in agreement with existing studies showing that TM exercise produces a higher V02p( even when compared with combined arm-leg exercise modes. Although the obvious differences among the RBT, SA, TM, and CC exercise modes are weight bearing vs. non-weight bearing, and leg vs. arm-leg exercise, the data suggested that other factors such as restriction of blood flow and amount of muscle mass recruited may influence peak cardiovascular and metabolic responses.