A comparison of physiologic and physical discomfort responses between exercise modalities.

Turner, MJ, Williams, AB, Williford, AL, and Cordova, ML. A comparison of physiologic and physical discomfort responses between exercise modalities. J Strength Cond Res 24(3): 796-803, 2010-To determine differences in physiologic responses and perceived discomfort during maximal and submaximal exercise with 2 common exercise modalities, the elliptical cross-trainer (ECT) and the arc trainer (ARC) were used, which undergoes an excursion of motion using an arc pathway. Eighteen subjects (10 male and 8 female; age = 24.7 +/- 2.6 yr, height = 172.2 +/- 10.3 cm, mass = 69.8 +/- 14.9 kg, %fat = 22.5 +/- 8.1%; mean +/- SD) performed maximal exercise protocols on a treadmill (TML), the ECT, and ARC, Subjects also performed 3 10-minute submaximal exercise bouts on the ECT and ARC at 55%, 65%, and 75% of TML maximal oxygen uptake ((V) over dotO(2)max) in which heart rate (HR), (V) over dotO(2), ventilation, respiratory exchange ratio, and hip, knee, and low-back discomfort were monitored. All testing on the ECT and ARC were performed in a counterbalanced order. The (V) over dotO(2)max was greater during TML exercise compared with ECT (p = 0.007) but similar to the ARC. Both ECT and ARC elicited lower maximal HR values compared with maximal TML exercise (p = 0.0001). No difference was observed between ECT and ARC for V02 during the submaximal exercise bouts (p > 0.05). However, HR was greater during submaximal ECT exercise (p 0.0001). Perception of discomfort was not different between ECT and ARC for knees (p > 0,05) and lower back (p > 0.05) but different for the hips (p = 0.02). Similar (V) over dotO(2)max values were observed with ARC and TML modalities. Greater perceptions of discomfort were observed with ECT compared with ARC at similar submaximal exercise intensities, suggesting individuals with, or at risk for, lower-extremity joint pathology may benefit from exercise with modalities other than the ECT.