2. 25 subjects. The test measurements will be conducted on an Elliptical trainer (Precor USA 576i EFX). The protocol includes 3 tests. In the first test, resistance and incline will be paired together in increasing order at the set device levels of 1, 5, 10, 15, and 20. In the second test, the resistance will be held constant at level 1, while the incline will be increased from levels 1 to 20 in increments of five. In the third test, the incline will remain constant at level 1, while the resistance will be increased from levels 1 to 20 in increments of five. Each subject will be tested over a 20 second time period for each of the changed resistances and inclines. The subjects will be instructed to keep a steady pace within the range of steps/min = 70-95.