Step exercise remains a popular form of low-impact aerobic exercise. Because the height of the platform can be adjusted, all ages and populations can participate in this form of dance exercise. Although injury rates are low for shorter heights, the energy cost decreases linearly with height. This research study investigated the effect of step distance (DT) on energy cost (VO2) and knee joint angle (KJA) during step exercise. The purposes were: 1. To determine if doubling the footfall distance from the platform would increase the energy cost independent of step height (HT), and, 2. To determine how step DT affects KJA. Previous research has shown that increasing step HT increases both VO2 and KJA. While a higher VO2 is beneficial, the increase in KJA is not, because it increases the risk of patello- and tibio-femoral joint pain and injury. Trained female volunteers performed step exercise at a cadence, or stepping rate, of 30 cycles/min on platforms of two HTs (10.2cm[low] and 20.4cm[high])and two footfall DTs (30.5cm[short] and 61cm[long]). Test order was randomized for either the short or long DT used for both HTs. Three step patterns (basic, turn, cross-over) were used in all combinations of HTs and DTs. Each combination was measured for heart rate and respiratory gases for four minutes, giving a total of 48 minutes of step exercise, measured on two test days. Stationary KJA was measured for all DTs and HTs. Results of repeated measures MANOVA showed mean values for KJA significantly (p<.05)decreased for both HTs as the DT increased from short to long (-17.2% and -19.6% for low vs. high HT). Mean values for VO2 for the last two minutes of each combination indicate increases in either DT or HT significantly (p<.05) increased VO2 across all step patterns. Heart rate and respiratory exchange ratio showed similar increases when either DT or HT was increased. The cross-over pattern provided a significantly (p<.05) higher VO2 than either basic or turn pattern for all test conditions. These results suggest that people who are unwilling or unable to use a step height greater than 10.2cm can increase the intensity of exercise by simply stepping further away from their step.Keyword(s): adult physical activity/fitness, exercise/fitness/physical activity, safety/injury prevention