The purpose of this study was to determine the effects of the some physical fitness’ parameters on the young women, during 12 weeks step-aerobic exercises’ program. The subjects performed step aerobic exercise three days per week and each session lasted for 60-90 min, the intensity of the heart rates was % 60-80. By doing statistical SPSS analysis packet of data in the program of the researchment the paired samples t-test was used in the comperation of the former and last test values differences of the subjects. Significant level was determined as 0,05 and 0,01. In this study the values of the body weight, body mass indexes, back strength, flexibility, right and left hand grip, vertical jump and aerobic power ((MaxVO₂) significant differences (p<0,01) were found statistically. The body fat percentage (%) also showed significant differences level of 0,05. But leg power and anaerobic power values (p>0,05) didn’t show significant differences statistically.Consequentl y, it was determined that at the end of 12 weeks’ aerobic exercises in some parameters physical fitness caused positive differences on the young women.

Key Words: Aerobic power, Exercise, Physical Fitness, Step-Aerobic