Background: Currently, due to the high prevalence of overweight, obesity and modernization of life, walking on a treadmill is welcomed instead of walking on the ground. The aim of the study was to compare the effects of treadmill and ground walking, on maximal oxygen uptake (VO_2max), body mass index (BMI) and body fat percentage among inactive overweight women.

Materials and Methods: In this semi-experimental study, 30 healthy, inactive, and overweight women volunteered to take part in this study. After performing a pre-test, the participants were randomly allocated into three equal groups (n=10): walking on a treadmill, walking on the ground, and control. The walking training program was performed three sessions per week for eight weeks with 60% to 85% of heart rate reserve. Before and after eight weeks, the VO_2max was assessed by the Queen’s step test, BMI by dividing weight (kg) by the square of height and the body fat percentage was determined by measuring subcutaneous fat in three points with Skinfold calipers.

Results: The results showed a significant decrease in BMI in the two groups of walking on the treadmill and ground. Moreover, there was a significant difference in VO_2max among the three groups. However, there was no significant difference in BMI and body fat percentage among the three groups.

Conclusion: Since walking on the ground can improve VO_2max, it can be more helpful to prevent obesity than walking on a treadmill.