In TP (tandem position) the width of base of support was narrowed down significantly, therefore test lasted only 10 s. During the test in TP one foot was placed directly in the front of the other (on the line) and the heel of the front foot was touched the toes of the rear foot. Tests were performed tests in TP with the left foot in front (TLF) and with right foot in front (TRF) separately. In THR group the placement of the operated limb in the front stance was called the TOF test, while the placement of the non operated limb in the front stance was called the TNF test. The results obtained in TOF position and TNF position were compared with tandem control index (TC - mean of results obtained from control group in TLF and TRF positions).