<qa>  What is the most common treatment at this stage?Patients suffering from End Stage Renal Disease are commonly involved in haemodialysis treatment, which is the most common treatment at this stage. Haemodialysis substitutes the renal function but is associated with several alterations that lead to decrease in functional capacity and health related quality of life HRQoL. Many studies show that functional capacity, physical activity level and HRQoL is significantly worse than their healthy sedentary age - matched counterparts. It is unknown if low physical activity, uraemia or anaemia are responsible for the decreased functional capacity of this cohort. Physical performance tests are frequently used to assess haemodialysis patients since is a feasible and low-cost evaluation. The purpose of the present study is quantified how the functional capacity changes over a -6 months period in a group of haemodialysis patients. Additionally the investigators pretend to calculate values absolute and relative reliability that have not been yet reported Short Physical Performance Battery, one-leg balance and Timed Up and go. 