The aim of the study is to determine the effect of functional exercise and training counseling by kinesiotherapist in addition to the basic exercise program of cycling during dialysis on physical performance of dialysis patients.

Study will include 86 dialysis patients. Investigators will first test the strength of lower limbs with sit-to-stand test, handgrip strength, flexibility, balance, submaximal aerobic capacity, physical characteristics and clinical parameters. After that randomization of patients in two groups will be made - one experimental and one active control group. Patients who will refuse to exercise will be invited to a non-randomized inactive control group (without exercise).

The experimental group will attend 3 times weekly a guided functional exercise before the dialysis procedure for 20 minutes and perform a cycling session during dialysis in the first phase of the study, which will last for 8 weeks. During this time experimental group will receive exercise counselling; instructions how to practice at home will be given by examples and training during functional exercise predialysis sessions.

In the second phase of the study for additional eight weeks participants will be instructed to exercise at home using the skills mastered during the first study phase on non-dialysis days, and continue with the program of intradialysis cycling. Investigators will give them advice, monitor and motivate them.

The active control group will perform intradialytic exercise (intradialysis cycling equal to cycling program of experimental group) during dialysis procedure for four months.

The primary end-point of the study is a change in the 10-repetition sit-to-stand test time as a measure of strength of lower extremities.

Exercise program will be run by a kinesiologist. Main hypothesis is that the guided functional exercise under the surveillance of a kinesiologist added to intradialysis cycling program statistically significantly improves patient's physical performance as compared to the program of intradialysis cycling alone.

Inclusion Criteria:

• dialysis patients on renal replacement therapy with chronic hemodialysis,
• duration of hemodialysis treatment for at least 3 months,
• age 18-90 years,
• capable of independent walking and independent feeding.

Exclusion Criteria:

• the presence of chronic malignant or infectious disease,
• uncontrolled arterial hypertension with an average of the last five pre-dialysis blood pressure values above 180/100 mm Hg,
• unstable angina pectoris or Canadian Cardiovascular Society class 2-4,
• heart failure New York Heart Association class 3 and 4,
• the presence of a psychotic illness or a mental disability,
• a condition with an amputated limb (more than 2 fingers on the lower limb and / or more than 2 fingers on the upper limb)
• any other condition that causes the clinical unstability of the patient (i.e. repetitive gastrointestinal hemmorrhagies, liver cirrhosis with frequent exacerbations, advanced dementia with poor cooperation of the patient)