Objective: The effect of an orthosis supply in patients with paresis caused by poliomyelitis was to be proved. The main questions was if an orthosis supply might improve the bodily functionality in daily life and especially the muscle activity of the lower limbs and trunk. Design: nonrandomized before-after trial with 3 months follow up. Setting: institutional practice, ambulatory care. Participants: In a consecutive sample of 13 patients (average age: 63.8 years, 9 female, 4 male) with partial paralysis of the quadriceps muscle and weakness of the dorsal flexors of the foot and instability of the knee joint caused by poliomyelitis anterior acuta 40 years before a femoral orthosis supply was indicated. 10 of them fulfilled the inclusion criteria for the study (average age: 64.5 years, 7 female, 3 male). Interventions: The activity of 8 specified leg and trunk muscles (m.) had to be described 3 months before (baseline=t0), immediately at orthosis supply (t1) and after further 3 months of gait training with the orthosis (t2). Main Outcome Measures: The muscle activity was described by the surface- electromyography (s-EMG). By means of the kinematic gait analysis via 3-dimensional ultrasound analysis of movement the knee joint angle and the stance duration of every single leg was detected at the same times. The quality of life was measured by means of 36 Items Short Form Health Survey (SF 36). The significance of all evaluated parameters was detected by the Friedman test (level of significance p