Training measures to improve neuromuscular coordination are becoming ever more popular for both prevention and rehabilitation, not only in athletes but also patients receiving joint replacements. Numerous proprioceptive training measures and devices are used to train the sense of balance. Parameters suitable for quantifying the results of therapy are largely lacking. Herein, a simple method for quantifying the balancing on one leg using the therapeutic device (Posturomed) commonly employed to train balance in the upright stance. The horizontal movements of the oscillating suspended platform were recorded in two orthogonal directions using a non-contact measurement system. To simulate disturbance of the upright stance, a mechanical deflection device was applied to the platform. The physical characterization of the measuring system was done using rigid masses. 13 volunteers adopting a one-legged stance were investigated. The measured displacement in the medio-lateral (ML) and AP directions were used to establish a balance index. Examination of the oscillatory behaviour of the platform revealed the path signal to be a suitable parameter for analyzing the platform movements. Differences in balance characteristics between AP and ML movements could be quantified. Frontal disturbance of the upright stance is equilibrated more effectively than lateral disturbances. Combined with a non-contact path measuring system the therapeutic device is suitable for characterizing balancing ability in an upright one-legged stance. To obtain more detailed information on the neuromuscular mechanisms involved, further studies are needed.