Force platform for stabilographic studies.

An analysis is made in the paper of a triangular force platform included in a computer system for postural analysis using Pravets 8M personal computer. The tensions generated in steel rings in the three corners of the platform, proportional to the moments of the forces with spontaneous fluctuations of the position of the centre of the force exercised by the experimental subject on the platform, are registered and amplified using three identical amplifying channels comprising tensotransducer, preamplifier and second-order low-frequency filter. The output signals of the three amplifying channels are fed to an analogue decoder generating an electrical signal proportional to the weight and to the anterior-posterior and lateral components of the force. The signals from the outputs of the decoder can be used for introducing visual feedback about postural stabilization. The regulations of the platform are maximally simplified so as to be used in clinical research.

[Work difficulty and the physical work capacity of female afforestation workers in forestry]. / Tezhest na truda i fizicheski raboten kapatsitet na zalesitelki v gorskoto stopanstvo.

The severity of labour in manual soil-preparation and planting has been studied and the physical capacity for work of the female workers--determined, who performed those basic afforestation activities in the national forestry. The severity of labour has been characterized by the values of oxygen consumption, energy-expenditure and pulse rate during work. The physical capacity for work has been determined by physical loading on the Lanoy bicycle ergometer , with submaximum degrees of loading. The maximum working capacity was calculated by the values of the pulse rate with submaximum degrees of loading according to Astrand method. The physical loading during manual soil-preparation is high (6.6 kcal/min, 27.6 kJ resp.), and that of planting--moderate. The maximum aerobic capacity of the afforestation female workers examined, was characterized by maximum oxygen consumption 2.04 dm3/min, 29.6 cm3/kg/min resp., and maximum pulse rate--177 beats/min. Energy losses during work surpassed, to a considerable degree, 30 per cent of the maximum aerobic capacity of the female afforestation workers. On the base of the results obtained, measures are proposed for the reduction of the severity of labour and for improvement of the organization of the work during the afforestation activities in national forestry.

Influence of the visual feedback for some parameters of the body oscillations on their stability.

In accordance with the hypothesis that in addition to the generalized information from the visual feedback about the body oscillations, the information from the different parameters of the oscillations may also play a stabilizing role for the vertical posture of the body and its balance, studies were carried out on the influence of the parameters of body position, velocity of the body oscillations and accelerations on body stability. The results have shown that the visual feedback about the position of the body and about the velocity of the oscillations leads to stabilization of its balance. Visual feedback about the accelerations of the body oscillations also has a stabilizing action on the vertical posture and equilibrium. Its influence did not prove greater than the visual feedback about the velocity of body oscillations. Repeated recordings of the body oscillations under the experimental conditions manifested a slight initial training effect, expressed in a decrease of the total way of the body oscillations.