EFFECTS OF SITTING POSTURE ON VOLUME OF FOOT

The feeling of heaviness in the legs and distension of the feet which appears during prolonged sitting posture are due to an increase of volume of the lower limbs. Volume changes of the foot were recorded continuously on 32 subjects, during 78 experiments from 1 to 2 hours, with a constant water level plethysmograph. Results obtained were: (a) Sitting posture produces on the foot immersed in the water (32° o or 40°o) a volume increase of about 2·3 p. 100 after 1 hour and 2·8 p. 100 after 2 hours. (6)Increase of temperature from 32°0 to 40° c produces a volume increase of 2·1 p. 100 before 1 hour and 1·5 p. 100 after 1 hour of sitting posture. (c) Compression of the back side of the thigh produces a greater increase of the foot volume, (d) Three distinct factors, the effects of which are cumulative, are responsible for these increases: hydrostatic pressure, vaso-dilatation and disturb of venous blood return. These results support two ergonomics principles: (a) introduction of short and frequent pauses during sitting work;(6) the use of height adjustable seats. © 1969 Walter de Gruyter. All rights reserved.