[Energy requirements for walking]

The energy requirement of walking, expressed indirectly by the oxygen consumption per kg body weight was assessed during different speeds of walking on a treadmill within the range of 3-12 km.h-1 in 87 untrained healthy men aged 17.5 to 60 years. The dependence of VO2.kg-1 on the speed of walking is non-linear in the mentioned range. Most suitable is the two-component linear model which in the range of 3-7 km.h-1 has the shape of VO2.kg-1 (ml.kg-1.min-1 = 3.207.v/km.h-1 - 1.777, r = 0.932 with a mean predicting error of 1.5.ml.kg-1.min-1, in the range of load of 7-12 km.h-1 VO2 = 7.120.v - 29.168, r = 0.941 with a error predicting of 3.73. The polynomic model of relations in the entire range of 3-12 km.h-1 is VO2 = 4.503 - 0.108.v + 0.379.v2, r = 0.922 with a predicting error of 4.43 ml.kg-1.min-1, and finally the exponential model has the shape VO2 = 4.360 exp (0.223.v), r = 0.861 with a mean predicting error of 6.84 ml.kg-1.min-1 in the entire range of load intensities. The justification to express the relationship between the oxygen consumption and the rate of walking by a two-component linear model as well as by non-linear models is confirmed also by the high correlation coefficient (p < 0.001 in all instances). The error of assessment of VO2.kg-1 from the speed of walking is 10% or less in all models. The mentioned models, in particular the linear one, can be used for evaluation of physical activities involving walking outdoors.