CONTENTS. 



PAGE. 



Introduction 1 



Researches by other investigators on energy requirements for walking 3 



Horizontal walking 3 



General considerations with regard to previous researches on horizontal 



walking 7 



Grade walking 8 



General considerations with regard to previous work on grade walking .... 15 



Plan of study 16 



Methods of measurement 18 



Universal respiration apparatus 20 



Tests of the universal respiration apparatus 25 



Treadmill 27 



Measurement of the step-lift 30 



Method of step-counting 33 



Apparatus for determining the pulse-rate 33 



Oscillograph 34 



Cambridge string galvanometer 34 



Electrodes 35 



Technique for securing records of the pulse-rate 36 



Determination of the body-temperature 36 



Determination of the blood-pressure 37 



Routine of experiments 38 



Subjects 41 



Statistics of experiments 42 



Discussion of results 90 



Basal metabolism 90 



Experiments with subject standing 94 



Metabolism during standing 94 



Carbon-dioxide elimination 94 



Oxygen consumption 95 



Respiratory quotient 95 



Heat-output 96 



General summary of measurements of metabolism during standing ... 97 



Comparison of metabolism for lying and standing positions 100 



Physiological effects of standing 101 



Respiration-rate with subject standing 101 



Pulmonary ventilation with subject standing 103 



Pulse-rate with subject standing 106 



Rectal body-temperature with subject standing 113 



Blood-pressure with subject standing 115 



Experiments with horizontal walking 116 



Metabolism of subjects while walking on a level 116 



Total metabolism during horizontal walking 116 



Increment in metabolism due to horizontal walking 120 



Total increment in heat-production 139 



Increment in heat per horizontal kilogrammeter 139 



Effect of speed upon metabolism in horizontal walking 143 



Effect of speed upon total heat-output 145 



Effect of speed upon total increase in heat-output 146 



Effect of speed upon increase in heat per horizontal kilogrammeter. . . 147 



Experiments with subject "marking time" 150 



Steps and step-lift during horizontal walking 152 



Number of steps in horizontal walking 154 



Step-lift during horizontal walking 155 



Possible causes for variation in step-lift 155 



Total step-lift per minute 156 



Step-lift per step 157 



Energy increment due to work of step-lift 157 



