STEP-LIFT IN GRADE WALKING. 



245 



Step-lift per minute. In considering the step-lift per minute, recorded 

 in column g of tables 52 to 55, it is seen that although the variations 

 present in horizontal walking between experimental periods with like 

 conditions are likewise to be found here, the amount of lift per minute 

 increased in approximate conformity with the speed for the same grade. 

 It may also be noted that the lift per minute for the same or approxi- 

 mately the same speed increased with the grade, and that the total lift 

 reached a very appreciable amount at the higher grades and speeds. 

 Thus, E. D. B. had a total step-lift per minute of 7.1 meters when 

 walking on a 30 per cent grade at 69.5 meters per minute and on a 40 

 per cent grade at 65 meters per minute, as compared with a total step- 

 lift per minute of 1.7 meters on a 5 per cent grade at 65.4 meters per 

 minute. (See table 55, p. 209.) 



Step-lift per step. The lift per step likewise shows an increase with 

 the higher grades and speeds. W. K., on March 4, walking on a 3.6 per 

 cent grade at 69 meters and 114 steps per minute, had a lift per step of 



TABLE 66. Average step-lift per step of E. D. B. in grade walking for approximately 

 the same speeds but with varying grades. (Values per minute.) 



1.2 cm., while on June 17, on a 25 per cent grade at 67 meters and 120 

 steps per minute, it was 4.6 cm. (See tables 15 and 54, pp. 71 and 199.) 

 A summary of the data obtained for the lift per step -of E. D. B. during 

 grade walking is given in table 66, grouped according to grade and 

 speed. The values for horizontal walking (0 per cent grade) are 

 also given for comparison. The lift per step for E. D. B. with a 5 per 

 cent grade and a speed below 60 meters per minute was 1.36 cm., only 

 slightly greater than the average found during horizontal walking 

 (1.18 cm.) for approximately the same speed. For the highest grades 

 and speeds, however, the lift per step was between 6 and 7 cm. 



