138 
MUSCULAR WORK 
the curve for the total heat output per minute with varying revolutions 
shows 7.61 calories at 70 revolutions per minute, and 15.04 calories at 
130 revolutions per minute. The 
lower curve, which represents 
the total amount of effective 
work per minute, ranges from 
1.565 calories at 70 revolutions 
to 2.425 calories at 130 revolu- 
tions; the form of this curve 
is therefore what would be ex- 
pected from the calibration curve 
for this ergometer for a mag- 
netization of 1.5 amperes, inas- 
much as after 70 revolutions per 
minute the heat per revolution 
decreased as the speed in- 
creased. 
As the result of the winter's 
experimentation on this subject 
with a resistance of 1.5 amperes, 
these two curves may be taken 
as representing his muscular re- 
lationship to ergometer II. With 
these curves, therefore, it is per- 
fectly possible to compute the 
total heat output and the energy 
output of the effective muscular 
work and from these values to 
compute the efficiency of the 
subject for the various rates of 
revolution. Such a computation 
of the efficiency would naturally 
be much more satisfactory than 
if it were based upon the re- 
sults for the individual periods 
shown in the tables, since the 
inequalities which occasionally 
appear and which affect the 
general trend of the tabular mat- 
ter, disappear when using the 
curves; it therefore seems ad- 
visable to enter somewhat more 
fully into the discussion of the efficiency of the subject, using the data pro- 
jected in these curves as the basis. 
Relationships between Speed and Efficiency. 
Under these circumstances we may now for the first time intelligently 
consider the relationship between speed and the gross efficiency. It was noted 
in the discussion of table 116 that while the efficiency increased in general 
15.5 
15.0 
14.5 
14.0 
13.5 
13.0 
12.5 
12.0 
11.5 
11.0 
10.5 
10.0 
9.5 
9.0 
8.5 
8.0 
7.5 
7.0 
6.5 
i/ 
< 
v/ 
r/ 
£ 
* 
/ 
J 
r 
A 
'V 
A 
# 
2.50 
2.40 
2.30 
2.20 
2.10 
2.00 
1.90 
1.80 
1.70 
1.60 
1.50 
1.40 
60 70 80 90 100 110 120 130 140 
Fig. 5. — Curves showing the total heat output 
per minute and corresponding external mus- 
cular work per minute, expressed in calories, 
for subject riding with constant load — 1.5 am- 
peres — at varying speeds. 
The revolutions per minute are given at the bottom of the 
figure, the heat output per minute at the left, and the 
effective work performed per minute, expressed in cal- 
ories, at the right. 
