118 
MUSCULAR WORK 
chain, with the lower part taut. With a steady load or steady resistance on 
the pedals, the pull on the lower part of the chain would be constant. It 
was noticed, however, that the lower part was frequently slack and that the 
upper part was taut, showing that the subject at times involuntarily over- 
came the inertia of the machine and perhaps contributed slightly to the 
Table 113. — Metabolism experiments without food with subject lying on a couch compared 
with the metabolism in no-load experiments with motor-driven ergometer. (Subject 
M. A. M.; ergometer II.) 
Date. 
Rev- 
olu- 
tions 
per 
min- 
ute. 
No. 
of no- 
load 
peri- 
ods. 
Carbon dioxide per 
minute. 
Oxygen per minute. 
Pulse-rate per 
minute. 
Respira- 
tion-rate 
per 
Ly- 
ing. 
No 
load 
with 
mo- 
tor. 
Increase 
over lying. 
Ly- 
ing. 
No 
load 
with 
mo- 
tor. 
Increase 
over lying. 
Ly- 
ing. 
No 
load 
with 
mo- 
tor. 
Increase 
over lying. 
Ly- 
ing. 
No 
load 
with 
mo- 
tor. 
Amt. 
P.ct. 
Amt. 
P.ct. 
Amt. 
P.ct. 
1912. 
Feb. 13 
Feb. 20 
Feb. 21 
Mar. 8 
Mar. 11 
88 
92 
96 
101 
102 
3 
3 
3 
3 
2 
196 
200 
191 
*205 
215 
502 
503 
565 
611 
669 
306 
303 
374 
406 
454 
156 
152 
196 
198 
211 
233 
247 
236 
2 242 
247 
625 
647 
672 
743 
743 
392 
400 
436 
501 
496 
168 
162 
185 
207 
201 
60 
61 
59 
2 63 
60 
85 
187 
89 
95 
25 
26 
30 
32 
42 
43 
51 
51 
20 
19 
20 
2 20 
21 
23 
19 
1 There was but one record of pulse in each no-load period on this day. 
S This figure is a general average of results with this subject while lying on couch before work in respiration 
experiments without food. (See table 91.) 
movement of the pedals. While the results are reasonably uniform, the 
five experiments being made inside of a month, they doubtless represent a 
larger amount of energy output than would normally be expected from the 
simple friction of the leg. Unquestionably there were slight involuntary 
compensatory movements of the legs, tending to oppose the work of the 
motor at one time and again tending to assist it, and this interplay of mus- 
cles may have caused a not inconsiderable proportion of the total increase 
in the metabolism. While at first sight it would appear as if in such ex- 
periments equilibrium was obtained by the balancing of one leg against the 
other as it went down, the fact that the legs are not in equilibrium has been 
interestingly brought out by Berg, du Bois-Reymond, and L. Zuntz.° 
Unfortunately, the difficulties incidental to the calibration of the ergo- 
meter by means of an electric motor belted to the rear wheel b made it like- 
wise impossible to measure exactly the amount of energy required to drive 
the motor when the legs of the subject were moved freely by the motion of 
the pedals. We believe it especially significant that the professional subject 
M. A. M. found these experiments difficult; consequently, while the results 
obtained with the motor-driven ergometer have been computed and used as 
a base-line, we seriously question whether these values are not considerably 
higher than they should be. If they are too high, the use of them as a base- 
line in computing the increment due to severe work would obviously lead to 
erroneous results. 
Increment in Metabolism Due to a Change in Position from Lying on a Couch 
to Riding on an Ergometer with No Load and No Motor. 
In these experiments the subject sat upon the ergometer in the usual 
riding position, and rotated the pedals by the feet at varying speeds, the only 
" Berg, du Bois-Reymond, and L. Zuntz, loc. cit. 
6 See p. 26 of this report. 
