114 MUSCULAR WORK 
In computing the results obtained with a brake ergometer, such as the 
Gartner ergostat, still another method has been used for finding the net 
efficiency as it is customary to deduct from the total energy output during 
work the energy output required to turn the ergostat the same number of 
revolutions without external friction. Various other methods of computation 
have suggested themselves to different writers, with a consequent lack of 
uniformity in the base-lines used. The difficulties incidental to the computa- 
tion of the results obtained during mountain-climbing and marching are also 
found in connection with our bicycle ergometer experiments, but, as has pre- 
viously been pointed out, an attempt has been made to secure as many base 
lines as possible. Unquestionably some of these base-lines are wholly ficti- 
tious and their use in the computations is not justifiable. On the other hand, 
with all the possible combinations and conditions, it is more than probable 
that certain of these calculations do indicate truly the increased metabolism 
incidental to a measured amount of external muscular work. It is our pur- 
pose to recognize these various base-lines, and use them, so far as possible, 
in computing the results of our experiments. 
Confining ourselves for the moment exclusively to the question of the 
method to be used in computing the results obtained in experiments with 
the bicycle ergometer, it can be seen that not only may we deduct the metab- 
olism for the equivalent period when the subject is lying quietly in bed, but 
we may also deduct the metabolism incidental to sitting quietly upon the 
bicycle without rotating the pedals. This is an upright position that must 
be assumed by the subject before work can be begun and which calls for an 
increased metabolism over the lying position. The work incidental to this 
can not be measured on the ergometer; indeed, it is doubtful if there is any 
measurable external muscular work performed, although sustaining the body 
in an upright position does call for a considerable increase in internal muscular 
work. 
Furthermore, in rotating the pedals, there is a movement of the legs 
with consequent muscular work which, for the want of better phraseology, 
may be termed the internal friction of the legs. A value may be obtained for 
this activity and used as a base-line by rotating the wheel of the bicycle by 
means of an electric motor, so that the legs are made to move up and down as 
in riding while no actual work is done upon the ergometer itself. Although 
the ergometer has but little friction, considerable internal work of the leg- 
muscles is required in rotating the wheel of the ergometer, even when no 
current is passed through the magnet; hence in computing one of the various 
grades of efficiency the energy output incidental to rotating the ergometer 
under these conditions may properly be deducted from the total energy out- 
put, thus forming a third base-line. 
Even though measurable, the friction of the ergometer is so small in 
amount that it would not justify a computation based upon the ground that 
overcoming the friction of the bicycle requires a given amount of external 
muscular work. The efficiency of the body in performing a very small amount 
of work may be studied, however, by using a slight measurable brake-effect 
upon the wheel. The amount of work thus done is so small in comparison 
with the total metabolism of the body that it may be classed with such 
minor muscular movements as the moving of a fan back and forth or rocking 
