I.—PHYSIOLOGY. 169 
artificial and extremely laborious ; running at a considerably higher speed 
is much more easy. For longer distances, however, say from 10 miles 
onwards, we have probably in walking the most reliable data available 
for long-continued muscular effort. If we wish to study the exhaustion 
produced by exercise of long duration, walking-men may well provide the 
best subjects for our experiments. 
Skating. 
There remains the top curve of all, that for men skating. The initial 
rise of the curve, due to starting inertia, is very obvious. The fall of 
the curve beyond the maximum is nowhere near so rapid as for the case 
of running. Clearly in skating a man is not able to exert himself with 
the degree of ardour that is possible in the more primitive exercise of 
running. Skill and restraint are necessary, as they are in bicycling: 
there are limits to the output. Moreover, the effort can be continued 
for a long time, at comparatively high speeds. It is interesting to note 
that a man can skate 100 miles at almost the same speed as another man 
can run one mile. The curve falls uniformly throughout as does the walking 
curve. Clearly the phenomena of gradual exhaustion could be well 
investigated in the case of skating. Here again it is obvious which records 
the aspiring athlete should attempt to break. 
Rowing. 
There are only a few records available, and those lying between rather 
narrow limits, for the case of rowing. Taking the case of an eight-oar 
boat, I have been able to obtain very few reliable data. Kennelly gives 
records of crews rowing, for times from 305 to 1,210 seconds. Yandell 
Henderson, in the American Journal of Physiology, vol. Ixxii., p. 264, 
1925, gives five observations made upon the Yale crew of 1924. In addi- 
tion there are records for the Henley course: these, however, are usually 
contaminated by the speed of the water. The most reliable’of the data 
have been plotted in fig. 1 on the same scale as the running, on five times 
the scale of the swimming. The observed points, shown by crosses, are 
somewhat scattered. As far as they go, a mean curve through them 
would lie practically along the curve for women swimming, but of course 
on five times the scale. The interesting part of the curve to the left is 
lacking ; it is obviously impossible to make observations on an eight-oar 
boat for periods of 20 seconds, starting inertia is too great and no result 
of any value could be obtained. It would, however, be of interest to obtain 
data as far back as possible; certainly the records of crews rowing in still 
_ water for a minute andabove should be ascertainable, and they would help 
to fit rowing into the scheme outlined by the other typesof muscular effort. 
Work and Stroke Frequency in Rowing. 
In rowing the movements are slow: in an eight-oar boat, from 30 
to 40 strokes per minute. According to observations by Lupton and 
myself the maximum efficiency of human muscular movement is obtained 
at speeds of about one maximal movement per second. In rowing, 
experience and tradition alike suggest that such a speed is about the 
