Muscles that Raise the Body in Climbing
The leg sinew and the effort of lifting a man aloft, with a weight on an inclined plane
The sheet pairs a mechanical maxim with a study of how the body raises itself. A diagram of a weight on an inclined plane carries the note that every weight moves of its own accord, and a small figure of a man climbing a step illustrates the action. The long passage in the lower half analyses the sinew joined to the kneecap that straightens the leg and the muscle that opens the angle between thigh and trunk, arguing which has the harder task in lifting the body.
On this page
Weight on an inclined plane
A weight rests within a quarter-circle diagram against an inclined line. The accompanying note states the general principle that every weight moves of its own accord, framing the study of effort and lifting on the rest of the page.
The sinew and muscles that raise the body
Leonardo reasons that the sinew joined to the kneecap, which straightens the leg, meets more effort in raising the man the more the leg is bent. The muscle that opens the angle the thigh makes with the trunk has an easier task and lifts less weight, since it is spared the weight of the thigh and is served by the better muscles that form the buttocks.
Man climbing a step
A sketchy figure of a man's crouched lower body climbing a step accompanies the note, illustrating in the flesh the biomechanical effort of raising the body that the passage analyses.