Graphics Reference
In-Depth Information
Human Musculature
In humans, most limb muscle contains a roughly equal amount of slow-
twitch and fast-twitch fibers, though they are not evenly distributed. The
muscles of the back contain far more slow-twitch fibers than fast-twitch
fibers. The average adult male body is made up of 42% skeletal muscle; the
average adult female is made up of 36% skeletal muscle as a percentage of
total body mass.
FIG 5.3
Human musculature.
Neck and Shoulders
Both the neck and shoulder are capable of independent movement, but they
often work in tandem in a given action. In addition to movement along the
sagittal and transverse planes, the neck is capable of a degree of rotational
