Article Figures & Data
Figures
- Figure 1.
Torques on the vertebrae of the neck and lower back due to neck flexion and trunk flexion.
Circles indicate the approximate center of mass of the head and trunk. Arrows represent the force of gravity vectors (weight) of the head (WH) and trunk (WT).
A: Approximately neutral alignment with the force vectors acting through the spine.
B: Demonstrates neck flexion (θH). The weight of the head produces a torque proportional to the perpendicular distance from the axis of rotation (RH).
C: Demonstrates trunk flexion(θT). The weight of the trunk produces a torque proportional to the perpendicular distance from the axis of rotation (RT).
- Figure 2.
Group mean activity of the cervical erector spinae (CES) muscle as a percentage of maximum voluntary contraction is plotted for five different neck flexion angles
Error bars indicate one standard deviation. The 0° neck flexion condition was significantly different from all other neck flexion conditions
- Figure 3.
Group mean activity of the upper trapezius (UT) muscle as a percentage of maximum voluntary contraction is plotted for five different neck flexion angles.
Error bars indicate one standard deviation. The 0° neck flexion condition was significantly different from the 30° and 40° neck flexion conditions.
- Figure 4.
Group mean activity of the thoracic erector spinae (TES) muscle as a percentage of maximum voluntary contraction is plotted for five different trunk flexion angles.
Error bars indicate one standard deviation. The 0° trunk flexion condition was significantly different from the 20°, 30°, and 40° trunk flexion conditions.
- Figure 5.
Group mean activity of the iliocostalis lumborum (IL) muscle as a percentage of maximum voluntary contraction is plotted for five different trunk flexion angles.
Error bars indicate one standard deviation. The 0° neck flexion condition was significantly different from the 30° and 40° neck flexion conditions.
Tables
- Table I.
Anthropometric neck torque (TH) computed for five different neck flexion angles (θ).*
- Table II.
Anthropometric lower back torque (TH&T) computed for five trunk flexion angles (θ)*
