Fig 1.
Active movements investigated: (a) human kneeling flexion (b) human kneeling extension (c) human standing flexion (d) human standing extension (e) sheep flexion (f) sheep extension.
Fig 2.
Human participant in four-point kneeling (a) and sheep (b), showing marker locations.
Fig 3.
Vector orientations used to calculate spinal angles.
Fig 4.
Mean (standard deviation as error bars) of range of motion in degrees between adjacent vertebral segments during flexion (a) and extension (b) in sheep and human participants in an upright (UR) and four-point kneeling posture (KN).
Brackets and asterisks indicate significance differences (*p<0.05, **p<0.001) between humans and sheep.
Fig 5.
Examples of raw (top images) and filtered (lower images) EMG signals of the muscles erector spinae left (ESL), erector spinae right (ESR), rectus abdominis left (RAL), rectus abdominis right (RAR), obliquus externus left (OEL), obliquus externus right (OER), obliquus internus left (OIL), and obliquus internus right (OIR) with accompanying z-displacement of the 11th (human) or 12th (sheep) thoracic marker for flexion in a mature human participant in kneeling (left), and a mature sheep (right).
Table 1.
Medians of the muscle activity of erector spinae left (ESL), erector spinae right (ESR), rectus abdominis left (RAL), rectus abdominis right (RAR), obliquus externus left (OEL), obliquus externus right (OER), obliquus internus left (OIL), and obliquus internus right (OIR) as a percentage of the maximally observed EMG (%MOE) in humans in kneeling (KN) and upright (UR) postures and in sheep for extension (E) and flexion (F) movement.
P-values indicate between species significant differences for human kneel vs sheep, and human upright vs sheep conditions. Non-significance is indicated by NS.
Table 2.
Medians with lower and upper quartiles in parentheses of the Flexion-Extension Difference (FED) between the abdominal muscles and spinal extensor in sheep and in humans in a kneeling (KN) and upright (UR) posture during flexion and extension.
A positive value indicates greater abdominal activity. Identical superscripts indicate significant differences between sheep and human conditions.
Table 3.
Mean and standard deviation (stdev) of skin displacement in mm of the markers overlying the sacrum and the spinous processes of L5, L2, T12, T8, and T5.
Data from all three sheep is presented except for the marker over T12, which is only available from one sheet.