Fig 1.
Mean stance phase joint kinematics for the 3 participant groups: younger (dashed black), middle-age (dashed grey) and older (solid grey).
An overall study population mean of the stance phase kinematics is also illustrated solid thick black).
Fig 2.
Waveforms were reconstructed using the maximum and minimum PC scores.
The far left column illustrates the principal components that represent a specific pattern of deviation from the mean trial vector (i.e. waveforms) and the right four columns illustrate nature of those deviations from the mean waveform (solid line) based on the maximum and minimum PC scores. Our interpretation of the nature of these deviations is listed in Table 2.
Table 1.
The mean and SE of the PC scores that were significantly different between age-groups Younger (Y), Middle-age (MA) and Older (O).
Table 2.
The interpretation of those deviations from the mean knee function represented by each PC illustrated in Fig 2.
Fig 3.
Data reconstructed for the young and middle aged groups using the average scores and PC1, PC3, and PC6.
The middle-aged adults had a more abducted knee throughout stance, less tibia external rotation at heel strike and greater tibia internal rotation through middle and late stance, and greater tibia anterior translation in early stance but less anterior translation at terminal stance.
Fig 4.
Data reconstructed using the average scores for PC2 and PC5.
The older adults had less knee abduction in late stance and a smaller difference in the knee abduction magnitude between early and late stance local minimums. There was also a significant difference in the tibial internal-external rotation and AP translation throughout stance. The older adults tended to have more internally rotated and more anteriorly translated tibias relative to femurs throughout the stance phase.