Fig 1.
Scatterplot of handgrip strength as a function of age, separately for Maasai men (left) and women (right).
Cut-off points for the two age groups included in the shape analysis are indicated with vertical, dashed lines. The curved line is the quadratic regression of physical strength on chronological age (men: R2 = 0.10, n = 183; women: R2 = 0.14; n = 118).
Table 1.
Correlations (Spearman rs) of handgrip strength with age within age-sex groups.
Table 2.
Test statistics for the association of handgrip strength with facial shape scores within age-sex groups.
Fig 2.
Visualization of the association of handgrip strength (HGS) with the corresponding facial shape scores within age-sex groups.
The test statistics related to the depicted regression lines are given in Table 2. The association is significant in all sex-age groups, but stronger for women and young men than for mid-adult men.
Fig 3.
Facial shape correlates of handgrip strength (HGS) in the Maasai.
Thin-plate spline deformation grids (on the left) depict the facial shape changes with HGS as deformations from the average facial configuration (middle column) to −5 SD of HGS (left column) and to +5 SD (right column), separately for each sex-age group. This magnification factor was applied to facilitate interpretation. The same facial configurations were also visualized through image unwarping and averaging (on the right). Thin-plate spline deformation grids and facial morphs were aligned at the height of the pupils and scaled for interpupillary distance.