Table 2b:

Parameters of tissue microstructure for young and senior participants from the RPBM model fit to λ₃

fit parameters	young	senior
$D_0$ [μm2/ms] free diffusion	1.83 ± 0.16	1.88 ± 0.18
${\zeta }^{\ast }$* volume fraction	3.75 ± 1.18	2.61 ± 0.39
$S∕V$ [μm−1] surface to volume ratio	0.26 ± 0.06	0.21 ± 0.13
$\kappa$ [μm/ms] permeability	0.03 ± 0.01	0.04 ± 0.03
$a$ [μm] myofiber diameter	16.57 ± 4.11	22.31 ± 8.01
$l$ [μm] effective thickness	30.67 ± 9.59	29.92 ± 13.08
${\tau }_R$ [ms] residence time	292.0 ± 138.3	418.6 ± 282.1
${\tau }_D$ [ms] † dwell time	80.7 ± 39.8	152.4 ± 93.7

^*Significant difference between young and senior age groups ( p < 0.05)

^†Trend towards significant difference between young and senior age groups ( p < 0.1).