. 2015 Aug 3;8:413–421. doi: 10.2147/CCID.S86822

Table 4.

Correlations (Spearman) found between epidermal hydration variables (superficial and deep) and the most relevant biomechanical descriptors obtained in the beginning (T0), after 2 weeks (T1) and in the end (T2) of the study

	T0		T1		T2
	R	P-value	R	P-value	R	P-value
Face
Group 1
Surface hydration
U_f	−0.113	0.489 (ns)	0.005	0.976 (ns)	0.405	0.010^*
U_f – U_a	−0.004	0.980 (ns)	0.382	0.016^*	0.567	0.000^***
U_a/U_f	0.021	0.901 (ns)	0.011	0.945 (ns)	−0.132	0.425 (ns)
Deep hydration
U_f	−0.036	0.835 (ns)	−0.053	0.761 (ns)	0.296	0.071 (ns)
U_f–U_a	−0.038	0.827 (ns)	0.342	0.044^*	0.528	0.001^***
U_a/U_f	−0.096	0.561 (ns)	−0.120	0.466 (ns)	−0.75	0.648 (ns)
Group 2
Surface hydration
U_f	0.722	0.018^*	0.684	0.029^*	0.636	0.048^*
U_f–U_a	0.043	0.907 (ns)	0.394	0.260 (ns)	0.600	0.067 (ns)
U_a/U_f	−0.597	0.068 (ns)	−0.264	0.462 (ns)	−0.851	0.002^**
Deep hydration
U_f	−0.422	0.258 (ns)	0.540	0.133 (ns)	0.576	0.082 (ns)
U_f–U_a	−0.600	0.088 (ns)	0.583	0.099 (ns)	0.709	0.002^*
U_a/U_f	0.273	0.084 (ns)	−0.487	0.153 (ns)	−0.505	0.137 (ns)
Upper limb
Group 1
Surface hydration
U_f	−0.447	0.004^**	−0.060	0.720 (ns)	0.005	0.977 (ns)
U_f–U_a	−0.138	0.394 (ns)	−0.271	0.095 (ns)	0.125	0.460 (ns)
U_a/U_f	0.205	0.200 (ns)	0.347	0.030^*	0.097	0.556 (ns)
Deep hydration
U_f	−0.294	0.086 (ns)	−0.276	0.114 (ns)	−0.014	0.936 (ns)
U_f–U_a	0.006	0.973 (ns)	−0.426	0.011^*	0.381	0.020^*
U_a/U_f	−0.072	0.664 (ns)	0.173	0.292 (ns)	−0.099	0.549 (ns)
Group 2
Surface hydration
U_f	−0.468	0.173 (ns)	−0.721	0.019^*	0.072	0.865 (ns)
U_f–U_a	−0.390	0.265 (ns)	0.188	0.603 (ns)	0.758	0.011^*
U_a/U_f	−0.238	0.508 (ns)	0.131	0.719 (ns)	−0.775	0.008^**
Deep hydration
U_f	−0.157	0.687 (ns)	−0.750	0.020^*	−0.206	0.624 (ns)
U_f–U_a	−0.305	0.424 (ns)	−0.400	0.286 (ns)	0.923	0.000^***
U_a/U_f	0.534	0.112 (ns)	0.467	0.173 (ns)	−0.742	0.014^*
Leg
Group 1
Surface hydration
U_f	−0.373	0.019^*	−0.356	0.028^*	−0.179	0.295 (ns)
U_f–U_a	−0.468	0.002^**	−0.476	0.003^**	0.111	0.511 (ns)
U_a/U_f	−0.165	0.309 (ns)	0.097	0.553 (ns)	−0.109	0.503 (ns)
Deep hydration
U_f	−0.266	0.123 (ns)	0.099	0.578 (ns)	−0.148	0.389 (ns)
U_f–U_a	−0.050	0.765 (ns)	−0.121	0.496 (ns)	0.216	0.199 (ns)
U_a/U_f	−0.049	0.763 (ns)	0.209	0.196 (ns)	−0.173	0.285 (ns)
Group 2
Surface hydration
U_f	−0.292	0.414 (ns)	0.006	0.987 (ns)	0.095	0.824 (ns)
U_f–U_a	−0.455	0.187 (ns)	−0.103	0.777 (ns)	0.723	0.018^*
U_a/U_f	0.315	0.375 (ns)	0.379	0.280 (ns)	0.316	0.374 (ns)
Deep hydration
U_f	−0.496	0.174 (ns)	−0.117	0.765 (ns)	0.176	0.678 (ns)
U_f–U_a	−0.517	0.154 (ns)	−0.200	0.606 (ns)	0.496	0.145 (ns)
U_a/U_f	0.111	0.760 (ns)	0.102	0.779 (ns)	−0.212	0.556 (ns)

Notes:

P<0.05,

^**

P<0.01,

^***

P<0.001.

Abbreviations: ns, not significant; T0, day 0; T1, day 15; T2, day 30; U_f, extensibility; U_f – U_a, the ability of the skin to return to its original state; U_a/U_f, total elasticity (including pulse stretching and recovery); U_r/U_e, elastic function; U_v/U_e, viscoelasticity.