Table 1 Constant parameters and initial values adopted in numerical calculation and the source of the data.

Initial value R _i (t = 7.5mons) (mm)

2.0

Our experiments on over 148 mice

Muscle density ρ _m (gcm^-3)

1.06

[23, 24]

Collagen density ρ _c (gcm^-3)

1.70

[22]

Muscle elastic modulus E _m (Pa)

5.0×10⁴

[28]

Collagen elastic modulus E _c (Pa)

3.2×10⁷

[29, 30]

Poisson' ratio v

0.47

[31]

Time step h (hrs)

3