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Table 1 Isometric contractile properties of extensor digitorum longus muscles from four-month-old mdx and mdx-TG mice

From: Transgenic overexpression of γ-cytoplasmic actin protects against eccentric contraction-induced force loss in mdx mice

Contractile properties

mdx(n= 6)

mdx-TG (n= 6)

P value

EDL mass (mg)

15.8 ± 0.8

13.7 ± 0.5

0.043*

Lo (mm)

11.9 ± 0.2

12.2 ± 0.1

0.205

CSA (cm2)

0.028 ± 0.001

0.024 ± 0.001

0.009*

Passive stiffness (N/m)

19.6 ± 1.6

14.2 ± 0.9

0.018*

Active stiffness (N/m)

714.8 ± 40.1

738.7 ± 98.3

0.826

Pt (mN)

59.6 ± 5.6

65.7 ± 8.1

0.593

TPT (ms)

17.9 ± 0.4

18.3 ± 0.4

0.556

RT1/2 (ms)

21.4 ± 1.3

19.1 ± 0.7

0.161

Specific Pt (N/cm2)

2.1 ± 0.2

2.8 ± 0.4

0.153

Po (mN)

264.0 ± 21.5

288.6 ± 39.1

0.593

+dP/dt (N/s)

7.15 ± 0.63

7.68 ± 0.95

0.648

-dP/dt (N/s)

10.9 ± 1.2

13.0 ± 2.4

0.458

Specific Po (N/cm2)

9.1 ± 0.6

12.2 ± 1.8

0.140

  1. Values are means ± SEM. CSA = cross-sectional area; +dP/dt = maximum rate of tetanic force development; -dP/dt = maximum rate of relaxation; EDL = extensor digitorum longus; Lo = optimal length; Po = peak tetanic force; Pt = peak twitch force; RT1/2 = one-half relaxation time; TG = transgenic; TPT = time to peak twitch force. *Statistically significant difference from mdx.