Table II.
Summary of Physiologic Studies
| EDL | Diaphragm | |||||||
|---|---|---|---|---|---|---|---|---|
| IIb+/+ | IIb−/− | IId+/+ | IId−/− | |||||
| Twitch properties | ||||||||
| CT (ms) | 34.2 ± 1.8(6) | 38.0 ± 3.2(7) | 61.9 ± 4.9(8) | 80.7 ± 5.7(8)* | ||||
| RT1/2 (ms) | 47.4 ± 5.2(6) | 69.6 ± 9.8(7)* | 103.6 ± 9.9(8) | 154.4 ± 15.5(8)* | ||||
| Pt(kN.m2) | 91.4 ± 11.5(5) | 40.9 ± 6.7(6)* | 15.4 ± 3.5(7) | 23.1 ± 6.7(8) | ||||
| Tetanic properties | ||||||||
| P0(kN.m2) | 262.8 ± 20.6(5) | 138.2 ± 27.9(6)* | 42.6 ± 9.6(7) | 53.4 ± 11.4(8) | ||||
| Fusion frequency (Hz) | 76.7 ± 2.1(6) | 70.0 ± 3.1(7) | 58.8 ± 2.3(8) | 58.8 ± 4.0(8) | ||||
| Tw/Tet | 0.30 ± 0.02(6) | 0.31 ± 0.11(7) | 0.35 ± 0.04(8) | 0.39 ± 0.06(8) | ||||
| +dP/dt* 1/Pmax | 5.45 ± 0.24(6) | 5.32 ± 0.58(7) | 5.2 ± 0.7(7) | 3.4 ± 0.3(8)* | ||||
| −dP/dt* 1/Pmax (ms-1) | 7.98 ± 0.38(6) | 4.76 ± 0.46(7)* | 2.9 ± 0.5(7) | 2.0 ± 0.2(8) | ||||
| K R (s−1) | 34.4 ± 2.0(6) | 24.0 ± 3.5 (7) | 14.4 ± 0.3(7) | 10.1 ± 1.0(8)* | ||||
Values are mean ± SEM (n). Asterisks indicate significance at P < 0.05. CT is contraction time calculated as time to peak twitch tension, RT1/2 is one-half relaxation time, Tw/Tet is twitch to tetanus force ration, K R is rat constant for relaxation, +/− dP/dt are peak positive and negative rates of change of tension normalized to maximum tetanic force. P0 is peak tetanic tension and Pt is peak twitch tension, both normalized per cross-sectional area.
*
Indicates statistical significance of P < 0.01.