Table 1.

Fatigability in force reduction of mouse soleus muscle after unloading and during postfatigue recovery

	Fatigue (% of Fo) at 450 s	Recovery (% of Fo) at 1 min
CON	53.00 ± 1.19	81.57 ± 1.49
HU	36.96 ± 3.31a	72.52 ± 1.38a
3DR	29.66 ± 2.75a	63.41 ± 2.64ab
7DR	26.06 ± 1.35ab	66.05 ± 1.14a
15DR	21.96 ± 1.96ab	66.78 ± 1.84a
30DR	33.59 ± 2.05a	72.51 ± 2.09ac
45DR	45.87 ± 1.60cdef	75.37 ± 1.65ede
60DR	51.67 ± 2.58cdefg	80.18 ± 1.56ede

Values are presented as means ± SE. Soleus muscle fatigue and postfatigue force recovery were calculated as the percentage of peak tetanic force at optimal muscle length (F_o). The force reduction at the end of fatigue treatment and the 1st minute after fatigue force recovery were compared in control mice (CON), mice with 4 wk of hindlimb unloading (HU), and those during 3–60 days of reloading (DR). The results showed that the fatigability and postfatigue force recovery were worsened to become lower than HU level at 3–15 days of reloading and gradually improved to the control level at 30–60 days reloading. n = 9 in CON, n = 4 in HU, n = 7 in 3DR, n = 6 in 7DR, n = 4 in 15DR, n = 8 in 30DR, n = 7 in 45DR, and n = 5 in 60DR.

^aP < 0.05 vs. CON,

^bP < 0.05 vs. HU,

^cP < 0.05 vs. 3DR,

^dP < 0.05 vs. 7DR,

^eP < 0.05 vs. 15DR,

^fP < 0.05 vs. 30DR,

^gP < 0.05 vs. 45DR. Statistical analysis was performed using 1-way ANOVA with mean comparison with Tukey's test.