Fig. 2. Comparison of the effects of halothane in adult and senescent rats on isometric active force normalized per cross-sectional area (AF), at a calcium concentration of 0.5 (A ; adult n = 12, senescent n = 12) or 1 mm (B ; adult n = 8, senescent n = 6). Concentrations are reported in vol%. Data are mean ± SD. P values refer to between-group differences. NS = not significant. *=P < 0.05 versus baseline values.