Figure 5. Reduced specific force in aged skeletal muscle associates with blunted [Ca²⁺]_o dependence.

(A) Maximal tetanic force normalized to the cross sectional area in young (red) and aged (green) EDL muscles (n = 12, * p < 0.001). (B) Intact EDL muscle from aged mice subjected to the same protocol as in Figs 2-3, demonstrates that NiCl₂ lacks an effect in aged muscle. (C) Summary data for the effects of NiCl₂ and washout after treatment (n = 8). (D) Summary data for the effects of 0[Ca²⁺]_o and washout after treatment (n = 6).