The concentrations of free Ca²⁺ required for half-maximal force (EC₅₀) and the maximal Ca²⁺-activated force per cross-sectional area (Fmax) for three surgery groups under varying experimental conditions.

<p>Data are presented as average ± S.E.M.</p><p>*: denotes <i>P</i><0.016 compared to perfused fibers under identical experimental conditions.</p><p>†: denotes <i>P</i><0.016 compared to perfused and reperfused fibers under identical experimental conditions.</p><p>‡: denotes <i>P</i><0.016 compared to perfused and ischemic fibers under identical experimental conditions.