Simulated isometric contractile properties compared for one-site and three-site model under the assumptions of different cross-bridge stiffness in the range 1.5 to 3.3 pN/nm. (A) Extensive cross-bridge properties (Force, ATP turnover rate and fraction of attached myosin heads) for one site model (filled black symbols) and three site model (red filled symbols). Data normalized to those at a stiffness of 2.8 pN/nm for the one-site model. See Table 1 for absolute values at the latter stiffness level. The ratio between the results for three-site and one-site model indicated by open symbols. (B) Intensive cross-bridge properties (average force per cross-bridge and average strain) normalized as in A. Color coding analogous to that in A.