Muscle fascicles in pennate muscles lie at an angle to the line of action of the muscle. When pennate muscles contract, the fascicles rotate as well as shorten, increasing the gear ratio of the whole muscle. Current pennate muscle models have added the effects of changes in muscle thickness (i.e. bulging) to the traditional planar models, demonstrating that muscle bulging can increase the architectural gear ratio (AGR) of pennate muscles as well as enable variable gearing under variable loading conditions. Most analytical models of muscle architecture assume that the fascicles start in a planar configuration and remain in that plane during muscle contraction, and they also assume straight, rather than curved, fascicles. Here, we introduce new models to demonstrate that these assumptions mask the impact of whole-muscle shearing and changes in fascicle curvature on AGR. These new analytical models lead to a generalized principle of dynamic architectural gearing in whole muscles: any deformation of a muscle that does not occur along the line of action, yet causes the muscle fascicles to lengthen along the line of action, will increase AGR. Conversely, any orthogonal deformation that causes the muscle fascicles to shorten along the line of action will decrease AGR. Whole muscle torsion can be added to the list of deformations that likely affect AGR, along with bulging, shear, and changes in fiber curvature, all of which can happen at the same time. To model real-world muscle contraction, this principle could be applied iteratively throughout the 3D volume of muscles with complex fascicle architectures to develop finite element models for AGR and variable gearing.