Contraction in myocardial tissue is the result of a complex process through which chemical energy on the cellular level isconverted into the mechanical energy needed to circulate blood throughout the body. Due to its vital role for the organism,myocardial contractility is one of the most intensively investigated subjects in medical research. In this contribution, wesuggest a novel phenomenological approach for myocardial contraction that is capable of producing realistic intracellularcalcium concentration (ICC) and myocyte shortening graphs, can be easily calibrated to capture different ICC andcontraction characteristics and, at the same time, is straightforward to implement and ensures efficient computer simulations.This study is inspired by the fact that existing models for myocardial contractility either contain a number of complexequations and material parameters, which reduce their feasibility, or are very simple and cannot accurately mimic reality,which eventually influences the realm of computer simulations. The proposed model in this manuscript considers first theevolution of the ICC through a logarithmic-type ordinary differential equation (ODE) having the normalized transmembranepotential as the argument. The ICC is further put into an exponential-type ODE which determines the shortening of themyocyte (active stretch). The developed approach can be incorporated with phenomenological or biophysically basedmodels of cardiac electrophysiology. Through examples on the material level, we demonstrate that the shape of the ICC andmyocardial shortening curves can be easily modified and accurately fitted to experimental data obtained from rat and mousehearts. Moreover, the performance of the model in organ level simulations is illustrated through several multi-field initialboundary value problems in which we show variations in volume-time relations, heterogeneous characteristics of myocardialcontraction and application of a drug in a virtual left ventricle model.