A method of determining performance characteristics and/or internal structural features of hyperelastic polymer materials includes performing at least one macro-level loading experiment on a sample comprised of a given composition. From the macro-level loading experiment, a set of internal structural features are determined. More particularly, tensile and compressive uniaxial loading data is collected and fit with a stress-strain function being a ratio of two polynomials. A curve fit analysis yields a set of coefficients relating the uniaxial loading data to the stress-strain function. From these coefficients, a set of statistical parameters are calculated, yielding information about internal microstructural features of the polymer composition, and therefore, performance characteristics of a part comprised of the given polymer composition.