The impact of the gel stiffness on the (a) net cellular force and (b) total strain energy in the hydrogel matrices. Results are shown for NL-CUR, LIN, and NL-REF. For each gel stiffness, three cells are considered, as depicted by different symbols (dot, square, or asterisk). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)