a and b, Snapshots of cell membranes making invasive protrusions into a matrix with a, high and b, low plasticity. Scale bars indicate 10 μm. Spheres indicate cross-linkers bearing forces higher than 60 pN. Color scaling represents level of forces acting on fibers and cross-linkers. c and e, Strain in a matrix during cell protrusions with a total force of 1 nN at t = 0–1 hour, and during an unloaded recovery phase of t = 1–1.3 hours, with different values of c, the zero-force unbinding rate constant (k0,u) and e, the force sensitivity (λu). d and f, Maximum and permanent strains depending on d, k0,u and f, λu. k*0,u = 3 ×10−6 s−1 and λ*u = 100 pm are reference values.