(a) Cell attached to microposts represented by a one-dimensional contractile element connected to two elastic springs. (b) Scaled stress σ/|σ*|, (c) scaled contractility ρ/|ρ*| and (d) scaled total energy as functions of scaled post stiffness Kp/K with β(4 < βK < 6) and α(2 < αK < 3). All the parameters (α, β, K) are satisfied by the stability criterion. Here σ*, ρ* and are the values for βK = 4, αK = 2 and . (Online version in colour.)