Stimuli-responsive hydrogels capable of performing work by converting an external stimulation into mechanical motion can be an effective framework for soft actuators. However, most conventional hydrogels are incapable of sustaining external loads. Here, a new approach to create a robust pH-responsive hydrogel is described. This hydrogel is employed to investigate the actuation performance and dynamics of pH-responsive hydrogel actuators under different external loads. The actuation results obtained are then analysed using two different approaches: a thermodynamics approach and a simple mechanical approach.