The Hydraulic Infinite Linear Actuator, HILA, has been presented in previous publications. The novel actuator consists of one, two or more double-acting cylinders witha common piston rod and hydraulically detachable pistons. In the basic gait, one cylinderalternatingly engages and drives the load while the other retracts. The HILA thus works in akind of rope-climbing motion. The concept also allows other gaits, i.e. patterns of motion.This contribution focuses on the ballistic gait, a pattern of motion where one cylinder engagesto give the load a push. The load then carries on with its motion by inertia, cylinders disen-gaged. The actuator thus realizes hydro-mechanical pulse-frequency modulation (PFM).This gait is energy efficient and able to recuperate energy.