The aim of this research was to examine the characteristics of resistance force (force dependencies on piston displacement) generated by linear hydraulic cylinder type loading units of exercisers acting in different regimes (resistance level and piston velocities). Experimental research of six devices has been performed by means of universal computerized material properties testing machine. The research showed that hydraulic cylinder type loading units of exercise machines generate quite uneven resistance force: depending on acting regime the variation of resistance force reach up to 30% of steady force.

Keywords: hydraulic cylinder, exercise machines, resistance force, piston velocity