This paper presents results of measurements of pressure and strain in blades of a VVN2-50 liquid piston rotary compressor (LRC). The rotor of the compressor is described. Strains from centrifugal forces were measured with rotation of the rotor in nominal regimes without liquid. A compensating resistor, acting as a strain gage, was glued to the cover of the hole in the outlet manifold to provide for automatic compensation of temperature changes. The distribution of maximum stress intensity on the concave side of the blade is shown. The first experiment conducted under service conditions showed that the blades of a liquid-piston pump experience complex loading under conditions of high-speed liquid flow. Such a study is necessary to ensure adequate strength in smaller-volume blades of variable thickness that have been proposed to further improve pump designs. Together with a decrease in material content and unit electric power consumption, this modification will increase the productivity of liquid-piston pumps in both the pump and the compressor regimes.