Frozen shoulder is a disease characterized by shoulder pain and limited range of motion. Conservative treatment is preceded by surgical treatment to reduce pain and recover range of motion. Hydraulic distention is a procedure in which a sufficient amount of solution is injected into the shoulder joint to rupture the rigid joint capsule. Recently, the method of continuously maintaining the expanded capsular state after injection without the process of rupturing the rigid joint has also been used. However, in order to obtain the maximal stretching effect, we proposed a ‘pumping technique’ that inflates and shrinks the rigid joint capsule by repeating the process of infusion and regurgitation of the injection fluid into the capsule. Our proposed ‘pumping technique’ was shown to be more effective in increasing range of motion than the conventional hydraulic distension. This ‘pumping technique’ can be suggested as an effective therapeutic option for frozen shoulder.