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Abstract
Cupping is a traditional method for treating pain which is investigated nowadays in clinical studies. Because the methods for producing the vacuum vary considerably we tested their reproducibility.
In a first set of experiments (study 1) four methods for producing the vacuum (lighter flame 2cm (LF1), lighter flame 4cm (LF2), alcohol flame (AF) and mechanical suction with a balloon (BA)) have been compared in 50 trials each. The cupping glass was prepared with an outlet and stop-cock, the vacuum was measured with a pressure-gauge after the cup was set to a soft rubber pad. In a second series of experiments (study 2) we investigated the stability of pressures in 20 consecutive trials in two experienced cupping practitioners and ten beginners using method AF.
In study 1 all four methods yielded consistent pressures. Large differences in magnitude were, however, observed between methods (mean pressures -200±30hPa with LF1, -310±30hPa with LF2, -560±30hPa with AF, and -270±16hPa with BA). With method BA the standard deviation was reduced by a factor 2 compared to the flame methods. In study 2 beginners had considerably more difficulty obtaining a stable pressure yield than advanced cupping practitioners, showing a distinct learning curve before reaching expertise levels after about 10-20 trials.
Cupping is reproducible if the exact method is described in detail. Mechanical suction with a balloon has the best reproducibility. Beginners need at least 10-20 trials to produce stable pressures.