Effects of negative pressure of four-cup cupping therapy on hemodynamic responses of the gastrocnemius

Objective: Previous studies investigating physiological mechanisms of cupping therapy often use a single-cup setting. It is unclear whether these findings could be applied to multiple-cup cupping therapy. The hypothesis is that under 4 cups of stimulation, negative pressure at −225 mmHg would be sufficient to cause a maximal vasodilatory response as −300 mmHg. Methods: Cupping therapy was applied at pressures of −75, −225, and −300 mmHg using a four-cup setup on the gastrocnemius in 12 adults. Muscle hemodynamic responses (oxyhemoglobin, deoxy-hemoglobin, blood volume and oxygenation) were measured using a multi-channel near-infrared spectroscopy on the locations inside the cup (proximal and distal), outside the cup (between cups and distal to distal cup). Two-way ANOVA with repeated measures was used to examine the interaction and main effects of pressure (3 levels) and location (4 levels) factors. Results: The results indicate a significant interaction between negative pressure and location (P < 0.05) and a significant main effect of negative pressure (P < 0.05) and location (P < 0.05) factors on all measures. Post-hoc analysis demonstrated that −300 mmHg causes a significant increase (P < 0.05) in oxyhemoglobin (4.04 ± 0.77 μM as mean ± SE), deoxy-hemoglobin (1.06 ± 0.3 μM), blood volume (5.1 ± 1.02 μM), and oxygenation (2.98 ± 0.59 μM) at the area inside the proximal cup compared to −225 mmHg (2.4 ± 0.33 μM; 0.2 ± 0.28 μM; 2.6 ± 0.42 μM; 2.2 ± 0.45 μM, respectively). Conclusion: The results of this study extend the current research on establishing evidence of a 4-cup cupping on improving muscle oxygenation. These findings also confirm that the effectiveness of cupping therapy is influenced by the applied pressure levels and anatomical locations of the cups, offering new insights into optimizing cupping protocols for musculoskeletal rehabilitation.