The Effects of Cupping on Hamstring Flexibility in College Soccer Players.

College soccer players suffer from hamstring injuries due to inflexibility and repetitive motions involving intense hamstring lengthening and contraction during sport. Although it is a popular intervention for muscular injury, there exists limited evidence of the effects of therapeutic cupping on hamstring flexibility. To determine the effect of cupping therapy on hamstring flexibility in college soccer players. Cohort design. Athletic training clinic. A total of 25, asymptomatic, National Collegiate Athletic Association Division III soccer players (10 males and 15 females; age = 19.4 [1.30] y, height = 175.1 [8.2] cm, and mass = 69.5 [6.6] kg). A 7-minute therapeutic cupping treatment was delivered to the treatment group. Four 2-in cups were fixed atop trigger point locations within the hamstring muscle bellies of participants' dominant legs. Control group participants received no intervention between pretest and posttest measurements. Pretest and posttest measurements of hamstring flexibility, using a passive straight leg raise, were performed on both groups. Passive straight leg raise measurements were conducted by blinded examiners using a digital inclinometer. An independent samples test was used to analyze changes in hamstring flexibility from pretreatment to posttreatment with values set a priori at .05. An independent samples test demonstrated no significant difference in change in hamstring flexibility between participants in the treatment group and those in the control group ( = -.961,  = .35). The findings of this study demonstrated no statistically significant changes in hamstring flexibility following a cupping treatment.