The Combined Effect Of Communication, Expectations, And Percussive Therapy On Acute Hamstring Flexibility In Healthy Subjects

The power of suggestion in healthcare is a significant and growing area of research. Patient expectations have been shown to impact patient outcomes such as pain intensity, level of function, and health-related quality of life. While common placebo treatments often include sham medications or treatments, the way in which a health care provider communicates with a patient may also bring about a positive response that is independent of any specific treatment. PURPOSE: The purpose of this study is to gather the first data on the acute effect of clinician communication and percussive therapy on hamstring flexibility in young and healthy individuals. METHODS: Twenty subjects (8 females, 12 males, mean age 23.2 ± 1.5 years) participated in this study. Subjects were randomly assigned to one of two groups: The Intervention group received a singular treatment of percussive massage targeting the subject’s dominant hamstrings combined with a pro-percussion communication session on its effects and benefits, while the Control group received a comparable 5-minute percussive massage treatment to the subject’s dominant hamstrings combined with a neutral-percussion communication session devoid of any discourse pertaining to percussive therapy. Hamstring flexibility and subject expectations were measured prior to and immediately following the intervention. RESULTS: There was a significantly greater increase in hamstring flexibility in the intervention group (mean change = 9.5 degrees; SD = 2.46) as compared to the control group (mean change = 4.1 degrees; SD = 3.7; t = 3.47; df = 9; p = .002) with a large effect size (1.7). Expectations for improvement in the intervention group increased (mean change = .41, SD = .46) as compared to the control group (mean change = 0; SD = 0), however, the difference between groups was not significant (p = .07). A Spearman’s correlation analysis revealed no apparent relationship (r = .22) between changes in hamstring flexibility and changes in expectations. CONCLUSIONS: This study offers the first data supporting the use of positive communication during the application of percussion therapy in improving hamstring flexibility. The findings of this study underscore the importance of the relationship between healthcare provider communication and positive outcomes.