Background/Purpose: The patellofemoral pain syndrome (PFPS), which might be caused by weakness and delayed activation of the vastus medialis obliquus (VMO), as well as tightness of the vastus lateralis (VL), gravely affects daily lives and exercises. Kinesio tape (KT) are often used to prevent and treat musculoskeletal diseases. Different application directions and tension levels can produce a promoting or inhibitory effect. If KT could improve the symptoms of PFPS through coordinating imbalanced muscles, it has positive significance. This study aimed to explore the effects of three KT application methods on PFPS and compare them with placebo, to explore possible psychological effects. Method: Fourteen participants with PFPS (7 males, 7 females, Mage = 20.71) were recruited from Beijing Sport University. A repeated-measures pre-test/post-test design was used in this study. Each participant completes all four methods (VMO facilitatory, VL inhibitory, VMO facilitatory & VL inhibitory, white placebo tape) with a washout period of one week considered between each two methods. Before applications of KT, participants accept tests such as EMG (Delsys), proprioception (PK254), static balance (one foot standing test), and pain (VAS), and are immediately retested after applications. MATLAB 7.13 (MathWorks Inc., Natick, MA, USA) is used to analyze EMG data, and SPSS 25 (IBM Corp., Armonk, NY, USA) was used for statistical analysis, with P < 0.05 set to determine statistical significance. Results: The results manifested that after using VMO facilitatory KT, the static balance is significantly improved (18.752 ± 29.693, P = 0.002), and the mean VL activity was significantly reduced (2.837 ± 1.532, p = 0.048). After applying VL inhibitory KT, there was a great improvement in proprioception (2.666 ± 2.272, p = 0.048) and an increase in the average activation level of VMO (0.300 ± 0.070, P = 0.036). All four methods greatly reduced the VAS score of pain (PVMO = 0.002, PVL = 0.001, PVMO & VL = 0.001, Pplacebo = 0.005). The improvement effect of VMO facilitatory KT was significantly superior to the other three methods (PVMO-VL < 0.001, PVMO-VMO & VL < 0.001, PVMO-placebo < 0.001). There was no distinct difference in terms of the effect of the other three methods. The difference before and after any other indicator was not obvious. Conclusion: Consistent with previous literature, our study supported that KT can enhance functional levels and alleviate symptoms, which has practical significance for the prognosis of PFPS and early return to exercises. However, the comparison with placebo also displays that some of the effects of KT may be attributable to psychological effects, rather than physiological or mechanical mechanisms. Therefore, in the future, larger sample sizes should be considered and more variables could be restricted to explore the issue.
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