Does elastic taping on soles improve flexibility? A randomized controlled trial with equivalence test design.

Background: Elastic taping that applies shear force affects joint movement. However, it remains uncertain whether elastic taping or stretching is more effective in improving flexibility.

Objective: We investigated whether elastic taping for flexibility improvement is comparable to traditional stretching.

Methods: In this randomized controlled trial, 64 university students were randomly allocated to two groups: elastic taping on the sole or 30 s of static stretching. The primary outcome measures were the straight leg raising angle, tested with an equivalence margin (± 9.61∘ on changes), and the fingertip-to-floor distance. Secondary outcomes were the hip flexor and knee extensor strength, two-step distance, adverse events, and pain intensity during the intervention, which were compared using conventional statistical methods.

Results: The mean differences in straight leg raising between the two groups after the interventions were not greater than the equivalence margin (mean [95% CI]: 1.4 [-6.9, 9.5]; equivalence margin, -9.61∘ to 9.61∘). There were no consistent differences between groups in terms of secondary outcomes except for pain intensity during the intervention (p> 0.05). Elastic taping did not induce pain.

Conclusion: Elastic taping augments the flexibility-improving effect comparable to static stretching, based on an equivalence margin. Elastic taping of the sole appears to be an alternative method of improving flexibility.