Elucidation of The Effect of Flossing on Improving Joint Range of Motion.

Flossing has been hypothesized to improve joint range of motion (flexibility), potentially through enhanced fascial gliding, although this mechanism remains speculative. This study aimed to clarify the effect of flossing, a new type of myofascial release, on joint range of motion by focusing on tissue gliding properties. This study involved 14 healthy participants (aged 18-25 years) who performed two types of active exercises with floss bands wrapped around their lower legs. As a control, the participants performed the same active exercises on different days without floss bands. Measurements taken before and after the intervention included ankle dorsiflexion range of motion, ankle plantar flexion maximum voluntary contraction, medial head of the gastrocnemius muscle thickness using ultrasound, and fascial hardness at five locations according to depth. Lower leg flossing significantly increased ankle dorsiflexion range of motion by 28.3 ± 19.9% (control: 14.6 ± 12.4%, P = 0.04, d = 0.83). No significant changes were observed in maximum voluntary plantar flexion contraction or overall muscle and fascial hardness. However, the rate of change in hardness showed a trend toward reduction in the superficial fascia and the upper and middle gastrocnemius muscles, with the upper gastrocnemius muscle exhibiting a statistically significant decrease in hardness (P = 0.05). Flossing showed trends toward reducing superficial muscle and fascial hardness, particularly in the superficial fascia and the upper gastrocnemius muscle, although not all changes were statistically significant. This suggests that potential improvements in intertissue gliding around the fascia could contribute to an increased range of motion.