The Immediate Effects of Vibrotexture Shoe Insoles on Quiet Standing Balance and Lower Limb Muscle Activity in Healthy Young Adults.

Abstract

Introduction: Shoe insoles that provide a single source of plantar sensory stimulus, such as texture or vibration, can improve measures of standing balance. Vibrotexture insoles, designed to provide multiple sources of sensory stimuli, may provide greater benefits. This study aimed to investigate the immediate effects of wearing Vibrotexture insoles on quiet standing balance and lower limb muscle activity in healthy young adults.

Methods: Thirty healthy young adults (16 males, 23.6 ± 3.9 years) performed standing balance tests (eyes open/closed, firm/foam surface) wearing four different insoles (vibrotexture, textured, vibrating, and control) within standardized shoes. Balance outcomes included center of pressure (COP) velocity, COP anteroposterior and mediolateral (ML) path length and range. Lower limb muscle amplitude was examined using electromyography at the medial gastrocnemius, soleus, peroneus longus, rectus femoris, biceps femoris, and gluteus medius (dominant leg). Perceived insole comfort and user experience was reported. One-way Friedman tests were used to compare differences between insoles.

Results: For the primary aim of interest, there were no differences in balance measures or muscle activity between the vibrotexture insoles and other insole conditions. Exploratory secondary analyses revealed that COP ML path length was less while wearing the textured compared to vibrating insoles (eyes open, firm surface) (p = 0.022), and rectus femoris muscle amplitude was less while wearing the textured compared to control insoles (eyes open, foam surface) (p = 0.027). The vibrotexture insoles were perceived as less comfortable than the control insoles (p < 0.013). Participants commonly reported the sensory-stimulating insoles to feel "spiky", "tingly", or "rough".

Conclusion: Wearing vibrotexture insoles for the first time does not appear to alter standing balance in young adults. However, textured insoles do alter COP ML path length and rectus femoris amplitude. These findings highlight the need to investigate vibrotexture insoles in more dynamic tasks and in populations with reduced foot sensation, where their effects may be more pronounced.