The effects of foot orthoses and sensory facilitation on lower limb electromyography: A scoping review

Immediate Effects of Custom Foot Orthoses on Postural Balance and Pain in Obese Middle-Aged Women With Plantar Fasciitis

Given the prevalence of plantar fasciitis (PF) among middle-aged women, we investigated the immediate impact of custom foot orthoses (CFO) on pain and static and dynamic postural balance, addressing a critical gap in understanding the potential benefits of CFO in managing PF-related pain and postural instability. Nine middle-aged women with PF and obesity were evaluated for pain levels and center of pressure (CoP) values in bipedal, unipedal with a non-affected foot, and unipedal with an affected foot on the Timed Up and Go (TUG) test, while they were barefoot, wearing standard insoles (SI), and wearing CFO. We found that CFO significantly and immediately reduced pain (p < .01) improved CoP values (p < .01) in the unipedal stance with the affected foot, and enhanced TUG test scores (p < .001). The results demonstrated a significant (p < .01) improvement in CoParea values and TUG test scores with CFO, compared to SI. These findings underscore the immediate benefits of CFO in alleviating pain and improving postural balance in obese middle-aged women with PF, highlighting their potential as a valuable intervention.

Effects of textured insoles on dynamic balance and ankle muscle activity in soccer players with and without chronic ankle instability

BACKGROUND

Chronic ankle instability (CAI) poses challenges in sports. Textured insoles (TI) are a promising intervention for enhancing dynamic balance in CAI athletes. This study aimed to investigate the effects of TI on dynamic balance performance and ankle muscle activity in soccer players with and without CAI.

METHODS

Thirty-eight soccer players (19 CAI, 19 non-CAI) participated. Participants performed a modified star excursion balance test (mSEBT) while wearing TI and standard insoles (SI). The %SEBT reach distance and electromyography (EMG) activity of tibialis anterior (TA), medial gastrocnemius (MG), and peroneus longus (PL) were measured during maximum reached in each direction of the mSEBT.

RESULTS

No significant effects or interactions were found between ankle conditions (CAI vs. non-CAI) or insole types (TI vs. SI) on %SEBT reach. However, CAI players showed greater MG activity in posteromedial and posterolateral direction (P=0.04, P=0.01).

CONCLUSIONS

Overall, the application of TI did not have immediate effects on dynamic balance performance or ankle muscle activity in either CAI or non-CAI soccer players. Nonetheless, CAI players seemed to employ a different ankle strategy involving the MG muscle, possibly to control stability during dynamic movement, particularly in the posteromedial and posterolateral directions.

The suppression of lower leg electromyography when walking in textured foot orthoses

Previous research exploring the effects of tactile feedback in standing balance protocols may have generated results that misrepresent the modulatory capabilities of cutaneous afference on generating motor output responses. The neurosensory mechanism of textured foot orthoses to maximize the activation of cutaneous mechanoreceptors is through repetitive foot sole skin indentation. Thus, the purpose of this experimental protocol was to investigate muscular activity amplitude changes during the stance phase of gait, specifically when walking on level ground and when stepping onto a raised wedge, and while wearing textured foot orthoses compared to orthoses without texture. Twenty-one healthy young adults were fit to a standardized neutral running shoe and completed five level and wedged walking trials wearing both orthoses. Kinematic, kinetic and electromyography (EMG) data were recorded from eight lower limb muscles. The results of this study revealed EMG suppression of lower leg musculature during stance when walking in textured foot orthoses, and this was most pronounced when lower leg musculature is typically most active. The addition of texture in foot orthoses design, spanning the entire length of the foot sole, appears to be a clear mechanism to modulate neurosensory feedback with intent to suppress EMG of shank musculature during gait.

Effect of foot orthoses on balance among individuals with flatfoot: A systematic review and meta-analysis

Individuals with flatfoot have impaired proprioception owing to ligament laxity and impaired tendons, which can result in poor balance. Foot orthoses (FOs) have been reported to stimulate plantar mechanical receptors and are used to manage foot overpronation in individuals with flatfoot. However, the results of the use of FOs to improve balance are inconsistent. In this systematic review and meta-analysis, we aimed to identify and investigate the effects of FOs on balance in individuals with flatfoot. Electronic databases were searched for articles published before March 2023. Peer-reviewed journal studies that included adult participants with flexible flatfoot and reported the effects of FOs on balance were included and classified based on the study design: randomized control trials (RCT) and non-RCTs. Four RCT studies were retained, and their methodological quality was assessed (mean, 63.2%; range 47.3%-73.1%: high), as were three non-RCT studies (mean, 54.1%; range, 42.1%-68.4%: high). Meta-analysis was performed by calculating the effect size using the standardized mean differences between the control and FO conditions. Transverse-arch insoles immediately improved static balance after use. However, no immediate significant effect was found for medial archsupport FOs, cuboid-posting FOs, or University of California Berkeley Laboratory FOs during the study period (2-5 weeks) when compared with the controls. The transverse-arch insole is the most effective FO feature for improving static balance. However, the high heterogeneity between study protocols contributes to the lack of evidence for the effects of FO on balance in people with flatfoot.