# Iliotibial Band Behavior Assessed Through Tensor Fasciae Latae Electromyographic Activity with Different Foot Orthoses in Recreational Runners According to Foot Type: A Cross-Sectional Study

## TL;DR

This study examines how different foot types and orthoses affect TFL muscle activity in runners, suggesting that pronating insoles may help reduce TFL activation and potentially prevent ITBS.

## Contribution

The study introduces a novel approach to understanding ITBS by analyzing TFL EMG activity in relation to foot type and orthotic use.

## Key findings

- Supinators showed higher TFL activation compared to neutral foot types during baseline conditions.
- Pronating insoles significantly reduced TFL activity in both neutral and supinated foot types.
- The study recommends assessing foot type and using pronating insoles as a complementary treatment for ITBS.

## Abstract

Background: Iliotibial band syndrome (ITBS) through the tensor fascia latae (TFL) is a well-known pathology among runners whose etiology is not completely clear, nor is the effectiveness of plantar insoles for different types of feet known well enough for them to be considered a possible approach for this issue. Objective: to understand how foot type and foot orthotics may influence the electromyographic (EMG) activity of the TFL. Methods: A total of 41 healthy recreational runners (mean age 32.66 ± 3.51) were recruited for the present cross-sectional study, categorizing them as neutral (NEUg = 15), supinators (SUPg = 15), and pronators (PROg = 11) according to the foot postural index, over a period of 11 months. The EMG of the TFL was measured using a surface electromyograph device while they ran on a treadmill at a constant speed of 9 km/h for 3 min, randomly using supinating (SUP), pronating (PRO), or heel lift (TAL) insoles of 5 mm each one, compared to the baseline condition (SIN). The intraclass correlation coefficient (ICC) was performed to check the reproducibility of the tests, pairwise comparisons with Bonferroni adjustment were made, and to test the differences between measurements, the Friedman test was performed. Results: The Shapiro–Wilk test indicated a normal distribution of the sample (p > 0.05). Almost all obtained results showed a “perfect reproducibility” close to one; a significant statistical increase was observed in the mean EMG values from NEUg (87.58 ± 4.81 mV) to SUPg (97.17 ± 4.3 mV) (p < 0.05) during SIN+ basal condition. Additionally, there was a statistical reduction from SIN (87.58 ± 4.81 mV) vs. PRO (74.69 ± 3.77 mV) (p < 0.001) in NEUg and from SIN (97.17 ± 4.3 mV) vs. PRO (90.96 ± 4 mV) (p < 0.001) in SUPg. Conclusions: The SUPg exhibited increased activation of TFL fibers compared to the NEUg, likely due to the biomechanical demands associated with a supinated foot type. In contrast, the use of PRO appeared to promote relaxation of the TFL fibers by inducing internal rotation of the lower limb. Based on these preliminary results from a cross-sectional study in a healthy population, it is recommended to assess foot type when addressing ITBS and to consider the use of PRO as a complementary therapeutic strategy alongside conventional treatments.