Effects of Stabilization-based Pilates Exercise on Gait and Balance in Women With Flexible Pesplanus

Study object This randomized controlled trial aims to assess the effects of stabilization-based Pilates exercises on gait and balance in women with flexible flatfoot. The study focuses on determining whether a specific Pilates program can provide non-invasive rehabilitation for improving gait patterns and reducing balance instability.

Participants The study will include 22 healthy women with flexible flatfoot who have no congenital deformities or diseases of the feet, knees and have a navicular drop of ≥10 mm. The participants will be recruited from "Clinical Pilates" studio in Busan city. Women with bilateral flatfoot (n=22) will be randomly allocated to either the Pilates training group (PTG, n=11) or the non-training group (NTG, n=11).

Outcome measure gait assessment and data acquisition: Participants undergo several practice walks to familiarize themselves with the gait assessment. Three records are averaged once they show a normal gait pattern. The assessment uses measurements from both legs and is conducted in a non-distracting environment.

Seven 3D infrared motion capture cameras (Vicon camera MX-T20, Oxford Metrics, Oxford, UK) and 16 circular reflective markers (14-mm diameter) are used to acquire the data for the gait assessment. The reflective markers are attached to the anterior superior iliac spine, posterior superior iliac spine, lateral mid-thigh, lateral femoral epicondyle, mid-shin, lateral malleolus, second metatarsus, and heel of both the left and right legs. The height, body weight, and width of knee and ankle joints are measured and entered. Gait analysis includes temporal parameters, such as foot-off, step time, stride time, walking speed, and cadence. Kinematic data are collected using Vicon plug-in gait system (Oxford Metrics) at a sampling frequency of 100 Hz.

balance assessment and data acquisition: The participants are instructed to stand with their arms crossed in front of their chest, with one leg supported and one leg raised with the knee at a 90° angle. Participants hold that standing position for 40 seconds. Three successful attempts are recorded for each participant. Measurements are taken for both legs, and the participants are given sufficient time to rest between each stage of the experiment.

For Center of Pressure (COP) measurement, data from 40 seconds of single leg support on a force platform (AMTI-OR6, Watertown, MA, USA) are utilized. The data are calculated and assessed as time series data. COP sway variability is assessed based on the Root Mean Sqaure (RMS) in Anterior-Posterior (AP) and Medial-Lateral (ML) directions, while AP and ML components of COP velocity and range are also assessed. Kinematic data are collected using the Vicon Plug-in Gait system at a sampling frequency of 100 Hz.

Exercise intervention:

The exercise intervention consists of two sessions each week, for a total of 16 sessions over an 8-week period. Each training session is structured into eight sets, totaling 50 minites. This includes a 5-min warm-up period, followed by 40-min of the main exercise component, and concluding with a 5-min cool-down phase. The Pilates training is supervised by an instructor with 15 years of experience and a professional Pilates certification.

Statistical analysis IBM SPSS Statistics for Windows (version 28.0; IBM Corp., Armonk, N.Y., USA) is used to conduct descriptive statistical analyses, including means and standard deviations. Statistical significance is set at p<0.05.

Differences in mean values between the groups for each temporal parameter will be assessed using independent samples t-tests. Additionally, due to the small sample size, non-parametric tests (Mann-Whitney U test) will be conducted. Furthermore, paired samples t-tests will be used for within-group pre-test and post-test comparisons.

Inclusion criteria

• Bilateral navicular drop of ≥10 mm

Exclusion criteria

• Clinical diagnosis of Alzheimer's Disease
• Severe heart conditions (heart failure, myocardial infarction)
• History of knee, ankle or hip injuries within the last 3 months
• Chronic lung disease
• Pregnancy
• Congenital Foot Deformity ( Polydactyly, Syndactyly)