Wan Mohd Radzi Rusli

Leg Length Discrepancy: Dynamic Balance Response during Gait

Balance in the human bodys movement is generally associated with different synergistic pathologies. The trunk is supported by ones leg most of the time when walking. A person with poor balance may face limitation when performing their physical activities on a daily basis, and they may be more prone to having risk of fall. The ground reaction forces (GRFs), centre of pressure (COP), and centre of mass (COM) in quite standing posture were often measured for the evaluation of balance. Currently, there is still no experimental evidence or study on leg length discrepancy (LLD) during walking. Analysis of the stability parameters is more representative of the functional activity undergone by the person who has a LLD. Therefore, this study hopes to shed new light on the effects of LLD on the dynamic stability associated with VGRF, COP, and COM during walking. Eighteen healthy subjects were selected among the university population with normal BMIs. Each subject was asked to walk with 1.0 to 2.0 ms−1 of walking speed for three to five trials each. Insoles of 0.5 cm thickness were added, and the thickness of the insoles was subsequently raised until 4 cm and placed under the right foot as we simulated LLD. The captured data obtained from a force plate and motion analysis present Peak VGRF (single-leg stance) and WD (double-leg stance) that showed more forces exerted on the short leg rather than long leg. Obviously, changes occurred on the displacement of COM trajectories in the ML and vertical directions as LLD increased at the whole gait cycle. Displacement of COP trajectories demonstrated that more distribution was on the short leg rather than on the long leg. The root mean square (RMS) of COP-COM distance showed, obviously, changes only in ML direction with the value at 3 cm and 3.5 cm. The cutoff value via receiver operating characteristic (ROC) indicates the significant differences starting at the level 2.5 cm up to 4 cm in long and short legs for both AP and ML directions. The present study performed included all the proposed parameters on the effect of dynamic stability on LLD during walking and thus helps to determine and evaluate the balance pattern.

Finite element modelling of Plantar Fascia response during running on different surface types

Plantar fascia is a ligament found in human foot structure located beneath the skin of human foot that functioning to stabilize longitudinal arch of human foot during standing and normal gait. To perform direct experiment on plantar fascia seems very difficult since the structure located underneath the soft tissue. The aim of this study is to develop a finite element (FE) model of foot with plantar fascia and investigate the effect of the surface hardness on biomechanical response of plantar fascia during running. The plantar fascia model was developed using Solidworks 2015 according to the bone structure of foot model that was obtained from Turbosquid database. Boundary conditions were set out based on the data obtained from experiment of ground reaction force response during running on different surface hardness. The finite element analysis was performed using Ansys 14. The results found that the peak of stress and strain distribution were occur on the insertion of plantar fascia to bone especially on calcaneal area. Plantar fascia became stiffer with increment of Youngs modulus value and was able to resist more loads. Strain of plantar fascia was decreased when Youngs modulus increased with the same amount of loading.

Effect of leg length inequality on body weight distribution during walking with load: A pilot study

This paper presents a pilot study on the effect of leg length inequality (LLI) on the body weight distribution. Plywood block was used to mimic the artificial LLI. The height of the plywood was increased up to 4.0 cm with 0.5 cm increment. Hence, eight different height of LLI was considered in order to investigate which height of LLI initiated the significant effect. The experiment was conducted on a healthy subject that walking on the force plate in two conditions; with a load of 2 kg (carried by a backpack worn by the subject) and without load. Qualisys Track Manager (QTM) system was employed for data processing. The results showed that the short leg subjected to more weight compared to the long leg during walking with inequality of leg length especially when carrying additional load.

Clinical effects of leg length discrepancy through ground and joint reaction force responses: A review

Leg length discrepancy (LLD) is caused either due to functional disorder or shortening of bone structure. This disorder could contribute to the significant effects on body weight distribution and lumbar scoliosis at the certain extend. Ground reaction force and joint reaction force are the parameters that can be used to analyze the responses in weight distribution and kinetics changes on the body joints, respectively. Hence, the purpose of this paper is to review the studies that focus on the clinical effects of LLD to the lower limb and spine through ground and joint reaction force responses that could lead to the orthopedics disorder.

Kinematics of Foot during Running: A Review

Running can be considered as an important movement since it can be categorized as one of daily activities. However, running movement may contribute to injuries for example, subject to plantar fasciitis. The objective of this review is to summarize the information of published articles related to kinematics aspect, which is one of key factors that can cause injury in running movement. The search strategy was carried out from Science Direct database. The variability of methodological protocol due to different running mode and condition influenced the foot kinematics which has been proved by the findings from the experiments. In future, research on investigating the suitable speed and condition to standardized running methodological protocol should be done in order to obtain a reliable result.

Adjustable Crank: A Comparison Between Wireless Motion Sensor and Motion Capture Analysis Camera for Crank Kinematic Measurement

This paper is focused on the development of wireless measured kinematics specifically for cycling. The aims of this study are to create sensory system with portability, reliability and based on the wireless system. The adjustable crank is novel type of prototype crank that design to maximize the minimum torque at bottom dead center (BDC) and top dead center (TDC) where the crank can be set for ±10° maximum with addition of 5° back and forth from inertial 0° TDC point. The system will measure the power output during cycling to evaluate the cyclist performance. In order to measure power output, the angle displacement (kinematic) and force measurement (kinetic) are needed. The inertial measurement unit (IMU) combination of accelerometers and gyrometers was used to measure the angle and angular velocity of the crank. The system has been validated using a visual system to compare the output provided by IMU. The RMS error value between motion capture camera and IMU for crank angle was 0.480 ± 0.325°. The RMS error value for normalized angular velocity was 0.743 ± 0.911 %. The wireless-based system will aid to reduce the wiring complexity and user-friendly portable measuring system. The wireless communication using Zigbee protocol with two Xbee devices point-to-point will be used to transfer the information to the computer controlled system. The enhancement of this system can be used for coaches for cycling monitoring system to improve cyclist coordination, strategy, and technique.