Journal of Advanced Sport Technology
Volume:1 Issue: 1, Winter-Spring 2017

There is no doubt that sporting surfaces are extremely important for every activity. However, there is not sufficient scientific report regarding the effect of the area elastic surface floor with common range stiffness on vertical hopping safety and performance. The aim of this study was to examine the effect of custom area elastic surface with different stiffness on the hopping performance and safety with emphasis on familiarity to the surfaces. Fifteen young and healthy experienced male were volunteered in this study. Kinematic and kinetic data recorded during hopping on four surfaces (300-500 kN/m) using the Motion Analysis System and AMTI force plate. In the data analysis process, leg and joint stiffness, maximum vertical ground reaction force, mechanical energy and power and angular position of joints calculated. The results of this study show that surface stiffness does not effect on the leg and joint stiffness, but after familiarity to the surface, there was a significant increase in 400 kN/m surface positive mechanical energy and power of ankle joint and a significant decrease in negative mechanical energy and power of knee joint (P<0.05). In conclusion, it seems the change in surface stiffness after familiarity to the surface causes an improvement of hopping performance without any change in leg and joint spring stiffness. It can be proposed that deformation following impact also does not enough to significantly reduce the vertical ground reaction force.

In our technological world, there are plenty of opportunities to utilize science and engineering to improve exercise performances. Muscular strength is one of the main components of the physical fitness. In this regard, the Isometric Dynamometer is a scientific instrument intended to quantify the muscle strength. Hence, the aim of this project was to manufacture an innovative computerized isometric dynamometer package and relevant software. In the current project a high precision isometric force transducers (2000 and 5000 N), instrumental amplifier, high precision Analog-to-Digital Converter connected to a high speed microcontroller were implemented. A graphic LCD, MicroSD memory card used in the data logger to display and record the force data. Professional software was designed to communicate with the data logger by a USB port and display four-channel line charts in online mode. Offline data processing and record the processed data on a database is also available. This device provided an innovative method of simultaneous right & left side dynamometry using two sensors to measure any imbalance in the strength between two limbs. Additionally, this package has a grip dynamometer, a pull and press hands dynamometer, and optional connection to other force sensors. The linearity of the sensors’ output for 0, 10, 50, 100, 200 kg weights was 99.99 and test-retest measurements confirmed very high reliability (0.99±0.012). This package was extensively applied in the laboratory researches due to its unique simultaneous force measurement feature. Hence, this package with distinctive specifications can extensively implement in clinic, gym, laboratory, field tests.

In different sport activities, taping is widely used as a treatment in the prevention and treatment of lower or upper extremity disorders. The aim of this study was to determine the immediate effect of Kinesio Taping (KT) on the ground reaction force (GRF) components during bilateral drop landing task in athletes with concurrent pronated foot and patella-femoral pain syndrome (PFPS). Twelve male athletes (mean age = 20.1 ± 1.4 years; mean height = 169.4 ± 4.8 cm; mean weight = 66.9 ±10.4 kg) with concurrent PFPS and pronated foot were volunteered to participate in this study. Subjects were instructed to perform three bilateral drop landing attempts, before and after Kinesio Taping. To perform the bilateral drop landing tests, the subjects were instructed to execute a double-leg landing task by stepping off a platform (height=30 cm) and landing barefoot with both feet on a Kistler force platform at a frequency of 1000 Hz. Meanwhile, they were asked to employ their natural landing style. Paired sample t test was chosen to measure differences between both with and without taping conditions. The statistical significant level was set at P <0.05.

Peak vertical GRF amplitude (Fzmax) was similar between both conditions (P>0.05). However, taping condition displayed a lower peak posterior GRF amplitude (by 44%) than that without taping condition (P=0.002). Furthermore, peak medio-lateral GRF amplitudes (Fymax and Fymin) did not show any significant diferences between both conditions (P>0.05). KT could decrease the possibility of injury by improving both amplitude and time to peak of GRF during bilateral drop landing task in athletes with concurrent pronated foot type and PFPS.

In this study, an investigation was done in order to increase stability of ankle and reduce injuries resulting twist while using aid orthosis and effort in providing superior samples. Therefore this study aims to investigate the effect of ankle hinged Stirrup brace on the Sagittal position of ankle joint in healthy individuals. Eighteen healthy subjects participated in this quasi-experimental study (8 males, 10 females) aged 19 to 30 years. Individuals were selected by non-random sampling and accessible sampling type based on inclusion criteria. Dorsiflexion angle at the moment of heel contact with the ground while walking in the 3 different steps of test with just shoes, shoes with articulated Stirrup brace, shoes with modified articulated Stirrup brace (stretch strep) was recorded by using (VICON Motion Systems) motion analysis system. For comparison of the supposed positions also paired t test was used. Articulated ankle brace have no significant effect on the ankle joint sagittal plane position. In addition, the modified brace cause a significant change in the position of the ankle joint sagittal plane and increase the angle of the ankle joint in the desire direction. Adding a stretch strap to the main plantar brace according to the picture presented in the research methodology as an involuntary factor creates movement restrictions in the sagittal plane to increase dorsiflexion angle that the change would lead to increased dorsiflexion ankle angle in order to increase consistency at the moment of heel contact with the ground in healthy individuals.

In this study, the kinematic effect of two molding methods in the manufacture of foot orthoses on ankle joint was examined. The aim of this study was to determine a more beneficial method about ankle kinematics in the manufacture of insoles for people with flexible flat foot. Ten males aged 19 to 27 years, with normal BMI and normal gait pattern participated in this study, all of them had flexible flatfoot. Each person wearing special shoes on three situations: stepped without the insole, with the Slipper cast insole and Circumferential wrap method insole and in each situation completed a walk cycle. The kinematic data were collected and measured for each subject under three assumed positions by VICON motion analysis system. For comparison and analysis of three assumed situation, repeated measures test (ANOVA) was used. The results of this study show that the use of two molding method, had no immediate effect on reducing the average maximum eversion angle of the ankle. Eversion speed limit in the ankle was not affected by insole molding and no significant difference was observed. Compared to the situation without insoles, insole with the Slipper cast and Circumferential wrap molding method led to little difference in amplitude eversion. This study evaluated immediate effect of insoles. Two custom foot orthotics intervention did not lead to significant decreases in maximum eversion angle of ankle in the frontal plane.

Ankle injury research is typically performed with cadavers or by the clinical measuring technique which both of them have several problems such as general degradation of tissues. Numerical methods help us to overcome these problems. Therefore, the goal of this study was to compute the stress in Anterior Talofibular (ATF) ligament under different strategies of landing using finite element modeling for males and females. These strategies included the variation of the ankle flexion angle and hindfoot angle at the instant of initial contact with the ground.For calculating stress in ATF ligament, ankle torques were inputted to finite element model. Ankle torques were obtained from a five-link dynamic model using inverse dynamic approach. Input data for dynamic model included motion kinematics during drop landing from 60 cm height during 0.198 seconds after initial contact of the foot with the ground. Finite element model was created by manipulating of CT and MR images using the appropriate software. Results showed that stress in ATF ligament increase when torques in the ankle joint increase. Results from finite element model showed that when initial ankle with the ground was 68.7 degrees peak ATF ligament stress for females was lower than when initial ankle with the ground was 88.7 degrees. Additionally, increased initial plantar flexion of ankle leads to increasing stress up to 5.27 times in ATF ligament. Comparing this model and previous investigations’ results showed that this method is a useful tool to simulate landing condition for any person and to help us to predict whether those conditions probably lead to injuries or not.