مجله بیومکانیک ورزشی
سال دوم شماره 1 (بهار 1395)

The main aim of the study was comparing the main anthropometric and biomechanics indexes in elite male adult Wushu athletes in both Taolu and Sanda disciplines.
The sample of the present study included 20 elite male Wushu athletes who were checked for 33 anthropometric and 11 biomechanical indexes. The normality of the data was checked by Kolmogorov–Smirnov normality measure. Factor Analysis was run to determine the main indexes and independent samples .T-test was used at a significance level of p The results showed that in Taolu group, sitting height, waist to pelvic circumference ratio and body fat percentage were higher. Also, the weight, arm length, leg length, head circumference, arm circumference in contraction, shoulder width, the width of the wrist and body mass index were greater in the Sanda group. There was a meaningful difference between endurance indices, lower limb muscular strength, semi dynamic balance in posterior-lateral direction, semi dynamic balance in right-anterior direction, semi dynamic balance in posterior-medial direction, semi dynamic balance in posterior-lateral direction (p There is a significant difference in the main anthropometric and biomechanical indicators of Wushu in both Taolu and Sanda disciplines. It appears that balance, endurance – strength of foot in the biomechanical properties are the most important Indicators in Taolu.

The aim of this study was to evaluate relationship between foot posture and static and dynamic balance in athlete and non-athlete girls.
Material and there were 40 girl student that 20 of them were athlete aged 21/5+ 4/62 and 20non-athlete aged 22/8 +2/61. to evaluate foot posture, dynamic balance and static balance used radmond,s six scale visual method, star exersion balance test, and BESS test respectively. To analyzing data, indipendent t-test and pearson correlation test was used.(p≤0/05)
there was not significant correlation between foot posture with dynamic and static balance in any of athlete and non-athlete girls group (p≥0/05) but there were significant difference in foot posture, dynamic and static balance between two group (p≤0/05).
this research show that athletes have a propriate foot posture index and balance function. also we can probably say that fitness and neuro-muscular performance affect on balance more than biomechanic factors such as foot posture. To evaluate this hypothesis we need more researchs.

The aim of this study was to evaluate the impact of the external focus of attention on the rotator cuff muscle activity for the timely hit forehand drive by table tennis players.
Twelve professional table tennis players with mean age of 26.5 years voluntarily participated in this study. The electrical activities of the muscles of the shoulder girdle using M.A 300 machine and bipolar electrodes surface under two conditions .First with external focus of attention and then without such attention were recorded, first without any guidance blows forehand drive was carried out by subjects (without focus). Then such subject was asked to focus their attention on the area marked for the ball landing (external focus of attention).
Muscle activities in both preparation and tapping phases were analyzed the three –dimensional (200 Hz, Vicon, with four camera series T) motion analysis system was used to obtain the data. Data was analyzed by running reported measures ANOVA at a significance level of p In without external attention situation, muscle activity did not change significantly compared with the external focus of attention situation (p>0.05) but the different between the intensity of muscle activity was meaningful. This suggests that there is a mutual influence between the two attention factors and muscles (p=0.03), that is, orientation can have a significant effect on the severity of muscle contraction. Intensities of muscle contraction in the preparation and tapping were different (p On the forehand drive technique, the anterior deltoid muscle has the most activity. The type of focus and attention had a significant impact on the change of activity of muscles relative to each other, and the greatest impact is on the reduction of activity of the infraspinatus muscle. This type of focus delays fatigue and results in an increase in the efficiency of neuromuscular in the activities of skills.

Increased vertical ground reaction force loading rates and lack of comfort footwear in the early stance phase can increase the risk of overuse injuries. The purpose of this study was to investigate the effect of Five-finger shoes on vertical ground reaction force loading rate and perceived comfort during the stance phase of running.
15 male students (aged 24 ± 5/24 years, weight 75/8 ± 4/61 kg, height 178/6 ± 6/64 cm) were selected. Subjects were asked to run over a force plate, in control shoe, five finger shoe and barefoot conditions. Loading rate using the slope of the vertical reaction force and perceived comfort were determined using a visual analogue scale. One factor repeated measures ANOVA was used to test the loading rate hypothesis and Paired t-tests was used to test the meaningfulness of perceived comfort (P The effect of shoes on loading rate was found to be not significant (P=0.1). However, comfort of control shoes increased by 10. 92% as compared to that of five-finger shoes (P=0.001).
The loading rate of five-finger shoes is the same as that of barefoot during running; however, as subjects did not perceive them as comfortable as regular shoes are five-finger shoes cannot be advised as a desirable choice in exercises.

The aim of this study was to investigate the relationship between isokinetic relative torques of hip, knee and ankle joints and the height of guide leg jump in young men.
27 college male athletes with mean age of 25±3.5 years, height 178.5±7.8 cm and weight of 75.7±10.7 kg voluntarily participated in this study. Isokinetic torque of hip, knee and ankle joints and the height of vertical jump were measured using BIODEX SYSTEM PRO 4 and digital vertical jumping tester systems respectively. Pearson correlation test at p Results showed that there were significant correlations between height of jump and hip joint flexion (p= 0.047 & r= 0.39) and extension (p= 0.003 & r= 0.55) torques of guide leg, hip joint extension torque of support leg (p= 0.020 & r=0.45) and knee joint flexion (p= 0.019 & r=0.45) and extension torques of support leg (p=0.006 & r=0.52).
The results of this study show that flexion and extension torques of hip joint in guide leg and knee joint in support leg and also extension torque of hip joint in support leg have main effect on height of guide leg jump. Thus, in designing a specific training program for athletes in whom the nature of jump in their sports is guide leg jump, particular attention should be given to hip and knee joints strength.

The aims of this study were to identify the most appropriate indicator to assess the balance in the sudden perturbation test conditions.
In this study, 13 freestyle national wrestlers at the age of 20.5±2.4 and 13 normal subjects with average age of 23.5±1.4 were used recruited. Balancing test was carried out under two conditions: standing with the guard (guard) and stand feet shoulder width apart (standing). To measure the balance parameters, the RS-scan system was used, and for external perturbation movable plant with weights equal to 12% of the mass was used. The independent t-test for statistical analysis in each direction between the two groups was used.
Center of pressure (CoP) travel distance in the anterior, posterior and external directions, wrestlers were more than those in normal individuals in both positions; for guard position (p = 0.01, p = 0.01, p = 0.5) and (p = 0.2, p = 0.5, p = 0.01) in stand position. The COP average speeds in the anterior, posterior and external directions in both conditions were more in wrestlers than that normal group, (p = 0.01, p = 0.08, p = 0.01) in the guard position and (p = 0.27, p = 0.1, p = 0.01) in the stand position. The wrestlers were able to get stable as soon as possible in both positions and in four direction (p=0.001).
Athletes in sudden perturbation want to reach equilibrium and stability in shorter time by increasing speed CoP. Thus it seems, time to stability can be a good indicator for balance evaluating.