نشریه پژوهش در طب ورزشی و فناوری
پیاپی 6 (پاییز و زمستان 1392)

The aim of this study was designing a specific upper body anaerobic power test for wrestlers and determining validity, reliability and objectivity of the designed test. In order to assess the anaerobic power of wrestlers on the basis of upper body Wingate test, Twenty two wrestlers (age=23/40±3/20 year, height=173/13±6/97 cm, weight=74/55±3/88 kg) of Tehran wrestling team (most of them were Asian champion) were participated in this study. Mean, maximum and minimum of anaerobic power and fatigue indices assessed by both tests. In order to analysis the correlation between power indices and physiological indices (blood lactate and heart rate), Pearson correlation has been used, and the differences between blood lactate after 2 min in both tests assessed. The result indicated that there was significant correlation between maximum (p=0/001 r=0/739), mean (p=0/001 r=0/670) and minimum (p=0/01 r=0/650) of power and fatigue indices (p=0/003 r=0/610) obtained by designed test and Wingate test. The result showed that there was significant correlation between heart rate immediately after doing both tests (p=0/001, r=0/705) and also the result show that there was not significant correlation between blood lactate after 2 min. of doing both tests (p=0/07 r=0/353). Statistical analyses also showed no difference between the blood lactate after 2 min of doing both tests. Analyzing the validity of designed test, revealed that there was significant correlation between max (p=0/000 r=0/840), mean (p=0/000 r=0/861) and minimum (p=0/000 r=0/830) power and fatigue indices (p=0/000 r=772) after performing twice of designed test. In analysis objectively of the designed test, the result revealed that there was significant correlation between max (p=0/000 r=0/832), mean (p=0/000 r=0/858) and minimum (p=0/000 r=0/805) power and fatigue indices (p=0/000 r=0/832) which was done by two different tester. It can be concluded that in respect to Wingate upper body test, the designed test in this study is valid and reliable test to measure the anaerobic power of wrestlers.

Introduction and The rate of overweight and obesity of childhood is dramatically increasing. It seems that mechanical load would affects motor activities for instance walking pattern. This study undertaken to compare spatiotemporal parameters of walking among overweight and normal childrens 10 to 12 years. In this semi-experimental study, 30 subjects (15 overweight boys and 15 normal boys) are randomly selected participated. Footprints recorded during walking with ink and paper system. In order to make comparison of spatio- temporal parameters of walking of subjects Independent Samples t-Test is used. Significant difference was seen in three parameters spending time, speed and cadence between the two groups; in addition, there is significant difference in foot progressive angle between dominant and non dominant limbs.Discussion and According to the findings of this study, which confirms findings of previous studies, in order to optimize walking pattern perhaps overweight changes the pattern of gait through improvement of motor control.

The purpose of this study was to compare of hip abductor and external rotator muscles strength between male soccer players with ACl rupture and healthy male soccer players. 30 male participants (15 soccer players with ACL rupture as sample group and 15 healthy soccer players as control group) participated in this study. Hip abductor and external rotator muscles strength tests including normalized isometric strength of hip abductor and hip external rotator muscles were evaluated by dynamometer in both groups. Independent t-test was used to compare datas between two groups.The results showed significant differences in normalized isometric strength of hip abductor muscles (P=0.003) and hip external rotator muscles (P=0.127). Regarding the findings of this study, there is significant difference of hip muscles strength between male soccer players with ACL rupture and healthy male soccer players.

Balance and strength are important abilities that athletes should have them. This study was designed to investigate the relationship between maximum leg press (non-weight bearing closed kinetic chain) and squat (weight bearing closed kinetic chain) strength with statistic and dynamic balance. Thirty (15 men and 15 women) physically active participants (age, 22.13 ± 1.54 years; height, 171.26 ± 6.92 cm; weight, 66.02 ± 8.27 kg) completed the study. The Biodex Balance System was used to evaluate balance performance. Subjects completed two, 40 seconds trials attempting to maintain their statistic and dynamic balance and Overall Stability Index, Anterior/Posterior Index and Medial/Lateral Index were obtained. Maximum strength also was measured with a 1RM squat and leg press. Significant correlations were found between the measurements of 1RM squat with static anterior-posterior indices (r, 0.019; P=- 0.541) and dynamic medial-lateral indices (r, 0.021, P=-0.532) in men and with static anterior-posterior indices (r, 0.016, P=-0.552) and dynamic anteriorposterior indices (r, 0.032; P=-0.491) in women. No significant correlations were found between the measures of 1RM leg press and balance indices in both groups. The results of this study indicate that maximum squat strength has more relation with some indices of static and dynamic balance than maximum leg press.

The purpose of this study was to examine the difference between two types of the soccer instep kick in temporal sequence of motion and muscle electromyography, during forward swing phase of the kick. Ten elite soccer players, volunteered as subjects in the study. To culculate the kinematics data, we used DLT method with two video camera that filmed five markers fixed on anatomical points of lower body, at 240 fpm. Moreover the electromyography of rectus femoris, vastus medialis and tibialis anterior were estimated. Kinematic data from ten players was extracted using image processing toolbox of MATLAB software. Using these results, we compared sequences of joint motion and progression of activation muscle in low drive and high drive kick. The results indicate that there was a difference in ranks of muscle activation between two kick, but there were no difference in muscles activation time and sequence of joint motion between low drive and high drive kick. Furthermore both kicks have a similar proximal-distal pattern and interaction in muscles contraction and joints motion.

The purpose of this study was to investigate the number of trials necessary to obtain optimal biomechanical responses of lower extremity joints during 10 consecutive soccer instep kicks. The kicking motions of dominant legs were captured from 15 professional adult male soccer players using six synchronized high-speed infra-red cameras at 200 Hz. Some of the important biomechanical parameters are maximum hip and knee angular velocity, maximum of hip and knee moment, at forward and impact phases and finally maximum ball velocity after impact selected to be analysed. There was a significant decrease of ball velocity between the first and the fifth kick and the subsequent kicks. Similarly, the knee angular velocity showed a significant decrease after the fifth kick and thereafter. Comparing to the first kick the hip angular velocity has been shown to decrease after the sixth kick and thereafter and the hip moment result of the sixth kick was significantly lower when compared to the first kick. Moreover, the knee moment result of the fourth kick was significantly lower in comparison with the first kick. In conclusion, it seems that five consecutive kicks are adequate to achieve high biomechanical responses and selecting more than five kicks will be unusual.

The purpose of this study was to survey effects of twelve weeks endurance training on serum levels of selected hormones in underweight men. Eighteen healthy underweight men were randomly divided at two groups: endurance training and control. Serum levels of adiponectin, testosterone, and cortisol were assessed before and after training. Endurance training protocol consisted of twelve weeks pedaling on cycle ergometer (3 sessions per week, intensity 60-70% of reserved heart rate, duration of each session 20-40 min). Data were analyzed by SPSS16 software and using Independent and Paired t-tests. Statistical significance was accepted at P<0.05. Endurance training has no significant effect on serum concentrations of adiponectin (14.4±2.4 vs. 13.9±1.8 μg/ml) and cortisol (178.2±48.7 vs. 167.3±39.6 ng/ml) (p>0.05), while decreased serum testosterone concentration (8.2±1.6 vs. 7.2±1.8 ng/ml) (p=0.032) and increased VO2max index (p=0.008). Performing endurance training twelve weeks has no effect on serum adiponectin concentration in underweight men, likely due to lack of change in body fat percent. It doesn’t appear that decrease of circulating levels of testosterone following this period training has detrimental effects on anabolic-androgenic testosterone-dependent processes, and even according to previous studies, it can be useful for cardiovascular health. Anyway, cardio respiratory fitness level of underweight men improved following the endurance training. It doesn’t appear that endurance training has effect on resting (non-exercise condition) levels of cortisol concentration in underweight men.

24-67% of recreational runners suffer from running-related injuries. The purpose of this study was to test the effect of unstable shoes on selected ground reaction force (GRF) parameters during stance phase of running. 20 healthy men (age of 21±2.27 years, height of 176.93±5.39 cm, and mass of 72.30±8.84 kg) ran on the force plate placed in the middle of 15 m runway in barefoot, with unstable and control shoe conditions. Peak vertical GRF, posterior force, loading rate and impulsive passive force variables were calculated in the three conditions. A repeated measure of ANOVA and Duncan post-hoc tests applied to test the hypothesis (p<0.05). vertical loading rate and vertical peak passive force variables were significantly increased in unstable shoe condition compared to control shoes. In addition, peak posterior force and impulsive passive force variables were significantly increased in unstable shoe compared to control shoe. unstable shoe could increase ground reaction force parameters on foot during running. This finding suggests that unstable shoes could possibly increase risk of running related to injuries.