Research in Sport Medicine and Technology

One of the factors affecting jump-landing patterns is fatigue. Fatigue is an inevitable component of physical
activity, hence the aim of the present study was to investigate the effect of functional fatigue on landing
mechanics through Landing Error Scoring System (LESS).Fourteen male college students with a mean age of
22±2 years, weight of 68.3±7.2 kg and height of 174±4 were randomly divided into two groups: experimental and
control. Effect of independent variable, fatigue, due to activities resembling athletic training or competition (6-
stations functional fatigue protocol) on dependent variable, landing mechanics, through pre test-post test was
investigated. The independent t-tests and non-parametric U-Mann Whitney test was used for statistical analysis
of data (P < 0.05). The results of the present study indicated the relationship between fatigue and attenuation of
landing mechanics (P=0.02), and therefore an increase in injury risk. Also it was shown that the effect of fatigue
on decreasing knee flexion angle at initial contact was significant (P=0.022). With regard to the results, it can be
concluded that functional fatigue induced by physical activities can alter landing mechanics, and increase loading
of lower extremity joints, particularly the knee. So the risk of injury in these joints may be increased.

The aim of this study was to Compare the effect of resistance training with active and passive rest on aerobic
and anaerobic fitness in soccer players. For this purpose 16 players of Foolad Mobarakeh Sepahan club,
accidentally were divided into rest and active group (Height 177.78±6.68 cm, Weight 64.88±7.97 kg, age
18.22±0.83 years ,and percent fat 20.47±1.8) and rest passive group(Height 178.57±6.99 cm, Weight 64±
6.6kg, age 18±0.81 years ,and percent fat 20.05±1.7). The tests were performed in this order: maximal oxygen
consumption, maximal strength, Tmax, muscular endurance, Hoff and RAST test in the pre and post test. The
exercises were done for 8 weeks and twice week with 10 exercises of 30 to 50 percent of maximal strength
with this difference that the active rest group performed 3 sets of 20 repetitions exercise in 30 seconds that rest
interval between 30 seconds was completed with 2 sets of 10 repetitions exercise in 30 second. The passive
group performed 4 sets of 20 repetitions exercise in 30 seconds that rest interval between 30 seconds was
completed with 3 sets passive rest. After determining the normality by Kolmogorov-Smirnov test and
homogenous variance test, independent and dependent t-tests with a significant level of α ≥ 0.05 were used.
The results indicate that after the training period, a significant difference was found in all variables exceptfatigue index in active rest group. But in passive rest group there were a significant difference in variables AT,
vVo2max, Tmax, performance of Hoff test, bench press muscular endurance and leg press strength from pre
test to post test. The results between groups indicated that there was a significant difference between two
groups in Vo2max, Tmax, AT, vVo2max, leg press muscular endurance, and mean power in benefits of active
rest group. Finally, the results showed that the resistance training with active rest causes improvements in
aerobic and anaerobic fitness of soccer players in comparison to resistance training with passive.

The purpose of current study was to investigate the spatio-temporal gait parameters and knee varus angle
during walking at different speeds in young with knee varus. 18 subjects with varus deformity classified at
grade 3 of bowleg and 17 healthy subjects, volunteered to participate in this study. The following variables
include stance, swing, double support and cycle time, cadence, stride length, angle of varus at the heel
contact, midstance and toe off when walking on the treadmill at speeds of 80, 100 and 120 percent of
preferred walking speed, were measured from using the three-dimensional motion analysis system with six
optoelectronic cameras. The results of between-group tests showed that spatio-temporal gait parameters
in the varus group is similar to the normal group. Also varus angular variables in varus group, was indicate
higher values in comparison to the healthy group, but there were no significant differences. The results of
inter-group tests also showed the knee varus angle generally increases with increasing speed, that none of
the differences were not significant. According to the results, the increase in walking speed will caused to
increase knee varus angle. Therefore, walking with speed less than the normal walking speed, probably is
a suitable solution to reduce the loads exerted on the knee joint and prevention of premature osteoarthritis
in young with knee varus.

Introduction and aim: The aim of present study was to assess the effect of six weeks Badminton training
on changes of stress and cortisol levels in non-athletic female students. Materials and Methods: In this
study estimated stress of 120 non-athlete students by stress questionnaire (HAD scale). Were measured
Among subjects who had suffered highest stress, 30 subjects with a mean age of 86/2 ± 22 years, height
56/5 ± 163 cm and weight 95/4 ± 57 kg were selected. Cortisol were measured by the bloodletting. The
subjects were divided into two experimental and control groups as homogeneous. But the control group did
not perform any activity. After training protocol variables were measured again in the same conditions. To
estimate the effect of independent variables on the dependent variable of the t-test and the independent ttest
to compare groups with a significance level (p <0/05) was used. Data were analyzed using spss and
Excel software.
Results: The results of this study showed that doing a six-week badminton practice reduces cortisol levels
(p =0.005), and decreasing stress (p =0.03) in the experimental group.
Conclusion: There was significant change in levels of cortisol and stress in experimental group.

Introduction and Purpose: Due to the importance of functional balance tests assessment with emphasis on
parameters influencing the balance including somatotype, this study undertaken to determine the reliability of
functional balance tests (static, semi-dynamic and dynamic) in endomorphe healthy women within 24-34 years
old. Methodology: 25 female endomorphe with the average and standard deviation age of 27.32±2.13 yrs,
height of 161.13±6.37 cm and weight of 58.28±8.46 kg, participated in this study. Functional balance tests
were assessed while Heath-Carter approach applied to determine the participant somatotype. All the functional
balance tests are used for each individual three times within 72 hours. Data distribution normalization are
evaluated by means of Kolmogorov-Smirnov test, while ICC was used for assessing the reliability at a
significance level of P<0.05. Results:The reliability of all static, semi-dynamic and dynamic balance tests used
in this study was confirmed with an endomorphe type body. Assessing static balance, the Stork and Angel
tests; semi-dynamic balance, Star Excursion Balance Test test; and dynamic balance, the Timed to Get Up
and Go and Tandem Walking tests got very good reliability level (ICC>0.80

High-intensity interval training (HIT) induces skeletal muscle metabolic and performance adaptations that
resemble traditional endurance training despite a low total exercise volume. On the other hand, fatty acid
oxidation is increases in skeletal muscle with endurance training. This process is regulated in several sites,
including the transport of fatty acids across the plasma membrane. The transportation across this membrane is
recognized to be primarily protein mediated. Therefore, the purpose of this study was to determine the effect of
low-volume high intensity interval training on protein content of sarcolemmal fatty acids transporters (FAT/CD36
and FABPpm) in young men. Twenty recreationally active young men were assigned to a HIT (n=10, 19.3 yr old,
67.2 kg body wt, and 172.7 cm ht) or Control (n=10, 19.7 yr old, 65.9 kg body wt, and 174.4 cm ht) group. HIT
group performed three training sessions per week over 4 weeks. Each session consisted of 8-11×60 s intervals
at ∼100% of peak power output elicited during a ramp VO2peak test separated by 75 s of recovery. Skeletal
muscle (vastus lateralis) biopsy samples were obtained before and after training. HIT increased (17.5%)VO2peak (p<0.05). Also, after 4 weeks low-volume HIT, sarcolemmal content of CD36 and FABPpm increased
14 and 25 percent ,respectively (p<0.05). Therefore, the results showed that the practical model of low-volume
HIT could increase aerobic capacity and sarcolemmal content of CD36 and FABPpm. The increase indicates
that the facilitation of in muscle fatty acid transportation can be adapted which in turn increases the fat oxidation
capacity.

The purpose of this study was to investigate the effect of soccer specific functional fatigue on hip and knee
joints angles during landing in professional players.15 soccer players with at least 2 years experience in
Kerman soccer clubs were selected randomly. To evaluate the lower extremity kinematics following
jumping and soccer specific- heading, three cameras (with50Hz) were used. To cause fatigue in subjects,
specific functional protocol similar to specific bangsbo soccer was used and Quantic sport v21 soft ware
was administrated for kinematic analysis of the recorded films. To statistical analyzing of data, descriptive
statistical methods, and paired-t test were administrated at α=0.05.Finding revealed that hip and knee
angles in sagittal and frontal plane in landing is influenced by functional fatigue. This results has been
reducing knee and hip flexion angles and increased varus in knee joint. Results demonstrated a more
erect landing posture due to a decrease in hip and knee flexion angles in the post fatigue condition.
However, functional fatigue significantly decrease lower extremity control ability in male soccer player
during landing.

One of the most important success factors in most athletic competitions, receiving aerobic power (speed,
agility and jumping) high. Basketball is a great combination of short and long term activities that depend on
aerobic fitness. Anaerobic fitness of many players during the match determines tactical the performance.
The purpose of the present study to investigate the effects of strength exercises on anaerobic power and
some the variables related Traband it. The subjects consisted of 30 basketball players Young, randomly into
two equal groups of 15 subjects (experimental and control) were randomly assigned to 6 weeks and 3
sessions the Exercises were done in a week. To analyze the data, independent samples T-test and paired
sample T-test used at a significance level p ≤ 0/05. Later for six weeks of exercises, significant differences
between the records obtained from the anaerobic power the variables (speed, agility, vertical jump) were
observed between the two groups. The present study showed that the strength exercises with the variables
Traband improve anaerobic power in young basketball players and And according to the results of seem to
exercises Traband useful method for improving performance of the anaerobic the athletes.

The aim of the study was to compare the electrical activity pattern of major muscles involved in handball
triple shooting in two groups of adolescents and adults. Ten adolescent elite handball players playing in
national club league (16.4 ± 0.69) and 10 adult handball players (23.55± 2.69) participated in this research.
They performed triple shooting و assuming in a match situation and electrical activity of the Biceps brachii,
Triceps brachii, pectorialis major muscles and three anterior, middle and posterior parts of deltoid was
recorded using surface electromyography. Parameters related to the muscular activity pattern, including
time, peak, action amplitude and contraction sequences were obtained. The results of t-student statistical
test for two independent groups (p≤ 0.05) shown that there were no significant difference between time,
peak and electrical activity amplitude variables between groups. It seems the factors such as experience in
adolescent athletes, better utilization of muscle and being close to the end of puberty makes no difference
between adolescents and adults.

Take-off is the critical phase of the long jump event. The aim of this study was to explore the relationships
between different variables and success in take-off. 37 trials performed by 8 long jumper, participants in
fourth indoor Asian senior athletics championships held in Tehran, with personal best average of 7.68±0.28
meter were recorded at 300 Hz. Five speed-related, five technical and four strength-related variables as well
as an anthropometric variable were measured using motion analysis software. More gain in vertical velocity
and less loss of horizontal velocity are considered as two criteria of take-off success and their relationships
with other variables were determined through correlation and regression analysis. Significant level of 0.05
was set. Some variables of all four groups were significantly correlated with success criteria. These variables
along with some others were entered in regression equations. The results emphasized on dominant role of
the technique and approach velocity and represented the effect of anthropometric characteristics on success
in takeoff. Furthermore eccentric strength of knee extensors was shown as the main strength factor in this
performance.

Introdiction and Aim: Nowadays, due to the epidemic of sports supplements, the effects of these
supplements on athletic performance require analysis and evaluation.The aim of the present study was to
investigate the effect of arginine supplementation for one week on oxygen uptake kinetics and time to
exhaustion in female taekwondo athletes.
Method: In this semi-experimental study with pretest – posttest design, eighty female taekwondo athletes
(age: 19.88±2.33 y, height: 167.53±6.04 cm, weight: 60.98±2.4 kg) were randomly assigned to argenine
supplementation (n=9) or placebo (n=9) groups. Subjects performed the incremental test (initially, the work
load 50 watts and 30 watts increase in workload every minutes, as long as subjects will be able to maintain
the highest pedal rate and the failure to reach). To simulate a taekwondo match day test session consisted
of three maximal incremental test intervals (1 to 2 hours). The experimental group was supplemented with
6g arginine powder and placebo group received 6g microcrystalline cellulose each day for one week.
Seven days after, post test accordingly pretest was used by all subjects. Pulmonary gas exchange was
measured by gas analyzer to breath-by breath method. Oxygen uptake kinetics variables (oxygen deficit,
time constant 1, time constant 2) were evaluated by gas analyzer with breath-by breath method. Data was
analyzed using two ways ANOVA.
Results: The time to exhaustion was extended following consumption of arginine (p<0.05). Also the
findings showed that arginine supplementation resulted in a speeding of the oxygen uptake kinetic (oxygen
deficit, time constant 1, time constant 2) (p<0.05).
Conclusion: It seems that arginine supplementation improves oxygen kinetics factors and time to
exhaustion in female taekwondo athletes.

The purpose of this study was the effect of eight weeks of circuit training on the Irisin levels and
the Insulin Resistance Index (HOMA-IR) in overweight women. Materials and Methods: In this study 22
overweight women voluntarily were chosen (Age 26.04±4.43 yrs, BMI 29.35±2.53 kg/m2) and were divided
to two groups of control (n=11) and experimental (n=11). In the experimental group, subjects performed
circuit training for eight weeks and four times per week. Blood sample was taken before and 48 hours after
the last training session. Statistical analysis at the level of P<0.05 was done. Findings: After eight weeks of
training, the level of Irisin in experimental group significantly increased while the HOMA-IR had a
significant reduction (p<0.05). Also Pearson correlation co-efficiency test shows that there is a reverse
relationship between irisin and HOMA-IR (P≤0.05). Conclusion: It appears that circuit training improves
body composition and metabolic disorders such as insulin resistance through Irisin induction in overweight
women.

The incidence of lower extremity injuries in young soccer players is high, but the risk factors for injuries are unknown. Thus, the aim of this study was to investigate relationship between static lower extremity alignment and injuries in adolescent soccer players. Four teams (78 players) playing at Tehran Asia vision adolescence primer league (14-16 years old) participated in this study. Before entering the season Navicular drop, quadriceps angle, knee hyperextension, genu varum and body mass index was measured. Players were monitored for musculoskeletal injuries through a season (7-month period). overall injury rate was 8.7 injuries/1000 player-hours (95% CI=7.01-10.10). Logistic regression modeling indicated that Navicular drop in preferred foot (OR=4.5; p=0.001), Q angel in preferred leg (OR=2.77; p=0.048), and genu varum (OR=4.06; p=0.021) were all associated with injuries but no association was found in other parameters. Players had an approximately 4.5 times greater chance of suffering a lower extremity injury if they have Navicular drop greater than 1.5 centimeter and approximately 2.77 times greater chance of suffering injury if they have Q angel greater than 15.5 degrees. These findings show that multiple anatomic measures such as Navicular drop, genu varum and Q angle can predict soccer players’ injuries. Results of this study are valuable for coaches and players for injury prevention.

Introduction and Objectives. The trajectory of center of pressure (COP) during the stance phase of gait is considered as an important parameter in assessing of dynamic balance, foot and ankle function and effectiveness of shoe and orthotics. The aim of this study was to determine the COP trajectory during stance phase of gait in healthy males and females, by means of Pedar-X plantar pressure measurement apparatus.Methods: 15 healthy adult females who didn’t have any history of injury that altered their normal gait pattern and trajectory of COP, participated in this study. The coordinate of COP in transverse (X) and vertical (Y) axes were measured using Pedar-X system. The stance phase of gait divided into the four sections by key points of acceleration vector in Y direction and then position, velocity and acceleration of COP at these portions were computed. To statically analysis, Descriptive statistic (Mean and standard deviation), Pearson correlation coefficient and ICC coefficient were used  (P≤0.05). Results and Discussion: The results indicated that during stance phase of gait, COP moves forward and medial in Y and X axes, respectively. Significant, strong but negative correlation seen between COP coordinates in X and Y axes. High Inter Class Correlation also showed between trials reliability for Pedar-X system in estimation of COP coordinates. Conclusion:  The results of this study could be used as a standard norm of trajectory of COP in healthy adult subjects

The aim of the present research is comparing the effectof periodic trainingin hypoxic and normoxic conditions on anaerobic performance of athletes .Subjects of this research were 16 male volunteer students.Subjects were divided to two groups of eight by exercising in hypoxic condition(H 3300) normocytic.Anaerobic performance (peak power, average power) through the Wingate test and lactate concentration were measured before and after the Wingate test.After 24 hours in hypoxic condition,and after 48 hours in normoxic condition the measures of W _max  were determined.The intensity of exercises in both groups (one minute with intensity of 80% -85% W_max, and two minutes with 50% W_max) and exercise duration (30 minutes)were equalized. The training program consisted of 12 sessions in a row. After that the pre-test variables were measured again .After testing the normal distribution given by Kolmogorov – Smirnov test, dependent and independent t-Test with a confidence level of 0.05 ≥ p showed that this training improved aerobic performance in both groups, also five minutes after the Wingate test lactate concentration was decreased in both groups, but there was no difference between the 12 sessions of the periodic training in hypoxic and normoxic conditions on anaerobic performance. So it can be stated that the training used in this study can improve the anaerobic performance, but the severity and duration of hypoxia used in this study was not so much to improve anaerobic performance in hypoxic group more than normocyticone

Objective: The aim of this study was to investigate the effect of non- stability surface of support leg on the instep kicking kinematics in soccer players. Materials and Methods: 30 male soccer players participated in this study. After the measurement of static and dynamic balance tests by the Biodex System, 20 players were selected who were at a desired level of the balance. Data were recorded using the three- dimensional motion analysis system with 6 optoelectronic cameras (200 HZ). The kinematic parameters in three critical moments of kicking (Forward swing of hip, Contact to ball, Follow through) were compared by using repeated measures of variance and independent t- test (0/05). Results: The results showed that the values of maximum angular velocity and displacement of hip and velocity of ball at the kicking over stability surface was significantly higher from the kicking over non- stability surface. Conclusion: These results indicate that the kicking over non- stability surface causes the lower of kinematic parameters in the more of the kicking skill phases and the movement prime velocity of ball

Motion analysis systems are useful and effective equipment in biomechanics research. Unfortunately these systems are available for few researchers because these are expensive equipment. The aim of this study was to design and validation of a practical and inexpensive software, to determine the exact markers position in space and compute the kinematic of movement. In designing the software, the exact image processing algorithms and Direct Liner Transformation (DLT) method were used to calculate markers position in space. To validate the software, the markers position in static, dynamic, linear, angular, 2D and 3D conditions were calculateted by other standard tools and compared with software outputs using Mann-Whitney U test and no significant difference were observed. The validity and reliability of the software was assessed using Pearson Correlation Coefficient and Intraclass Correlations Coefficient and during all test conditions, very high levels of these coefficients were found (≥0.97). In a nutshell, present software, with features such as automatic tracking markers, inexpensive price, the possibility to outdoor use and image processing in 2D and 3D conditions, is valid and reliable software for kinematics analysis

Homocysteine and insulin resistance in postmenoupausal women rises due to decrease in estrogen, low mobility and weight gain which increase the cardiovascular diseases. The aim of this study was to examine the effects of aerobic exercise training status on response of homocysteine and insulin resistance to aerobic exercise in active and nonactive obese postmenopausal women. Therefore, 21 obese postmenopausal women with the age of 48 - 65 yrs voluntary participated in the study and assigned in active (n=11) and nonactive (n=10) groups. Aerobic exercise was performed with 70-75 percent of maximum heart rate. Blood sample was obtained before and after exercise, and 10 hours following fasting. Results showed that baseline levels of ​​homocysteine (p= 0.003) ​​and insulin resistance (p=0.003) were significantly lower in active subjects compared with inactive ones. However, homocysteine level was significantly (p=0.028) lower in active than to nonactive subjects following aerobic exercise. It can be concluded that regular aerobic training improves insulin resistance and homocysteine levels in obese postmenopausal women, however, a session of moderate aerobic exercise could not influence on insulin resistance. Although, homocysteine response was higher in active group. It seems that changes manner of two variable to aerobic exercise is different

Chronic ankle instability has defined as recurrent ankle sprain, so that 40% of injured athletes after acute injury despite of receiving of adequate rehabilitation, suffering from this instability. The purpose of this study is investigate of postural sway’s risk factors proportion in jump-landing and lateral hopping tasks, in prediction of chronic ankle sprain occurrence. 25 ankle sprain injured athletes and 25 healthy athletes participated in this descriptive-analytic study. Six variables (area of sways, path length and velocity of sways in jump-landing and lateral hoping tasks) were measured as predictor variables, and we used to Logistic Regression test for predicting. The results of study showed that path length and velocity of sways in jump-landing, area and path length of sways in lateral hopping had statistical significant proportion in classification of injured and healthy groups, and the model classified about 77% cases correctly. Therefore, athletes with ankle sprain history have less control of posture than healthy subjects in jump-landing and hopping tasks and have higher risk to getting recurrent ankle sprain. Also subjects with chronic ankle sprain have less control of posture in frontal plan

The aim of the study, study of Changes in adiponectin, leptin, and plasma lipid profile of Inactive men the  result 24 session, playing futsal. In this study, 20 healthy men 20 to 30 years old, the experimental group (age: 23/5±2/58, weight: 69/36±14/48, body composition: 22/82±4/41) of controls (age: 24/6±2, weight: 68/22±12/71, body composition: 21/99±3/58) inactive randomly divided into control and experimental groups. Experimental groups in each session, indoor futsal training program for eight weeks and will run three sessions per week, while the control group had normal activity. Before the training program, and 48 h after the last session of play, 5 ml blood samples for measurement of adiponectin, leptin, and plasma lipid profile, blood was collected from the participants. After 48 hours of the last training session before the test was re-sampled in the same conditions. T-test results showed that exercise increased adiponectin and high-density lipoprotein and decreased leptin, low density lipoprotein, lipoprotein (a), triglycerides and cholesterol are, however, differences in adiponectin was not significant (P≤0.05). Overall, this study can be taken that these exercises in a short period of eight weeks futsal, adiponectin does not cause significant changes but the significant changes in leptin, high-density lipoprotein, low density lipoprotein, lipoprotein (a), triglycerides and cholesterol in the blood plasma.