جستجوی مقالات مرتبط با کلیدواژه « اندام تحتانی » در نشریات گروه « تربیت بدنی »

This research was conducted with the aim of investigating the electrical activity of the lower limb muscles while maintaining static and dynamic balance, emphasizing the history of falls in the elderly. The research is causal-comparative and practical in terms of purpose. The statistical population of this research was the elderly who were selected in two groups with a history of falling (10 people) and without a history of falling (10 people) in a purposeful way. using an electromyography device, the activity of the right rectos femoris, biceps femoris and tibialis anterior muscles of the right and left foot was recorded during the balance test. To assess the normality of data distribution, Shapiro Wilks test was used. The data were processed using analysis of variance for repeated measure at a significance level of 0.05.The results showed that while maintaining balance on the right foot, there is a difference between the normalized EMG activity of the right and left biceps femoris muscle (BF) of the two groups, and in the TUG test, the group with a history of falling showed more activity in the right rectus femoris (RF) muscle and the right biceps femoris (BF) muscle than the nonfalling group. According to the results, the normalized EMG activity of the biceps femoris (BF) and rectus femoris of the elderly with a history of falling while maintaining static and dynamic balance is significantly higher than that of the elderly without a history of falling; The increased EMG activity in falling group can be attributed to the recruitment of more motor units for compensation of balance deficit. Considering that performing static and dynamic balance exercises increases the activity of lower limb muscles in the elderly with a history of falls, therefore, to prevent frequent falls in the elderly with a history of falls, it is recommended to strengthen the biceps and rectos femoris muscles through balance exercises in these people.

The aim of the present study was to analyze video injuries of football players in the 2022 World Cup. For this purpose, the video footage of all the World Cup games (62 matches) was examined by the researcher and the rate of injury prevalence, the mechanism of injury occurrence, the type of collision leading to injury, the time of injury occurrence and the injured area were recorded in the injury report form. According to the results, 127 injuries occurred during 62 matches or 55.96 injuries per 1000 hours of matches. The highest rate of injury happened in the last 15 minutes of the second half (75-90)(21.3%) (P<0.05).Collision was the most common mechanism causing injury (23.6 percent) (P<0.05) and the highest amount of damage occurred in the lower limbs of the players (55.1 percent) and the ankle was injured more than other parts of their body (19.7 percent) (P<0.05).Also, most injuries were caused by collisions (38.9 percent)(P<0.05). The rate of injury in these games was higher than the previous World Cup games. This can be caused by the difference in the definition of injury, the different game system, the difference in the duration and type of preparation and bodybuilding exercises, and the different methods of collecting information. Also, knowing the time of injury and the type of collision leading to injury, the main mechanisms causing injury and the most vulnerable organs during a football match is effective in designing injury prevention programs and helps players, coaches and the medical team.

TFootball is one of the sports with the highest risk of injury, with children suffering injuries at a rate of approximately 3% yearly and major injuries at a rate of approximately 0.69%. The aim of this systematic review is to examine the effects of the FIFA 11+ Kids program on injury prevention and performance improvement in preadolescent soccer players.

This review aims to gather research conducted between 2016 and 2022 pertaining to the subject of research. The present investigation uses Scopus, Google Scholar, PubMed, and Science Direct databases to perform a comprehensive search for pertinent research. The search is conducted using keywords including FIFA 11+ Kids, prevention, children, injury, lower limb, performance, and anterior cruciate ligament.

Thirty publications were retrieved using the search strategy, and thirteen were chosen for finalization and inclusion in this study based on the criteria for inclusion and exclusion. The implementation of FIFA 11+ Kids exercises in children has been shown to enhance physical fitness components such as balance, jumping activities, lower limb isokinetic strength, and knee joint proprioception. Furthermore, these exercises have been found to mitigate injuries, particularly in the lower limb, and significantly decrease associated treatment expenses.

Research indicates that the FIFA 11+ Kids warm-up training program plays a unique role in preventing lower limb injuries and improving performance, particularly if performed over an extended duration or with more training sessions per week. Therefore, it is imperative to implement this training program for football players under 14 years of age.

Running is known as one of the most popular sports for which there is no time and space limit. Recently, due to lifestyle changes, the use of treadmills for walking and running has increased. However, the biomechanical differences in coordination between running on a treadmill at different speeds have not been sufficiently addressed. The aim of this study was to investigate the effect of increasing running speed on three-dimensional changes of lower extremity joint angles in the open motor chain and swing phase.

28 elite runners participated in this study. Subjects ran on an equipped treadmill while kinematic running data was recorded for 30 seconds through a three-dimensional 12-camera motion recording system at speeds of 2.5, 3.5 and 4.5 m / s. Data were normalized based on the subjects' body mass as well as 101 time points in the running cycle. The normality and homogeneity of variance of the dependent variable were tested using Bartlett and Leven’s tests. Repeated measurement test was performed to measure the angles of the pelvis, knee and ankle between the dominant and non-dominant lower limb joints in the running swing phase.

In the range of motion of hip, knee and ankle joint, there were significant differences among all the three speed rates of 2.5, 3.5 and 4.5 on all planes.

Changes in the angle and range of motion of the hip, knee and ankle joints are significantly greater in the swing phase as the running speed increases. Due to the fact that in high-speed running, the stability of the body decreases, the central nervous system commands to increase the range of motion of the angle of the mentioned joints to regulate the structure of the body and reduce the instability in response to the applied disorders. The results also show that the ankle joint, as the closest joint in contact with the ground, helps to run faster and more efficiently by increasing changes in the angle and range of motion of the ankle joint during running, and by reducing the time of foot contact with the ground at each step. It can be concluded that this point is effective in increasing speed.

Attention can be paid to the biomechanical characteristics of running since the speed of running varies. The aim of the present study was to investigate the effects of increasing running speed on the three-dimensional kinematics of the lower limb joints in the stance phase.

The research was quasi-experimental. 27 volunteer subjects ran on a treadmill and the kinematic and kinetics data were collected through a three-dimensional system at three speed levels (2.5, 3.5, and 4.5) m/s. kinematics and kinetics data were recorded by 12 cameras (120 Hz) and force platform (150 Hz), respectively.   The stance phase was derived according to the ground reaction Force value of the force platform. Hip, knee and ankle kinematics including peak of the absolute angles in three dimensions and three speeds were calculated for further analysis. Repeated measurement with Bonferroni post Hoc tests were employed to investigate the differences between the variables in three dimensions using SPSS software (P <0.05).

The results showed that during increasing speed, significant differences were observed in frontal (2.5 & 3.5, 2.5 & 4.5 m/s) and sagittal (2.5 & 3.5. 2.5 & 4.5, 3.5 & 4.5 m/s) planes in hip as well as only in transverse (2.5 &4.5, 3.5 & 4.5 m/s) plane for knee. No significant differences were obvious in peak of ankle joints during increasing speed in all three planes.

The results of the present study showed that hip and knee joints are more susceptible to changes of kinematics behavior during running progressively. Ankle joint seems to be more stable during the progressive running situation. Coaches and athletes may also enhance their performance using the results of the present study.

The aim of this study was to investigate the effect of increasing running speed on motor ‎chain and kinetic ratio of lower limb joints‎.

The statistical population of this study consisted of healthy people and ordinary runners. A ‎group of 28 healthy male subjects, including runners who ran more than 20 km per week, ‎were selected via convenience sampling method as research sample. They were also fully ‎acquainted with running on a treadmill. Three-dimensional kinetics parameters of the lower ‎limb joints, hip, knee, and ankle, torque and the kinetic ratio of the minimum, maximum and mean values of these ‎joints at three different speeds 2/5,3/5 and 4/5 was measured by two important instruments, ‎the camera and the force plate. Shapiro-wilks test was used to check the normality of data ‎distribution and data analysis was performed using analysis of variance with repeated ‎measurements or repeated measure through SPSS software, version 22‎.

Based on the results obtained in this study, the torque ratio of hip to knee and thigh to ankle ‎joints was not significant in any of the anatomical plates and axes at three speeds (p≥0.05). ‎Also, the ratio of torque of knee joints to ankle in three speeds and three planes did not ‎show a significant difference ( p≥0.05)‎.

According to the results obtained in this study, it seems that with the knowledge of the ‎moment changes of the lower limb joints, practical solutions can be provided to reduce the ‎amount of damage when running, especially on a treadmill, to these 3 joints. ‎

The aim of this study was to compare the range of motion of lower limb joints in overweight and obese individuals.

The statistical population of the present study consisted of 25 to 45 years old working and available women in Zanjan province. These people, who included 57 people, were divided into two groups: 30 people with normal weight (mean age 31.86±6.03 years and body mass index 21.61±1.71kg / m2) and 27 people with overweight (With an average age of 35.35±6.03 years and a body mass index 27.86±1.40kg / m2). A goniometer was used to assess the range of motion of the hip, knee and ankle. After determining whether the data were normal or abnormal by Shapiro Wilk test, the normal data were analyzed through independent parametric T-test and the data which were not distributed normally were analyzed via non-parametric U Man-Whitney test.

The results showed that among the range of motion of the hip in both legs in flexion, extension, abduction, internal rotation and external rotation, the range of motion of the knee in both legs in flexion and the range of motion of the ankle in both legs there was a significant difference between dorsiflexion and plantar flexion movements in the two groups, but the difference between the two groups in range of motion in both legs was not significant in hip abduction and knee extension movements.

According to the present results, it seems that being overweight can reduce the range of motion in some movements in the lower extremities. Regarding the causes researchers have proposed various factors that need further studies.

The aim of this study was to evaluate the relationship between lower extremity alignment and endurance of core with maximal knee valgus during drop landing jump in female athletes. In the present cross-sectional study, 44 female athletes aged 16 to 26 years participated. The knee valgus angle was recorded using video camera during landing jump. Q angle, navicular drop, hip anteversion, tibia torsion, knee hyperextension and core stability endurance were assessed using standard clinical procedures. Data were analyzed by Pearson correlation test. The findings of the present study showed that there is a significant relationship between Q angle, endurance of right and left lateral flexor muscles with maximum knee valgus (P≤0.05). According to results of this study, assessing the Q angle and endurance of the lateral flexor muscles of the trunk can help identify athletes at risk for ACL injury and provide programs for the prevention of lower extremity injuries.

Surface stiffness is a factor affecting the injuries since any change in in the amount of this parameter leads to the increased applied forces. This is a quasi-experimental, causal-comparative, and applied study. The statistical population included 14 volleyball players aged between 18 and 20. The muscles’ electrical activity was recorded by an 8-channel electromyograph based on the SENIAM protocol (Surface ElectroMyoGraphy for the Non-Invasive Assessment of Muscles) on four selected muscles of the lower limb. Mean and standard deviation (SD) were employed for data description, Shapiro-Wilk test for the assessment of data distribution normality, analysis of variance with repeated measures for the effect of surface type on the research variables, and Bonferroni post hoc test was used for the assessment of differences. Furthermore, the repeated measurement test’s results revealed no significant difference between groups in terms of the peak muscle activities in Vastus lateralis muscle and Biceps femoris muscle when jumping and landing on tatami, grass, and sand (p≤0.05); however, the surfaces were significantly different in the tibialis anterior muscle and gastrocnemius muscle (p = 0.00). Besides, there was no significant difference between co-contractions in knee and ankle joint (p≤0.05); the difference was that in the knee joint, the highest average co-contraction was seen on the grass and its lowest rate on the sand, while in the ankle joint, the lowest rate was seen on the sand and the highest rate on tatami.

The aim of this study was the effect of educational intervention on gait kinematic characteristics in motor in children 3-5 years old. Twenty-four children aged 3-5 years old were randomly divided into two groups (intervention group: 12 per, and control group: 12 per). The intervention group practiced for six weeks and two sessions a week. The range of motion of the hip, knee and ankle joints was measured on the sagittal plane at the moment the heel contact the ground and the moment the toe off from the ground, before and after the intervention. Paired t-test showed that educational intervention had a significant effect on the change of lower extremity kinematic variables at the level of α = 0.05 (In the intervention group: at the moment of heel contact with the ground, the amount of dorsiflexion of the ankle increased by 35.5% after the intervention, knee flexion decreased by 20.62% and hip flexion decreased by 20%. Also, at the moment of toe off from the ground, the amount of plantar flexion of the ankle increased by 37.73% after the intervention, knee flexion decreased by 16.74% and hip extension increased by 37.61%). Based on the results of ANOVA analysis, there was a significant difference between the exercise and control groups in the kinematic variables of walking. The results showed that a linear pedagogy course is suitable for changing the kinematic pattern of walking in children 3-5 years old.

Objective :

Excessive dynamic knee valgus, as a defective movement pattern, predisposes patients to lower limb injuries. Therefore, the aim of the present study was to study dynamic knee valgus in male soccer players.

Methods :

In this review article, an attempt was made to collect studies conducted on the subject of research from 2000 to June 2021. The websites Google Scholar, PubMed, Science Direct, SID, ISC and Magiran were used and keywords related to the topic were used to search for articles.  

Results:

 According to the search method, 50 articles were found, which were finalized according to the inclusion and exclusion criteria of 12 articles. Finally, 7 articles were reported in the present study. Dynamic knee valgus condition is more common in women than men, and varus are more common with increasing age of male soccer players. Different situations during the game such as tackling, jumping, imbalance after strike to the ball and landing after jumping are also among the situations that are associated with increased dynamic knee valgus and players are exposed to knee injury. The first minutes of the halves due to the lower angle of flexion of the knee and also late in the game due to fatigue can increase the dynamic valgus and increase the risk of knee injury. 

Conclusion:

 All studies have pointed to the role of dynamic valgus in the incidence of knee joint injuries, especially the anterior cruciate ligament, so it is necessary to identify the mechanism of injury and correct the direction of dynamic valgus among soccer players.

Due to the fact that in old age, the potential for musculoskeletal abnormalities and consequently changes in biomechanical function is associated. The aim of this study was to investigate the effect of dry endurance, water and combined endurance training on selected kinematic variables of involuntary gait in men aged 75-60 years. , Water and a combination.Dependent t-test was used to compare pre- and post-test and analysis of covariance was used to compare the effect of three types of training on dependent variables. Findings showed the effect of exercise on a significant increase in normalized stride length, body center of mass displacement, range of motion of hip, knee and ankle dorsiflexion, involuntary walking, although it seems that the use of endurance training can have a positive effect on Have the kinematics of the elderly while walking.

Knowledge of the relationship between performance and range of motion, helping to design training programs, comply of individual with the needs of children is, therefore, The aim of research the relationship between some of the lower extremity range of motion and biomechanical parameters of the boys was performed. Hundred students in this study were randomly selected. After measuring the range of motion of lower extremity, test speed, power, balance and agility of the subjects were recorded. By descriptive statistics to determine the mean and standard deviation of the method of multiple correlations to assess the relationship between the selected range of motion and biomechanical parameters of subjects were used. Hip flexion by speed, hip abduction and knee flexion by balance and hip flexion, hyper adduction and ankle dorsi flexion significant positive correlation by the agility, the rate of hip and knee flexion by power a significant negative correlation and with other lower extremity range motion parameters showed a significant positive association. According to the research findings, seem to be characteristics of the children lower extremity range of motion and identify performance indicators for various athletic field, can be used.

 The sprint start is a complex skill characterized by a multi-joint and multi-plane task requiring complex muscle coordination to reach a large force exerted in the horizontal direction in a short time. Previous studies indicated that efficient acceleration over the first portion of a race is influenced by how a sprinter is positioned in the set command blocks.

 A total of 15 elite women runners participated in this study. The subjects performed three optional, and five selected sprint starts with 2-minute intervals. The Noraxon-MyoMotion device collected the kinematic data, and a continuous relative phase method was used to calculate the joint coordination pattern.

 The pattern of coordination between the lower limb joints were divided into 10 phases. There were differences between the two types of starters in the initial phases, but no difference was noticed from the fourth phase.

 Indeed, there was irregularity in the early phases of the selected start type, while in the following phases, the coordination pattern coincided, and it seems that if this process does not affect the speed and acceleration of the athlete, it can be cautiously noted that sitting in any way in the start technique will ultimately create common coordination in the joints.

 This study aimed to examine the effect of fatigue on postural balance of young women using Electromyography (EMG) of lower extremity muscles and measuring the foot plantar Center of Pressure (COP) displacement.

Participants were 10 young women (mean age, 26.4±3.01 years; mean weight, 65.5±5.75 kg; mean height, 165±2.61; BMI, 24.08±2.08 kg/m2) with no history of lower limb injury or balance problems. To evaluate their static balance, the stork test was used and the foot plantar COP was measured by force plates. To measure fatigue, three parameters of muscle power (P), median frequency of muscle (F) and Root Mean Square (RMS) of raw EMG signals were calculated. Data were analyze din SPSS V. 16 and MATLAB software using Mann-Whitney U test.

fatigue had a significant effect on P and RMS parameters (P<0.05), but did not significantly affect the F. It increased P and decreased RMS. The highest change in the P parameter was seen in biceps femoris muscle; the highest change in the F parameter was related to semitendinosus muscle; and the highest change in the RMS parameter was related to gastrocnemius lateralis and gastrocnemius medialis muscles.

 There is a negative relationship between fatigue of the lower extremity muscles and balance impairment; by increasing the level of fatigue in the muscles, balance is more impaired.

T Abstract To improve motor function, movement pattern and changes in joint kinematic parameters are investigated in different conditions. Using a treadmill in human gait analysis, makes it possible to record several steps of gait in a limited space and also controlled conditions. The purpose of this study was to investigate the consistency of the kinematic parameters of lower limb joints during walking on the ground and treadmill. Intraclass correlation coefficients (ICC) for kinematic parameters of lower limb joints of 15 healthy young male participants were calculated during walking on the ground and treadmill. The angles of pelvic, hip, and ankle were often in the range of excellent reliability (ICC>0.9) when walking on the ground, while the results were in the range of average reliability (ICC<0.7) when walking on a treadmill. Therefore, in treatment activities or research studies, considering the decrease in consistency of walking trials on the treadmill is important.

The aim of this study was to Analysis of Selected Kinetic-Temporal Variables of Lower Extremity of Elite junior volleyball players during Block Jump Skill. 30 junior volleyball players of National Team of the Islamic Republic of Iran stand on Force platform and performed block jump skill, peak vertical forces, Time of peaks, Time elapsed between peaks, time of contact, end of the landing, total landing time, Ratio between peaks and between the time of the peaks were calculated. There are significant positive correlations between Times of peaks, Time elapsed between peaks and peak vertical forces and negative correlations exist between other variables of the research. So in volleyball players great stress would be placed on lower extremity at the moment of landing. Because of increasing time of the second peak will decrease the impact force, although it is not appropriate for volleyball goals.

The risk of injury in football is high. Many researchers have introduced muscle strength as one of the most important internal risk factors, but few studies have examined the relationship between the isometric strength of muscles and incidence of injuries. Therefore, the aim of this study was to examine the relationship between isometric strength of lower extremity muscles and the incidence of injuries in football players and the power to predict these injuries. The sample of this study included 73 football players under 21 years of age. Before the beginning of the season, the anthropometric dimensions and isometric strength of lower extremity in dominant leg of each player were measured by Isokinetic device (Biodex system 4), then each player was followed up for 8 months and their injuries were recorded. The results of Cox regression test showed no significant relationship between isometric strength of the measured muscles and the incidence of injuries in lower extremity. According to these results, it is suggested that medical and technical staff of football teams use isometric tests to identify high risk players. Other strength evaluation methods such as isokinetic and isotonic strengths may be more effective.

Foot orthoses are often used to correct altered gait patterns. The purpose of this study was to investigate how foot orthoses can modify the magnitude of three dimensional ankle, knee, and hip joints kinematics during stance phase of walking in children with flexible flat feet. Three dimensional kinematic data were collected from 15 male children (age: 10.3 ± 1.5 years) suffering from flexible flat feet. In order to obtain the kinematics data, a Vicon motion capture system was used. Arch support foot orthoses were used as an intervention. ANOVA repeated measure test was used for statistical analysis (α =0.05). The results of data analysis showed that shoe insole can decrease the peak knee (P0.05). The foot orthoses used in this study were observed to have positive systematic effects on kinematic data during stance phase of walking. Therefore, using of this orthoses was recommended for male children with flexible flat feet. Moreover, the findings of this study may be used as a guidance for future researches in this field