haider sadeghi

Cardiovascular disease is one of the most common causes of death in the world and its prevalence increases with age. For the purpose of cardiac rehabilitation after heart disease, performing exercise training causes functional and structural adaptations in patient’s cardiovascular system and consequently reduces mortality from related diseases. Therefore, the aim of this study was to investigate the effect of two methods of aerobic and combined exercise training biomechanics of blood in middle-aged patients after bilateral femoral artery coronary bypass grafting surgery.

In this semi-experimental study with a pre-post test design, 68 middle-aged men (mean age 56.19± 1.26 years) were studied after bilateral femoral artery coronary bypass grafting surgery. Subjects were randomly and availably divided into 3 groups: aerobic (n =20) and combined (aerobic + resistance) (n =20) exercise training, and control groups (n =28). Subjects in the intervention groups performed 8 weeks of training/3 sessions per week. Each training session in aerobic and combined groups was considered for 40 minutes with the intensity of 70-85% heart rate reserved, and 60 minutes with the intensity of 40-80% one repetition maximum for each patient, respectively. In order to analyze the data, Leven, MANOVA and Bonferroni statistical tests were used at the significance level of P≤0.05.

The results of one-way MANOVA test showed that the levels of functional capacity, ejection fraction and maximal oxygen consumption were increased significantly after aerobic and combined exercise training compared to control group (p <0.05). However, Bonferroni post hoc test showed no significant differences between functional capacity, ejection fraction and maximal oxygen consumption post-test levels in aerobic and combined exercise training groups (p> 0.05).

the findings of this study show that both aerobic and combined exercise training can improve the heart functional variables in middle-aged patients after bilateral femoral artery coronary bypass grafting surgery, and this improvement levels appears to be independent of the types of training.

Considering the role of fascia as a viscoelastic matrix that surrounds muscles, bones, organs and nerve fibers, and its effects on human motor function, including flexibility, strength, resistance to pressure and injuries, in the present systematic review, the effects of stretching, strengthening, endurance, and combination of endurance-stretching training on fascia function were investigated.

After reviewing articles in major databases, such as Pubmed, Science Direct, Magiran, Noormags, and SID, using the words Myofascia, Fascia and Connective tissue, a study was conducted with over 55 articles published during 1984 to 2018.

All findings in the field of stretching, strengthening, endurance, and resistance-stretching exercises emphasize the positive effects of these exercises on fascia's fitness and function. Stretching and endurance exercises increase the stiffness and elasticity of the fascia. Strength and combined resistance-stretching exercises increase stiffness and reduce hysteresis of the Fascia.

With reegard to the positive effect of exercise training on facia performance, it is sugested that athletes perform the facial training along with muscle strength and cardiovascular endurance training to increase facial readiness and prevent injuries. Considering the results of the present survey, more studies are needed to be carries out on facia and its effect in enhancing performance of skills, sport injuries, and where the effect of exercise and/or performance perturbations is the case.

Performance of an athlete reduces as the time of activity increases; consequently, his landing quality is influenced by fatigue. In particular, fatigue has effects on the sportsman’s control posture and the biomechanics of his lower limbs. Moreover, landing puts more stress on these joints than jumping does, and leads to much more possibility of injury. The main objective of the present study was to investigate the effect of one stage of exhaustive local fatigue on the mechanics of the joints of the lower limb in semi-professional sportsmen during their single-leg landing.
A total of 30 young, semi-professional basketball players in Alborz, Iran, aged between 16 and 26 years, participated in the study. The biomechanical data were recorded using motion analyzer and force plate tools. To process the collected data, the numerical computing environment MATLAB was employed to extract the angles of the lower limb joints when the foot touches the ground, the maximum flexion of the knee, and the maximum normal force in the three planes of motion. The descriptive statistics is based on the mean and the standard deviation of data and the test of normality is based on the Shapiro-Wilk test. Homogeneity of data was tested using Levene’s test. The collected sets of data were compared using the repeated measures analysis conducted in SPSS, version 20.0, at the significance level of P≤0.05.
The results did not reveal a significant difference between the angles of the ankle and of the knee in sagittal and frontal planes, nor do they show a significant difference in the maximum normal force and the maximum flexion of the knee before and after fatigue (P≤0.05). The results, however, showed a significant difference between the horizontal angular changes of the ankle joint in the maximal flexion of the knee after fatigue (P≤0.000).
Fatigue may change the strategy of landing, thereby increasing the likelihood of putting more stress on the lower limb joints, especially the ankle. This may in turn harm the other joints. The horizontal angular change of the ankle joint in the maximal flexion of the knee changes the layout of these joints, particularly the knee. A deeper investigation of the effect of fatigue on the layout of the joints may help one prevent injuries resulting from exhaustive local fatigue.

One of the most commonly used human movements that plays an essential part of many daily activities and competitive or group sports is gait. Gait initiation is the first step after changing from static to dynamic status of walking and gait termination is the last step before changing from dynamic to static status. By accepting the effect of the properties of floor coverings, people's age, diseases, and musculoskeletal disorders on biomechanical parameters of human's movement, it seems that not only the pattern of muscular activity and the biomechanical parameters of gait initiation and gait termination are different from the routine gait, but these variables are influenced by individual's conditions and various surfaces on which people move on, too. On the other hand, people's imbalance and fall often occur at gait initiation or gait termination. Identifying kinematic and kinetic parameters of gait initiation and gait termination provides useful information to recognize the disturbances of this phase of gait, its pathology, and performance correction. The aim of the present study is reviewing studies carried out since the end of the twentieth century on biomechanical variables of gait initiation and gait termination in different groups and different conditions.
Searching articles was done from databases including PubMed, ScienceDirect, and Mendely, using “gait initiation, gait termination, kinematics, and kinetics” keywords. More than 300 articles on the pattern of muscle activity and biomechanical parameters of gait initiation and gait termination were found. After studying and deleting articles with similar results and articles on therapeutic protocols from the total number of articles, more than 40 articles that were directly related to the subject matter were studied.
From among the papers located, several studies were about planned and unplanned gait initiation or gait termination, gait initiation or gait termination on different floor coverings, in various age groups or people with musculoskeletal disorders.
According to the articles studied, it can be stated that different motor strategies are used at gait initiation at low and high velocities and the young and old groups always uses different muscle activity patterns in different phases of gait initiation. It seems that athletes and active people benefit from better muscle strength and shorter reaction times to prevent collapse and injury making use of compensatory mechanisms.

  The knee joint is one of the most complex and largest synovial joints in the body, which is injured in sports injuries and accidents, due to its location and the type of physical stress it entails. Also, no previous research has reviewed the difference between the mechanics of patients' and athletes' tissue in the form of ultrastructural and nano analysis. The present study was carried out with the aim of comparing the nano-biomechanical structure of injured anterior cruciate ligament cell between athletic and non-athletic men to improve the science of cell biomechanics and to help better the knowledge in the field of human body mechanics. In the current study, statistical samples were seven athletes and seven non-athlete men with anterior cruciate ligament injury. Tissue samples were obtained by each participants' orthopedic surgeon and they were prepared to determine the number and diameter of fibrils, roughness, and cell topography by atomic force microscopy. Finally, the obtained images and data were calculated using the Dual Scope ™ / Raster Scope ™ (SPM) software. Statistical analysis of the data was done using SPSS software set at the significance level of 0.05 running independent samples T-test. The findings showed that the nano-biomechanical structure of damaged anterior cruciate ligament cell, including the level of roughness (nm), the number of fibrils per unit, and fibrils diameter (nm), were different between athletic and non-athletic men. Also, topographic images taken from different regions of two-dimensional and three-dimensional injured ligament tissue in longitudinal and transverse sections of these groups showed some irregular makeup areas of collagen fibers, and fibrils were not in the same direction. Regarding the relative mean of athletes in the present study and also considering that the muscles around the knee area in athletes are stronger than non-athletes, the adjacent muscles removed the pressure from the ACL and caused the differences between mechanical properties of the cell and the ACL tissue among athletes and non-athlete in the present study.

Fatigue is thought to affect the anterior cruciate ligament injury risk; thus, the present study was conducted to investigate kinematics, kinetics, and active muscle control strategies of the knee joint in fatigue conditions during a landing task.
A total of 15 healthy active male individuals (age: 22.09± 3.18 years; height: 58/7 ± 177 cm; weight: 72/7 ± 71 kg) participated in the current quasi-experimental study. Sit to stand fatigue protocol was used for lower limb fatigue and kinematic and kinetic and muscle activity during normal gait before and after fatigue protocol were collected. Shapiro-Wilk test was used to ensure the normal distribution of data and paired t-test was run to compare variables at p≤0.05 level.
Increased knee flexion velocities (P=0.004), increased knee flexion angle at initial foot contact (p=0.016), and peak knee flexion angle (p According to the supportive role of gastrocnemius and hamstrings muscles and contribution of this muscle with ACL ligament at knee joint stability, it seems that lower limb fatigue can lead to ACL injury and reduction of the stability of the knee. Increased flexion angle at foot contact, reduced ground reaction force, and increased time to pike may be related to the nervous system strategy to shock absorption and reduce injury of lower limb joints.

According to the previous studies regarding the role of fatigue on performance, the aim of the present study was to investigate the effect of lower limb muscle fatigue on spatio-temporal, ground reaction forces and selected muscle activity of the gait in active young men.

A total of 15 healthy active male individuals, aged 22.09± 3.18 years, height 58/7±177 cm, and weight 71±7.72 kg, participated in the present quasi-experimental study. Sit to stand fatigue protocol was used for lower limb fatigue and kinematic and kinetic and muscle activity were collected during normal gait before and after fatigue protocol, Shapiro-wilk test was used to ensure the normal distribution of data and paired t-test was run to compare variables at p≤0.05 level.

Changes in gait variables, such as increased step width (p=0.003) and heel contact velocity (p<0.001), reduced ankle dorsiflexion (p=0.005), increased knee flexion (p<0.001), and first peak vertical ground reaction force (p=0.004) as well as a significant reduction in tibialis anterior, vastus medialis, vastus lateralis, rectus femoris, semitendinus, and biceps femoris muscle activity (p<0.05) were observed after fatigue.

The results confirmed the effectiveness of muscle fatigue on gait variables. Increased step width and heel contact velocity and reduced activity of selected lower limb muscles may increase the need for dynamic balance during fatigue and increase the risk of injury. The results of the present study may have clinical values. Falls in the elderly and children may create physical and mental effects. Hence, in designing associated exercises with these groups, it is recommended that intensity of exercises be maintained at fatigue threshold.

Delayed neuromuscular responses is among the most important lesions in individuals with Functional Ankle Instability (FAI), which indicates using the compensatory mechanisms. Since most of body movements occur in closed-kinetic chain, the distal lesions can affect the proximal sections leading to the use of compensatory strategies. The aim of the present study was to investigate the compensatory strategies during gait in individuals with FAI using inversion perturbation.
Material and

Seven healthy individuals (age 23.40± 1.70 years; weight 72.25 ± 6.14 Kg; height 176.32 ± 6.41 cm) and seven individuals with FAI (age: 24.31± 0.81 years; weight: 71.15 ± 7.21 Kg; height: 175.12 ± 4.28 cm) volunteered in the present semi-experimental investigation. Electrical activation of the peroneus longus, tibialis anterior, gluteus medius, and erector spine muscles during gait on the inversion perturbation system was measured using the wireless EMG system. Response Time to Perturbation (RTP) in electrical signals of the muscles was extracted using MATLAB and analyzed running independent T-tests (p

FAI group, as compared with the healthy group, indicated a significant longer RTP in the peroneus longus and erector spine muscles (p

The results of the current study showed that RTP differ in FAI group compared with that in the healthy group. Early recruitment of gluteus medius muscle in FAI group is indicator of using the hip-based strategy to control posture. Since the FAI individuals have lesions in muscle surrounding the ankle, ankle-based strategy is not enough to response the perturbation,; therefore, the dominant strategy for controlling the posture is hip-based strategy. Alterations in RTP are reported due to variation in the central neuromuscular control, so it is suggested that practitioners focus on detecting the compensatory mechanisms.