strength

Electromyography (EMG) biofeedback has been suggested as a relatively new approach to help resolve muscle disorders. This research aimed to evaluate the influence of 8 weeks of proximal pelvic muscle training and biofeedback on pain, muscle strength, and their EMG activity in individuals suffering from patellofemoral pain syndrome (PFPS).

This randomized clinical trial was performed on 30 young people aged 22 to 45 with PFPS. People in the intervention group (15 people) received EMG biofeedback of the abductor (gluteus medius) and external rotator (gluteus maximus) muscles along with routine physiotherapy treatments, including stretching exercises, isometric exercises of gluteal and quadriceps muscles, and conventional transcutaneous electrical nerve stimulation. In the control group (15 people), routine physiotherapy treatments were only performed on the patients. The participants of two groups were treated for 8 weeks, 3 sessions every week. Pain by a visual analog scale (VAS), maximal voluntary isometric strength (MVIC) of the abductor and external rotator muscles of the thigh with a dynamometer, and activity of these muscles, including maximum contraction, integrated EMG and onset EMG using EMG, were measured before and after the interventions.

MVIC and EMG of the gluteus medius muscle demonstrated that the intervention group had more maximum EMG activity (P=0.043) and MVIC (P=0.003) than the control group. MVIC and the maximum EMG activity of the gluteus maximus muscle showed no significant difference between the two groups. Still, the increase in the integrated EMG of this muscle in the intervention group indicated a greater increase than in the control group (P=0.0001). Moreover, people in the intervention group had significantly less pain than the group of routine exercises alone after 8 weeks of treatment (P=0.016). 

Adding 8 week biofeedback training of abductor and external rotator muscles to the routine therapeutic exercise in PFPS can lead to pain reduction, improvement of muscle strength and better performance of these muscles. This change could potentially slow down the degenerative process of the patellofemoral joint.

High-intensity functional training (HIFT) is an exercise modality that emphasizes functional, multi-joint movements that can be modified to any fitness level and elicit greater muscle recruitment than more traditional exercise. Therefore, this research aims to compare eight weeks of HIFT with high-intensity interval training (HIIT) on some factors of physical fitness, time to exhaustion, and lactate levels in officer students. In this semi-experimental research, 30 officer students with an average age of 20.04 ± 0.84 were randomly divided into 15 HIIT and HIFT groups. All the tests were done before and after the implementation of exercise protocols. Both HIIT (running-based) and HIFT (bodyweight-based functional movements) protocols were performed for 8 weeks, 3 days per week, at the intensity of 85-90% of the maximum heart rate. Basic evaluations included body composition evaluation, fatigue test, muscle strength and power test, and Army physical fitness test. The findings of this research showed that HIFT and HIIT increased respectively aerobic fitness (15.69%, 9.61%), back and leg muscle strength (16.02%, 5.02%), vertical jump (25.31%, 5.14%), push-up (19.61%, 9.39%), sit up (18.24%, 9.83%), time to exhaustion (16.21%, 14.41%) and reduced body fat percentage (18.38%, 12.18%), and lactate levels (22.89%, 14.77%). Also, HIFT was more effective than HIIT in increasing aerobic fitness (P=0.0001), back and leg muscle strength (P=0.0001), leg muscle power (P=0.0001), abdominal and shoulder girdle muscle (P=0.0001) endurance, time to exhaustion (P=0.0001), and reducing body fat percentage (P=0.002). It seems that high-intensity training, especially HIFT can improve several factors of physical fitness at the same time, and it is more suitable for tactical athletes (soldiers, firefighters, etc.) who need high physical fitness to perform their duties.

 The anterior cruciate ligament injury in athletes is associated with disorders related to balance and postural control. Poor balance is a predictor of lower limb injury in athletes. This study aims to investigate the different neuromuscular parameters that affect the static and dynamic balance in adolescent male football players with Dynamic Knee Valgus (DKV). 

 This is a correlational study. Participants were 83 adolescent male football players with DKV (age: 12.63±0.72 years, height: 1.69±0.07 meters, weight: 23.23±7.74 58 kg, BMI: 20.32±2.38 kg /m2), who were selected using a purposive sampling method. The presence of DKV was assessed by the squat test. The strength of the trunk and hip muscles was assessed by manual muscle testing (MMT), trunk endurance by the McGill test, and range of motion (ROM) of hip and ankle joints by a goniometer. Moreover, the static and dynamic balances were evaluated by the Bass Stick test and Y balance test, respectively. The Pearson correlation test was used to examine the relationships at a significance level of 0.05. All statistical operations were performed by SPSS software, version 24.

 The results of the present study showed a significant relationship between static balance and the study parameters (P≤0.05) except for trunk flexion strength (P=0.16) and ROM (P<0.05), hip flexion ROM (P=0.83), hip extension ROM (P=0.96), hip abduction ROM (P=0.77) and ankle dorsiflexion ROM (P=0.94). The dynamic balance at anterior-posterior direction had a significant relationship with trunk endurance and left-side plank (P=0.07) and strength (P=0.05), but not with plank test score (P=0.45). The dynamic Y balance at posteromedial direction had a significant relationship with all variables except for 60° flexion (P=0.40), plank (P=0.53), left-side plank (P=0.09), and trunk extension strength (P=0.23). The results of the study also showed the significant relationship of dynamic balance at posterolateral direction and the total score of Y balance test with total trunk endurance test score (P=0.03, P=0.003) and right-side plank (P=0.005, P=0.001). Moreover, trunk extension strength and hip strength variables had a significant relationship with posterolateral dynamic balance and total Y balance test score (P≤0.05). Furthermore, the ROM of ankle dorsiflexion had a significant relationship with balance at the posteromedial (P=0.03), posterolateral (P=0.02) directions and the total Y balance score (P=0.02). 

 Static balance of adolescent male soccer players with DKV has a significant relationship with trunk endurance, trunk strength and thigh strength. There is a significant relationship between dynamic balance and trunk endurance, trunk strength, hip strength, and ankle dorsiflexion ROM.

 The aim of this study was to investigate whether the application of the integrated neuromuscular inhibition technique combined with Electric stimulation can provide faster and greater improvement in maximum strength and isometric of the neck muscles in patients with chronic mechanical neck pain.

 The current research was a semi-experimental type with a pretest-posttest design. For this purpose, patients with non-specific chronic neck pain in Tehran were randomly divided into two experimental groups (n=17) and a control group (n=17). Pain, disability, strength and endurance of neck muscles before and after eight weeks of intervention were measured using visual pain index, neck disability index, dynamometer and craniocervical flexion test, respectively. Repeated measures analysis of variance and paired T-test and one-way analysis of variance were used to analyze the data.

 The results of the paired t-test and one-way analysis of variance did not show significant differences between the group and the out-group in the three groups, in contrast, the combined neuromuscular inhibition technique group with electrical stimulation showed a greater clinical effect size than the other two groups.

 According to the clinical effects reported for the combined neuromuscular inhibition technique with electrical stimulation in patients with neck pain, using this method as a complementary method in improving pain, disability and increasing the strength and endurance of neck muscles in patients with chronic neck pain Non-specific is suggested.

Background and Aims Dynamic knee valgus (DKV) is an abnormal pattern of movement or abnormal alignment of the lower limb that causes changes in lower limb function in the frontal plane and absorption of excessive reaction force by the knee ligaments during sports activities, which can increase the risk of anterior cruciate ligament injury. This study aims to compare the balance, strength, and range of motion (ROM) of hip and ankle joints in volleyball players with and without DKV.Methods This is a quasi-experimental and causal-comparative study. Participants were 60 volleyball players (30 with DKV and 30 without DKV). The tuck jump test was used to evaluate their DKV. The ROM of knee and ankle joints was measured using a goniometer, while the isometric strength of the hip and ankle muscles was determined using a hand dynamometer. Then static and dynamic balances were evaluated by the Stork test and the Y balance test, respectively. Independent t-test was used to compare the means of variables between the two groups in SPSS  software, version 24.Results The results showed a significant difference in static balance (P=0.005), dynamic balance (P≤0.05), hip abduction strength (P=0.03), hip external rotation strength (P=0.01), and ROM of ankle dorsiflexion (P=0.03) between the two groups, where those without DKV performed better. The difference in other variables was not significant between the two groups.Conclusion The results indicate the importance of improving hip abduction and hip external rotation strength as well as the ROM of ankle dorsiflexion for reducing the DKV, which should be considered in designing training protocols.

Background and Aims

The present study aims to investigate the effect of a neuromuscular training program on knee valgus angle, and range of motion (ROM) and muscle strength of hip and ankle in male adolescent football players with dynamic knee valgus (DKV). Valgus knee is one of the most common neuromuscular abnormalities that is involved in causing non-contact damage to the anterior cruciate ligament (ACL).

This is a quasi-experimental study. Participants were 25 adolescent male football players with DKV who were purposefully selected from Shahin Football Academy in Amol, Iran and randomly divided into two groups of control and training. The existence of DKV was assessed by Squats test and the valgus angle were assessed by jump-landing test and Kinovea software. The abduction and external rotation strength and ROM of hip and the dorsiflexion and plantarflexion strength and ROM of ankle were evaluated with Manual Muscle Testing and a goniometer, respectively. After performing the pre-test assessments, the subjects in the training group performed neuromuscular training for 8 weeks, while the control group also participated in the physical fitness program of Shahin Football Academy. At the end, assessments were performed again in two groups. To examine the differences, repeated measures analysis of variance and Bonferroni post hoc test were used in SPSS software, version 24. The significance level was set at 0.05. 

The results showed a significant difference in knee valgus angle (P=0.001), abduction ROM of hip (P=0.01), external rotation ROM of hip (P=0.01), dorsiflexion ROM of ankle with knee extension (P=0.001), dorsiflexion ROM of ankle with knee flexion (P=0.001), hip abduction strength (P=0.002), hip external rotation strength (P=0.01), and plantarflexion strength of ankle (P=0.03) between the control and training groups. However, the results showed no significant difference in plantarflexion ROM of ankle and dorsiflexion strength of ankle (P>0.05). After one month, the results showed the sustainability of the effect of training on abduction and external rotation ROM of hip, dorsiflexion ROM of ankle with knee extension and flexion, and dorsiflexion and plantarflexion strength of ankle.

The neuromuscular training can reduce the risk of non-contact ACL injury in male football players with DKV by improving strength and ROM of hip and ankle.

 Low back pain (LBP) is a common musculoskeletal disorder whose study on adolescents is important because it causes chronic, severe, and recurrent back pain in adulthood. This study aims to compare the trunk endurance and strength and balance in female high school students with and without chronic LBP in Qazvin, Iran.

This is a comparative study. Participants were 196 female high school students including 98 without LBP (Age=16.22±2.79 years, Height=1.60±0.05 m, Weight=54.83±10.17 kg, BMI=21.06±3.35 Kg/m2) and 98 with LBP (Age=16.01±0.84 years, Height=1.62±0.06 m, Weight=56.76±10.50 kg, BMI=21.59±3.57 kg/m2). To measure static and dynamic balances, we used the Stork and Star balance tests, respectively. The flexion and extension strength of trunk were measured by Manual muscle test. The flexion and extension endurance were measured by 60-degree flexion test and modified Biering-Sorenson test, respectively. Data analysis was done using independent t-test done.

 There was a significant difference in the flexion strength and endurance of the trunk (P=0.005), the trunk endurance ratio (P=0.004), trunk extensor strength (P=0.02), static balance (P=0.004) and total dynamic balance (P=0.02) between the two groups.

 Strengthening of trunk muscles is recommended to prevent or reduce LBP in female high school girls. Periodic examination of postural disorders and imbalance in trunk muscles is also recommended to avoid postural problems and the resulting pain.

Muscle imbalance and its amount and extent among opposing muscle groups is one of the important risk factors in causing musculoskeletal injuries. The aim of the present study was to evaluate the extent and rate of strength imbalances among opposing muscle groups of elite athletes.

To conduct the present review, the search history was searched through electronic search engines over the past two decades (2000 to 2020) at PubMed and Google Scholar. The keywords "Muscle", "Imbalance", "Athletics", "Muscle Imbalance", "Muscle Strength", "Rate", " Elite" are used for the search, along with related synonyms. Also, to search for Persian articles, the Iranian Magazines Database (MAGIRAN), the University Jihad Scientific Database (SID), the Islamic World Science Citation Database (ISC), the Iranian Medical Sciences Information Database (IRANMEDEX) and the Iranian Medical Library (MEDLIB) were used. Selected articles were obtained by considering the inclusion and exclusion criteria of the research.

Considering the inclusion and exclusion criteria of the present study, 28 articles (including 26 English articles and 2 Persian articles) were selected. The findings showed that in the knee joint, the ratio of opposite muscle imbalance (agonist / antagonist), for hamstring muscles to quadriceps (H: Q) were 63.2% and 61.8% respectively. These values ​​in the hip joint for abductor to adductor muscles (ABD: ADD) were 89.2% and 75.4% respectively. Mean of these values ​​in the ankle joint for dorsiflexor to plantarflexor muscles (DR: PL) were 35.3% and 35.6% respectively. The mean these values for inverter to aviator (I: E) muscles were 83.5% and 77.8% respectively. These values ​​in the shoulder joint for flexor to extensor muscles (FL: EX) respectively; were 76.8% and 72.8%. For external to internal retinal muscles (ER: IR) respectively; were 63.8% and 70.5%. The mean of these values ​​in the elbow joint for extensor to flexor muscles (EX: FL) respectively; were 92.3% and 91.6%. The mean of these values ​​in the scapular joint for the scapular to proximal scapular muscles (RT: PR) respectively; were 88.1% and 77%.

The results showed that in the evaluation of muscle imbalance in different groups in the upper and lower limb of elite athletes, certain relative values can be considered as quantitative and reference values. This reference is used to find out if the differences in muscle strength are such that they are considered muscle imbalance. Also, in assessing muscle strength imbalance, application of the isokinetic assessment method with the technique of 60 degrees per second is more beneficial. To conduct future studies in the field of muscle imbalance assessment, researchers recommend that in addition to strength imbalance, other aspects of muscle imbalance such as muscle length, flexibility, joint range of motion, muscular endurance, and structural profile of elite athletes should be considered.

 Low back pain is one of the most common musculoskeletal problems that comes with huge costs and has been reported as one of the main causes of disability. The purpose of this study was to compare eight weeks of opened and closed chain exercises on strength and range of motion of lower limb in female volleyball players with chronic nonspecific low back pain.

 The quasi-experimental research method with the pre-test and post-test was employed in the study. The study population consisted of all Between female volleyball players with nonspecific chronic back pain of Shiraz city, with an average age of 20 to 30 years, among whom 24 participants were selected by purposive sampling. After filling out the Quebec, diagnosis and confirmation of orthopedic physician, the participants were divided into 2 groups of 12 participants as intervention group 1 (opened chain exercises) and 12 participants as intervention group 2 (closed chain exercises). Participants strength was evaluated by employing Dynamometer and the range of motion by utilizing Modified Schober test as pre- and post-tests. The covariance test was utilized to analyze the data in SPSS-22.

 In the intervention group 1, the mean score (standard deviation) of the range of motion increased from 14.9 (1.4) in the pre-test to 16.1 (1.7) in the post-test, and in the intervention group 2, from 15 (1.1) in the pre-test to 17 (1.2) in the post-test (P<0.001), both training protocol increased range of motion. In the intervention group 1, the mean score (standard deviation) of strength increased from 63.3 (4.3) in the pre-test to 74.2 (4.2) in the post-test, and in the intervention group 2, from 64 (4.1) in the pre-test to 74.6 (4.1) in the post-test (P<0.001), both training protocol increased strength. And the results of analysis of covariance showed there was no difference between the exercise groups of open kinetic chain and closed kinetic chain in terms of range of motion and in terms of strength and by controlling the effect of the pre-test.

 The results revealed that the open and closed kinetic chain exercises of this study are effective in improving strength and range of motion by strengthening the muscles that are often associated with spine and pelvic control. More precisely, the results of the present study confirmed the effect of open and closed kinetic chain exercises on strength and range of motion in the participants, if none of the training methods was superior to the other.

The present study aims to compare the effects of two types of hopping and strength-balance exercises on the balance and strength of selected muscles in athletes with chronic ankle instability.

Participants were 30 male athletes with chronic ankle instability, who were selected using a purposive sampling method and randomly divided into two groups of hopping and strength-balance exercise. A questionnaire was used to record demographic characteristics and the information about the history of sports. To measure strength, a dynamometer was used. The Standing stork test and Y balance test were used to measure static and dynamic balances, respectively. Analysis of covariance and the Least Significant Difference post hoc test were used to compare the means.

There was a significant difference in the static balance (P<0.001) and the total dynamic balance between the two groups (P<0.001). The strength-balance exercise group in all directions of the Y balance test performed better than the hopping exercise group. Moreover, hip abduction strength (P=0.02) and the inversion (P=0.005) and eversion strengths (P=0.002) of ankle were significantly different between the two groups after training, where the strength-balance group had higher scores. There was no significant difference between the two groups in other factors.

Both hopping and strength-balance exercises can be effective in improving the balance and strength of male athletes with chronic ankle instability, where the strength -balance exercise program seems to be more useful due to its comprehensiveness and given that it emphasizes the improvement of balance, proprioception, trunk strength, and lower limb strength, and can have a greater effect on the fast recovery of athletes.

Advances in new communication technologies have created a good environment for the provision of various services. Due to the importance of using new communication technologies in health care, this study was conducted to identify opportunities, threats, strengths, and weaknesses of these technologies in the field of health with a focus on rare patients.

This qualitative study was conducted with the participation of 40 experts and specialists in the field of communication and health, and a number of rare patients. The sampling method was snowball sampling and semi-structured interviews continued to the point of data saturation. To collect data, notes were taken and the interviews were recorded and transcribed. For accurate data analysis, MAXQDA (version 12) was used.

The results of this study on opportunities, challenges, threatening factors, and strategies of using new communication technologies in the field of health led to the formation and identification of 379 initial codes, including 45 categories, which finally 4 themes of opportunities, threats, strengths, and weaknesses were extracted.

New communication technologies, regarding their potentials, could facilitate the advancement of health communication and provide better digital solutions for rare patients, who face various challenges in their treatment period and social life, as well as mental and psychological concerns and the need for information. It is recommended to determine the potentials, difficulties, and barriers associated with employing new communication technologies and then, plan, establish standards and rules, and employ these technologies accordingly

Landing mechanics, lower limb muscle strength and central stability are risk factors for anterior cruciate ligament injuries in young football players. The aim of this study was to investigate the effect of the knee control injury prevention program on landing mechanics, strength of selected lower limb muscles and central stability in adolescent male soccer players. 

The statistical population of this semi-experimental research included teenage soccer players with poor landing mechanics, 50 of whom were purposefully selected as a statistical sample and then randomly divided into two groups of experiment (number = 25 people, age = 62/ 12.70 ± 0 years, height = 1.52 ± 0.07 meters, weight = 48.87 ± 6.6 kg) and control (number = 25 people, age = 12.58 ± 0.65 years, height = 08 1.52 ± 0.0 m, weight = 50.45 ± 6.79 kg). In this study, landing mechanics were evaluated with the landing error test, thigh abduction and external rotation strength with MMT, and central stability with McGill tests at the beginning and end of the study. The subjects of the experimental group used the knee control program in the warm-up section for 8 weeks. While the control group did their usual warm-up during this time. Yeoman-Whitney and ANOVA tests were used to compare the differences between the two groups.

The results showed that the experimental group compared to the control group after the test had a significant decrease in the landing error test scores (Z = -5.62; P = 0.001) and a significant improvement in thigh abduction strength ( F = 14.26; P = 0.001), thigh external rotation strength (F = 10.74; P = 0.002) and central stability tests (F = 26.39; P = 0.001).

This study showed that the implementation of the knee control injury prevention program can improve the landing mechanics, abduction and external rotation strength of the thigh, and central stability in teenage soccer players. Therefore, it seems that the knee control program can be effective in preventing the risk of anterior cruciate ligament injuries in young male football players.

Muscle damage has always been a serious problem following accidents and spinal cord injuries. Mental imagery or motor imagery is a treatment in which a patient evokes a movement to improve performance. There are limited studies in this field, so, this study aimed at investigating the effect of mental imagery on increasing the strength of elbow flexor muscles.

This study was performed in 20 healthy individuals, non-athletes aged 22-25 years old. The strength of the elbow flexor muscles was measured by a dynamometer and a special tape measure was used to measure the hypertrophy of the biceps muscle. The experimental group performed strength training designed for the superior hand using free weights and at the same time performed this exercise mentally with the non-superior hand (three days a week/12 weeks). Mann-Whitney U test was used to compare the changes between superior and non-superior hand and Wilcoxan test was used to compare the amount of changes in maximum muscle contractile force.

Findings showed increased elbow flexor strength and hypertrophy in both the superior hand and non-superior hand.

Although real exercises were more effective in improving strength and hypertrophy of flexor elbow muscles, but mental imagery also affected muscle strength and hypertrophy as much as real exercises.

Movement is considered a system that is made up of several elements, each of which has a relatively unique basic function necessary for the production and regulation of movement. Sometimes, repetitive movement and sustained postures causes to move away from the normal state. The purpose of this study was to investigate the relationship between scapular movement impairment and shoulder girdle strength and range of motion in professional male volleyball players.

120 men volleyball players (mean ± SD, age: 23.25±3.23 years, weight: 88.11±8.14 kg and height: 192.78±8.63cm) participated in this study. Participants classified according to the obvious scapular movement impairment during scapular dyskinesis test and Kibler shoulder lateral slip test. For measure the strength and range of motion handheld power meter and goniometer were used respectively. Scapulohumeral rhythm used to measure with inclinometer. Shapiro- Wilk test was used to check the data normality. Pearson correlation (p<0.05) was used to analyze data.

The results showed, there was a significant relationship between movement impairment and range of motion of the shoulder extension (p=0.001), (r=-0.752), Internal rotation (p=0.003), (r=-0.554), strength scapula downward rotation (p=0.003), (r=-0.482), elevation (p= 0.029), (r = 0.286) and  Depression (p=0.003), (r=0.460) Scaption (p=0.003),(r =0.137), scapula protraction (p=0.001), (r=0.534), and retraction (p=0.002), (r=-0.649) and scapulohumeral rhythm 0°, 90°, 135°(p= 0.001), (r=0.583, 0.581, 0.583) and 45° (p=0.003), (r=0.580). However, there was no significant relationship between movement impairment, rang of motion of the shoulder flexion, external rotaion, adduction and abduction, strength of the shoulder flexion, extension, abduction, adduction, internal and external rotation, and horizontal adduction. (p>0.05)

According to the results pattern of repetitive movement in the sport of volleyball, in long duration may disturb the balance of natural ratio of strength, range of motion and scapulohumeral rhythm in the shoulder girdle and scapula reign.