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Background and Objective: Patellofemoral is a pain syndrome, common among athletes and the theraputic regiment based on the improvement of muscle involved in this disorder. This study was done to compare electromyography activity of the vastus medialis obliques and vastus lateralis longus during squat with isometric hip adduction in athletes with patellofemoral pain syndrome and healthy athletes.

Materials and Methods: This case – control study was carried out on 16 national team male athletes (volleyball, handball and taekwondo) aged 30-18 years with patellofemoral pain syndrome and 16 healthy male athletes. Subjects were matched based on weight, height, age, dominant of lower extremity and voluntarily participated. Electromyography activity of vastus medialis obliques and vastus lateralis longus muscles recorded by surface electrodes at 15, 30 and 45 knee flexion degrees. Paired t test was used to compare electromyography activities in each group and One-way ANOVA and Tukey post hoc test was used to compare each muscle in different angles.

Results: There was significant differences in the activity of vastus medialis obliques and vastus lateralis longus muscles in athletes with patellofemoral pain syndrome at 45 knee flexion degree (P<0.05). There were no significant differences between the muscle activities in healthy athletes at none of the knee flexion degrees. There were significant differences in the activity of vastus medialis obliques (P<0.05) and vastus lateralis longus (P<0.05) muscles at 45 degrees in comparison with muscle activities in each group in knee flexion degrees.

Conclusion: Electromyography activity of the vastus medialis obliques in healthy athletes during squat with isometric hip adduction at 45 knee flextion is greater than other degrees and in athletes with patellofemoral pain syndrome is greater than healthy athletes.

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Background and Objective: Sphingosine-1-phosphate (S1P) is involved in regulation of proliferation, differentiation, hypertrophy and anti-apoptosis and activation of satellite cells. This study was done to evaluated the effect of 8 weeks resistance training on sphingosine-1-phosphate level and gene expression of SK1 enzyme, isoforms of MHCs in skeletal muscles of male Wistar rats. Materials and Methods: This experimental study was done on Twenty four 8-week-old 190-250 gr male Wistar rats. The rats were allocated randomly into control (N=12) and training (N=12) groups. Resistance training was done using a 1 meter height ladder with 2 cm grid with an 85 degree incline, and weights attached to rat's tails. The content of S1P present in the chloroform layer was determined by means of high performance liquid chromatography (HPLC). Determination of relative mRNA expression was performed by Real-time PCR. Data were analyzed using SPSS-17, Kolmogorov-Smirnov and independent t-test. Results: Resistance exercise training increased the total content of S1P in FHL (fast-twitch) and soleus (slow-twitch) muscles in comparison with control group (P<0.05). Resistance exercise training changed the gene expression of FHL SK1, SOL SK1, FHL MHC I, Sol MHC I, FHL MHC IIa, Sol MHC IIa, FHL MHC IIb, Sol MHC IIb, FHL MHC IIx, Sol MHC IIx in comparison with control group (P<0.05). Conclusion: This study showed that S1P level and gene expression of SK1, MHCs increased at skeletal muscles after training.

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Background and Objective: Disabilities in upper limb due to stroke are the major problems in hemiplegic patients. Recently, joystick method as new method is applied for the improvment of upper limb disabilities. This study was carried out to compare the effect of joystick in compination verses routine rehabilitation and routine rehabilitation program on hand muscles stiffness in hemiplegic patients. Methods: In this clinical trial study, 12 hemiplegic patients were randomly divided into two control and interventional groups. Subjects in the control group were received rehabilitation program with placebo joystick. Patients in interventional group were received joystick treatment with routine rehabilitation program for 10 sessions, 3 times a week. Pre and post-treatment evaluation was performed based on Wrist Robo Hab method. Results: Flextion and pronation muscle stiffness in control patients showed non significant improvement, but in the interventional group, significant improvement were observed (P<0.05). At the end of study, there was not any significant difference between control and interventional group. Conclusion: According to this finding, there was not any significant difference between the combination of joystick and rehabilitation treatment and routine rehabilitation program on the hand muscle function in hemiplegic patients.

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Background and Objective: Genuvarum is considered as one of the risk factors for the incidence of osteoarthritis. This study was done to compare the knee joint muscles activity during single leg drop landing from different heights among men with genu varum and men with normal knee.

Methods: This case – control study was done on 20 male students with genu varum deformity and 20 male students with normal knee. Genu varum deformity was measured by a kolis and goniometer. Muscle activity of lower limb was recorded with electromyography.

Results: There was significant difference in muscles activity of medialis gastrucnemius, peroneus longus, biceps femoris and gluteus medius in cases and controls (P<0.05), while no significant difference was observed in other muscles.

Conclusion: The changes in the knee normal structure might affect daily activities and possibly lead to in injuries due to physical training.

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Background and Objective: Muscles fatigue around the joint can altere the movment pattern and incrasing the risk of muscle damage. This study was done to determine the effect of hip abductor muscles fatigue on plantar pressure characteristics during stance phase of gait.

Methods:  This quasi-experimental studywas done on 22 males with age ranes of 15-21 years olds. Hip abduction protocol with 50% of one-repetition maximum was used to induce hip abductor muscles fatigue. Average pressure, plantar peak pressure, step duration and the plantar contact area in both feet distribution were collected using before and after the fatigue protocol during gait.

Results: Despite the relative reduction in average pressure, contact area and step duration and plantar increase in peak pressure after abductors fatigue, but these differences were not significant.

Conclusion: This study showed that the hip abductor muscles fatigue can not alter plantar pressure characteristics during stance phase of gait.

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Background and Objective: Strength and flexibility are the factors affecting the athlete's performance. This study was done to determine the effect of eccentric training on knee strength and hamstring flexibility in active females with hamstring tightness.
Methods: In this clinical trial study, 24 active female athletes with hamstring tight were randomly divided into intervention and control groups. For measurement of strength, including the eccentric and concentric peak torque and the time to reach the peak torque in speeds of 60 and 180 degrees per second, isokinetic dynamometer device .For measurement of hamstring flexibility, a passive knee extension test was used six weeks before and after the eccentric training of hamstring.
Results: After six weeks of eccentric training, a significant  improvement was observed in test scores of passive knee extension (PKE) test and also in the maximum torque and time to reach the maximum torque eccentric flexor knee in angular velocity of 60 degrees per second in the interventional  group compared to controls (P<0.05).
Conclusion: Eccentric training increases flexibility and eccentric strength of hamstring muscles in active females with hamstring tightness.

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Background and Objective: Proprioceptors of the plantar surfaces of the foot have less efficiency and the stimulation and reinforcement of them may be lead to reduction of falling risk. One of the methods to reinforce proprioceptor receptors in these individuals is using textured foot orthoses. The aim of this study was to evaluate the effect of textured foot orthoses on frequency spectrum of lower extremity muscles, stance time and comfort in individuals over age of 55 years during walking.
Methods: This quasi-experimental study was done on the 14 females and 14 males age ranged of 56-70 years with the ability to walk independently and with physical and mental health status. Subjects were compared during five conditions including without foot orthoses and using four foot orthoses (including small and large foot orthoses with two types of flexible and rigid), flexible and rigid large textured foot orthoses. The 8 electrodes were located on tibialis anterior, medial gastrocnemius, vastus medialis, vastus lateralis, biceps femoris, semitendinisus, gluteus, and erector spinae in 3 lumbar vertebrae region muscles.
Results: Frequency content of tibialis anterior and vastus medialis was significantly increased in males than female (P<0.05). Vastus medialis frequency during walking with large foot orthoses was more than walking without foot orthoses (P<0.05). The comfort level was different during flexible large textured foot orthoses condition compared with flexible small textured foot orthoses condition (P<0.05). The stance time was not significant between all conditions.
Conclusion: Increased frequency content of the vastus medialis muscle can increase the absorption and decrease the vertical loading rate imposed on the foot, which in turn reduces the risk of injury of the lower limb in older adults.

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Background and Objective: Multiple sclerosis (MS) is one of the most common diseases of the central nervous system. MS is more common among women. Gait pattern dysfunction is a relevant symptom in these patients. This study was conducted to compare the electromyography activity of selected lower extremity muscles and the ellipse area of center of pressure during unplanned gait termination in female patients with multiple sclerosis and healthy individuals.
Methods: This case-control study was performed on 10 female patients with MS (classified based on the EDSS scale) and 10 healthy subjects matched for height, age and weight. Electromyography activity of rectus femoris (RF), vastus medialis (VM), vastus lateralis (VL), biceps femoris (BF), semitendinosus (SM), gastrocnemius medius (GM) and tibialis anterior (TA) and center of pressure (CoP) recorded using foot pressure system during unplanned gait termination. Subjects were instructed to stop, as soon as possible, in response to an auditory cue delivered when the heel strike phase accidentally.
Results: Vastus Lateralis muscle activity was significantly higher in able-bodied group than patients (P<0.05), whereas in the patient group gastrocnemius medius muscle activity increased significantly (P<0.05). Also, the ellipse area of center of pressure significantly reduced in MS group in compered to able-bodied group (P<0.05).
Conclusion: Increased gastrocnemius medius muscle activity in MS patients may be due to their attempt to slow down the displacement of the center of mass to limit the tibia forward translation consequently, attempting to control balance as a strategy to limit the ellipse area of center of pressure to prevent fall.

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Background and Objective: Genu valgum is one of the most common lower limb malformations that affects on walking mechanics. This study was done to evaluate the effect of corrective exercise with Thera-band on the lower limb muscles’ co-contraction in males with genu valgum during walking.
Methods: In this clinical trial study, 24 male students with genu valgus with age range of 20-30 years were randomly divided into two control (n=12) and intervention (n=12) groups. Using the caliper, the intensity of the genu valgum was measured by assessing the distance between the medial malleolus of the subjects. Corrective exercises were performed for 8 weeks using Thera-band in interventional group. The electrical activity of selected muscles was recorded by electromyography system (biometrics ltd, UK).
Results: In the interventional group, the knee joint flexor/extensor directed co-contraction was increased significantly during the heel contact phase in the post-test than that in the pre-test (P<0.05). There was also a significant increase in knee joint general co-contraction during heel off phase (P<0.05). In the interventional group, directed co-contraction of vastus lateralis / vastus medialis muscles during the swing phase was significantly increased during the post-test in compared to the pre-test (P<0.05). During post-test, knee joint flexor/extensor directed co-contraction during the heel, knee joint general
co-contraction during heel off phase and directed co-contraction of vastus lateralis / vastus medialis muscles during the swing phase were more in the interventional group in compared to control group (P<0.05).
Conclusion: The increase of general co-contraction in the knee joint during the heel off phase reflects an improvement in activity of the knee support muscles after corrective exercises and increases balance and stability. There was also an increase in the knee joint flexor / extensor direction co-contraction, which increase the distribution of the load and pressure between the femur and tibia in the knee joint.