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Background and Aim: Several stretching methods have been shown to increase flexibility of the short muscles. Previous research suggests muscle energy techniques produce increments in range of motion, but there are many variations of muscle energy techniques. The purpose of our study was to determine the efficacy of muscle energy techniques with 50% of maximal voluntary isometric contraction and 10 second hold in compared to control group.

Materials and methods: A sample of 30 female subjects (aged 20 -25 years) participated in this study. All subjects had limited hamstrings flexibility in degrees of passive knee extension. The subjects in experimental group (n=15) received 3 muscle energy techniques (50% MVIC, hold time=10 sec) for 4 weeks, whereas the control group (n=15) remained without treatment. Before and after range of knee extension was measured for all subjects.

Results: The paired t test revealed a significant differences in flexibility for experimental group (P<0.001). There was no significant difference in flexibility gains in control group (P<0.001). Treatment group had significant greater flexibility than the control group (P<0.001).

Conclusion: Muscle energy techniques with above protocol produce an increase of hamstring flexibility.

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Background and aim: With respect to attachment and mechanical relationship of hamstring and calf muscles, interaction between their function is unavoidable. Inspite of prevalence of hamstring and calf muscles shortness, there is not any statistical data about the relationship of shortness of above-mentioned muscles in Iran. The aim of this study was to verify of this prevalence.

Materials and methods: In this study 3308 healthy girls with age 3-17 years old participated. Length of calf muscles with dorsi flexion angle and hamstring with hip flexion angle (SLR) in both side were measured.

Results: The prevalence of hamstring and calf muscles shortness with together was20% in right and 25% in left side .The Prevalence of hamstring and calf muscles shortness with together in 20 district was greater than 3.The greatest amount was seen in secondary school(31.6%).               

Conclusion:The results indicated that most of subjects who had hamstring shortness, they had also calf muscles shortness, so if there is any shortness in one of them, we shouhd pay attention to shortness of the another.

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Background and aim: Muscle flexibility is an important component of physical fitness and injury prevention.

Passive Stretch can be effective in lengthening and making hamstring more flexible. Popliteal angle measurement is one of the most simple method in studying the efficiency of these methods however, in goniometry measurement, there is not any data about muscle tension and any proper judgment about flexibility.  The goal of this study is to evaluate length and stiffness of the hamstrings by Quick Release Movement before and after the passive stretch.

Materials and methods:14 men (20-30 years old) with shorted hamstring (20 degree or more ext lack in passive knee ext test by popliteal angle measurement) participated in this study. Before and after exercises, popliteal angle  and muscle stiffness  were evaluated with digital goniometer and  Quick Release Movement technique respectively. Evaluation of stiffness was performed in flexion and extension positions.

Results: A significant increase in hamstring length was observed. (P<0.05) There was decrease in stiffness in both position of flex and ext but it was significant when in extension state.(P<0.05)

Conclusion: Findings of this study demonstrate passive stretch's effectiveness in increase muscle length and lessening muscle stiffness. In addition Quick Release Movement can be a suitable method for measuring muscle stiffness.

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Background and Aim: This study was performed to compare the stiffness of hamstring and rectus femoris muscles in subjects with anterior knee pain and normal subjects.

Materials and Methods: In this non experimental and case-control study, 20 persons with anterior knee pain were selected simply from convenient sample and 20 healthy persons were selected by matching method. proximal and distal stiffness of hamstring and rectus femoris muscles were measured using an isokinetic device in the passive mode. Also, maximal concentric peak torque during flexion and extension movements of hip and knee, in two groups were compared by independent T-test and correlation analysis.

Results: There was no significant difference between anterior knee pain and proximal compartment of rectus femoris(P=0.320) and hamstring(P=0.125) stiffness, but there was significant difference between anterior knee pain and distal compartment of rectus femoris and hamstring stiffness (P<0.001). Significant relationship was found between anterior knee pain and muscles strength (P<0.001). No correlation was found between strength and stiffness of rectus femoris (P=0.356) and hamstring muscles (P=0.643) in patients group, but in healthy subjects this relationship was found (P<0.001). 

Conclusion: In patients with anterior knee pain, hamstring and rectus femoris muscles stiffness increased and muscle strength decreased. Increasing of muscle strength was effective on stiffness in healthy subjects, but there was no relation between them in patients group. Also rectus femoris and hamstring muscles possibly have different proximal and distal neuromuscular compartments.

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  Background and Aim: Since many of people in their functional activities mostly place their knee joint in flexed position, the hamstring muscles tend to be shortened. On the other hand, shortness of these muscles affect the knee joint directly and the ankle and hip joints indirectly. It predisposes the individual to musculo-skeletal injuries. Thus, by early diagnosing and treatment of it, the tension may be decreased, the relaxation increased and the development of injuries can be prevented. In order to achieve this goal, various stretching techniques are used. The purpose of this study is to compare the effects of static and PNF stretching on shortness of hamstring muscles in 18-30 years young women.

  

  Materials and Methods: Thirty 18-30 years old nonathletic women without any history of pathology in hip, knee or back were selected. They were divided into three groups with 10 women in each group(static stretch, PNF stretch and control). The two stretch groups were received stretching program five days every week for three weeks, while the control group was not.

  Results: The range of knee extension of both groups of static and PNF stretching increased (p<0/05). However there was no significant difference between these two groups (p>0/05).

  

  Conclusion: Employing of both methods (static and PNF stretching) increase the hamstring muscles flexibility. However there was no significant difference between two groups in increasing rang of knee extension.

  

  Key words: Hamstring muscles, static stretching, PNF stretching

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Background and Aim:: Muscular shortness is one of the most common musculoskeletal impairments. It may occur as a result of trauma or even a sedentary life style and cause clinical symptoms. Hamstring muscle, due to its functional roles, is prone to injuries during physical activities. Research has shown that decreased hamstring muscle flexibility may lead to lower extremity injury. The goal of this study is to compare the effects of myofascial release (MFR) and muscle energy technique (MET) effects on hamstring muscle flexibility. 

Materials and Methods: Twenty four non-athlete healthy subjects (means ± SD= 26/12 ± 5.4 Years) were randomly assigned to two groups; myofascial release group and muscle energy technique group. Passive range of motion (ROM) of knee extension was measured using a digital goniometer before and immediately after the intervention.

Results: There was a significant increase in the knee passive range of motion immediately after both interventions (in MFR group p=0.000 and in MET Group p=0.000).The amount of knee extension increase was greater in myofascial release group (p=0.023).

Conclusion: Both MFR and MET can increase hamstring muscle flexibility; however, in this study MFR has shown to be more effective than MET.

Keywords: Flexibility, Muscle energy technique,  Myofascial release technique,  Hamstring muscle