Background and Aim: Low back pain (LBP) is the most common and expensive musculoskeletal problem in industrialized societies. One in ten people suffers from LBP once in his life. It is self-limited up to 90%, but it is common to repeat. By the way, sacroiliac joint (SIJ) is the origin of low back and pelvic pain in many cases and one of the most important elements in normal musculoskeletal function during gait cycle. Muscles are important to stabilize this joint plus to bones and ligaments. Some of the muscles (Gluteus Maximus, Biceps Femoris, Multi Fidus, Erector Spinae) contributing in gait cycle are important to transfer load through SIJ. The aim of this present study is to compare muscle activity timing during initial and mid stance phase of gait cycle.

Methods and Materials: Sixteen low back pain cases and fifteen healthy subjects participated in this study. A footswitch is placed beneath foot at the suffered side in LBP cases and dominant foot in control group. Two markers were on the 5^th metatarsal bone and lateral maleolus. Electrodes are placed on selected muscles according to SENIAM. Digital camera and EMG Datalink were turned on simultaneously and subject started to walk with his own favorite speed in a specific direction and path. Onset and time to peak of selected muscles were recorded during gait by Datalink and processed by its software.

Results: Low back pain cases showed delayed muscle onset, although it was not significant (P=0.4). Time to peak of all selected muscles in loading response event in LBP group was longer and significant (P=0.01). There was also significant difference in time to peak of all selected muscles during mid-stance event (P= 0.005) except biceps femoris muscle.

Conclusion: Delayed onset and longer time to peak during initial and mid stance phase of gait can be interpreted as a compensatory strategy to control trunk movements effectively, provide sufficient stability and transfer load to lumbar area efficiently.

Key words: Muscle activity, Low back pain, Gait, Trunk muscles, Lower Limb Muscles

Background and Aim: Postural control is the ability of maintaining of the body posture in space. Peripheral and central factors have important role in muscle fatigue. Repetitive muscle contraction leads to muscle fatigue. If strength is educed up to 30% of maximum contraction can be disturbed stance control of subjects. The objective of the present study was to compare the effect of lumbar muscle fatigue on postural control in athlete and non-athlete subjects.

Materials and Methods: Fifteen men as athlete subjects and other fifteen matched men as non- athlete subjects participated in this study. Trunk extensor muscle fatigue was produced by dynamometer. Stance postural sways were evaluated by force platform device in bipedal stance with open eye.

Results: In pre-fatigue state there is no significant difference between two groups. Fatigue had significantly effect on postural sways in both group after Lumbar muscle fatigue specially in non-athlete group (P ≥ 0.05) .

Conclusion: The postural control of athletes after muscle fatigue was better than non athlete subjects probably due to better proprioception in athlete subjects.

Keywords: Muscle fatigue, Postural control, Force plattform.

Background and Aim: Reliability or unreliability of the results achieved from recording of surface electromyography of muscles has always been questioned. The aim of present study was to  measure the reliability of the delayed reaction time of muscle electromyography of the knee joints on the exposure of unexpected rotary turbulence in the transverse plane from the area of supporting surface.

Materials and Methods: Twenty healthy women from 19 to 30 years old and free from any clear deformities in the lower extremities were participated in the present study. Surface electromyography of the six knee musculature was carried out for every subject separately in 4 situations including: External Rotation (Ext Rot) from plantar area on the transverse plane with bent and straight knee, Internal Rotation (Int. Rot) with the same conditions, Single Leg Stance situation in 4 stages, and repeatability of Intra Session through intra-class correlation coefficients when the muscles are in action on the exposure of turbulence in four applied forms were analyzed.

Result: The results from 24 analyzed forms showed that 18 forms of muscles at the time of action had moderate to high repeatability (Monroe Classification)

Conclusion: Regarding reliability, the muscles indicated different amounts in onset latency time, on the exposure of rotary turbulence, according to joint angle and the direction of applying rotation on the transverse plane. In respect to direction of rotation, most of the muscles indicated more reliability on the exposure of external rotation turbulence (clockwise) in relation to internal rotation (anti-clockwise) and also regarding the joint angle in turbulences with straight knee in relation to turbulences with bent knee. 

Keyword: Knee muscles, Surface electromyography, Reliability, Rotational turbulence

Background and Aim: The main cause of Myofascial pain syndrome is trigger point. The purpose of this study was to compare muscle energy technique (MET) with dry needling (DN) on latent trigger point of upper trapezius.

Materials and Methods: Fourty females, with diagnosis of latent trigger point of upper trapezius after adopting the inclusion and exclusion criteria were equally and randomly allocated into either the muscle energy technique or dry needling groups. Each patient received one treatment to the upper trapezius muscle. Outcome measures (visual analogue scale (VAS), pressure pain threshold (PPT), and range of active contra lateral flexion (CLF) measured before and 48 hours after treatment.

Results: Two techniques which used in this study were effective for treating latent trigger point of upper trapezius (P<0/001) but no significant differences were found between the two groups in terms of the above variables (p>0/05).

Conclusion: This study demonstrated that muscle energy technique was as effective as dry needling in improvement of VAS, PPT and ROM in subjects with latent trigger point of upper trapezius muscle. But since muscle energy technique is safe and non-invasive method, therefore, if you want to select one of these two techniques, muscle energy technique is recommended.

Keywords: Dry needling, Muscle energy technique, Trigger points

Background and Aim: Shoulder injury is one of the most common injuries in overhead sports. Impingement syndrome is most frequent cause of these injures. Scapular has important biomechanical role in normal shoulder function .Muscle imbalance changes normal scapular arthrokinematic and as a result the risk of injury is high. One of the treatment methods which is used in athletes with impingement syndrome is kinesio taping. Goals of this study was to investigate the effects of kinesio taping of trapezius muscles on pain , functional movements of shouhder joint and lateral scapular slide in athletes with impingement syndrome.

Materials and Methods: Fifteen athletes with a mean age of 30.53±3.56 with impingement syndrome participated in this study. Pain with visual analog scale , functional movements and lateral scapular slide test in 3 positions was  assessed . Then kinesio taping was used for trapezius muscles .Repeated evaluation was performed in 3 different periods of : 20 minutes , 72 hours , 6 days  after first session.

Results: Mean of  pain was reduced in 72 hours and 6 days after kinesio taping (p=0.003) .  Ext.rot + abd movement after kinesio taping was improved and the most improvement was 6 days after kinesio taping (p=0.004). Int.rot+add movement after kinesio taping was improved and the most improvement was 6 days after kinesio taping (p=0.001). Lateral scapular slide test in first position and second position improved significantly. In third position test did not change significantly after kinesiotaping.

Conclusion: Kinesio taping of trapezius muscles in athletes with impingement syndrome has effects on pain reduction, improvement of functional movement of shoulder and improvement of scapular kinematic. Therefore kinesio taping can be used as a treatment in athletes with impingement syndrome.

Keywords: Kinesio taping, Trapezius muscles, Impingement syndrome.

Background and Aim: Several studies have investigated the effects of angular velocity on mechanical and physiological variables such as joint net torque, muscle force and myoelectrical activity, but so far its effects on the control of the pattern of synergist muscle activation during isokinetic movements have not been studied. In this experiment, a computational method of identifying and analyzing muscle synergies were used which is based on the framework of the uncontrolled manifold hypothesis to determine the variability of muscle synergies following movement velocity alteration.

Materials and Methods: Twelve healthy females without any known neurological or motor disorders participated in the experiment. The participants were positioned on a Biodex dynamometer. They were asked to perform ten continuous knee extension and flexion motions with maximal strength at 45˚/s or 300˚/s. Electromyographic activity of the vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF) were recorded and variance within the UCM (VUCM) and orthogonal to the UCM (VORT) with respect to an appropriate Jacobian matrix was computed. An independent t-test was used to compare VUCM between two velocities.

Results: Across subjects, VUCM was significantly higher than VORT (VUCM>VORT) in both tasks. There was no significant difference in VUCM between two velocities (p>0.05).

Conclusion: Our findings suggest that angular velocity is not an important parameter when a controller of a multi-element system wants to stabilize a particular value of a performance variable.

Keywords: Variability, Angular velocity, Muscle synergie, Externsor muscle.

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