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: Proprioception is a component of somatosensory system. One of the most important somatosensory receptors is muscle spindles. Neck area with high density of muscle spindle, plays a significant role in providing this sense. With repeated contact sports, with high trauma on head and neck region, it is likely that proprioception will be impaired. The present study was conducted to compare proprioception between wrestlers, taekwondo players and non-athlete subjects to determine the effect of trauma on proprioception of craniocervical region.

Material and Methods: This study was a case-control study of 75 male with the age range of 18-30 years (Including: 25 professional wrestlers, 25 professional taekwondo players and 25 non-athlete subjects). Participants were selected through simple non-probability sampling. To assess proprioception of craniocervical region, angular repositioning of two positions (neutral and 50% of range of motion) was evaluated by using the cervical range of motion device (CROM device). The statistical method which used in this study was one way ANOVA.

Results: Accuracy of target repositioning (50% of range of motion) of extension, right and left rotation were significantly different between three groups (p<0.05). Returning to neutral position from mentioned movement was associated with a significant error (p<0.05).

Conclusion: It is assumed that proprioception of craniocervical region has been affected by trauma in wrestlers and taekwondo players, so that the accuracy of head repositioning for both neutral and target positions were reduced in wrestlers. However, taekwondo players had more errors in repositioning of target angle.

Keywords: Proprioception, Repositioning error, Craniocervical, Wrestlers, Taekwondo players

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

Background and Aim: ACL injury is one of the most common sport injuries which undergo reconstructive surgery. Electromyography or recording of muscles’ electrical activity is a suitable means to assess changes in motor control system output. The goal of this study is to compare the lower limb muscles EMG activity during drop landing in individuals after ACL reconstruction and healthy subjects.

Materials and Methods: Eleven men who had undergone ACL reconstruction 6 to 24 months ago (Age 29±6 years old) and 11 healthy men (Age 28±2 years old) participated in the study. Amount of electrical activity for tibialis anterior, vastus medialis, vastus lateralis, semitendinosus and biceps femoris muscles was recorded using surface electrodes during drop landing and calculated for two time intervals. The amount of activity was measured in -150 to +50 and +50 to +180 intervals in relation to the landing moment. Subjective IKDC questionnaire and cross-over hop functional test were used to determine the subjective and objective functional level.  Independent t test was used to determine between-group statistical differences.

Results: Feed forward activity of semitendinosus (P=.041) and biceps femoris (P=.008) muscles were significantly higher in ACLR group and feedback activity of vastus medialis (P=.03) muscles was significantly lower in ACLR group. Healthy individuals showed higher score on both the functional test and IKDC questionnaire. (P<.0005)

Conclusion: Individuals who had undergone reconstructive surgery of ACL showed different muscular activity compared to healthy subjects and closer to ACL deficient individuals 6 months after surgery and routine rehabilitation.

Keywords: Anterior cruciate ligament reconstruction, Electromyography, Neuromuscular control

Background and Aim: Forward Head Posture (FHP) is one of the most common postural disorders which related to current life style. This disorder may cause some changes in motor control of cervical muscles.

Materials and Methods: Eight subjects with Forward Head Posture and 8 matched healthy subjects wereParticipated. The kinematic and electromyographic activity of each subject was analyzed and the flexion- Relaxation phenomenon was determined.

Results: The results showed that the cessation of flexion-relaxation phenomenon was different between two groups (P<0.05). The result of Pearson correlation showed a significant positive correlation between Cranio-vertebral angle and cessation of the phenomenon (P<0.05).

Conclusion: The flexion- relaxation phenomenon was different in Forward Head Posture related to the healthy subjects and the concentric contraction was started with delay in the Forward Head Posture subjects. Therefore, the motor control and balance disorder may be seen in these subjects.

Keywords: Forward Head Posture, Flexion- Relaxation, Electromyography, Kinematic