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The flexible-bar with a small amplitude of 5 Hz, which transmits vibrations to the trunk, enables the activation of the core muscles that can be used to rehabilitate subjects with low back pain. Two types of exercise direction that can affect trunk muscles of low back pain subjects similar control group are not known. This study aimed to evaluate and compare exercises with two directions of the oscillating flexible poles in people with and without low back pain (LBP).

Twelve women with Mean±SD age of 28.75±2.92 years, and body mass index (BMI) of 22.31±2.10 kg/m2 and a history of low back pain, and 12 healthy subjects with Mean±SD age of 28.75±2.49 years and BMI of 21.59±1.50 kg/m2 voluntarily participated in this study. The electromyography (EMG) signals of trunk muscles were measured during two handheld oscillating flexible bars in two directions. The root means square (RMS) of signals for each muscle is normalized by the maximum RMS.

The results of comparing two types of exercise in two groups showed significant differences for left external oblique (P=0.017), right external internal oblique (0.002), and left internal oblique (0.008). Also, the difference in the interaction between group×exercise was significant only for left internal oblique (P=0.026).

Muscle activity in the low back pain group appears different while performing exercises with a flexible-bar compared to the control group. This confirms motor control impairment in these populations and having different strategies for trunk co-activation during exercise.

Recently, the oscillatory bar has been proposed as a new and effective rehabilitation tool in people with nonspecific low back pain (NSLBP), although its effects on muscular control in this population have not been well documented, especially in lower extremity muscles and different support surface conditions. This study aimed to evaluate and compare the effects of flexi-bar use on stable and unstable surfaces on electromyographic activity of trunk and lower extremity muscles in healthy persons and those with NSLBP. 18 healthy men and 18 men with NSLBP participated in this cross-sectional study. The root mean square value of electromyographic activity was calculated in the trunk and lower extremity muscles during 4 different task conditions: quiet standing (QS) or flexi-bar use on a rigid or foam support surface. A repeated measures test was used for statistical analysis. The results showed that the amplitude activity of almost all muscles was significantly greater during flexi-bar use than in the QS condition (P<0.05). The rectus femoris, tibialis anterior, and gastrocnemius demands were significantly greater on the foam than the rigid surface (P<0.05).  This study showed that oscillatory forces caused by flexi-bar use can increase muscle activation in multiple segments (hip and ankle in addition to trunk muscles) that are crucial for postural stability. Furthermore, the foam surface appeared to target the rectus femoris in addition to the ankle muscles. Using a flexi-bar may be helpful in NSLBP rehabilitation, and exercising on a foam surface may enhance additive hip muscle activity in people with NSLBP.

Aerobic exercise has been shown to decrease the functional disorders related to multiple sclerosis (MS). Nevertheless, the effect of aerobic exercise training on the cytokines and neuroprotective mediators associated with the disease activity has remained relatively unknown.

The present research was conducted to evaluate the responses of the vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α) to single-bout and six-week aerobic exercise training in the patients with MS.

Totally, 20 subjects ((n = 10) patients with MS and (n = 10) controls) who were matched in terms of gender, weight, body mass, and age were included in the study. Participants received aerobic exercise training at approximately 60% of VO2max in 30-min sessions 3 times a week for six weeks. Serum concentrations of the VEGF and TNF-α were analyzed pre- and post-exercise training (in the first session and after 18 sessions of the study).

Serum concentration of the TNF-α decreased significantly after a single bout and 6-week aerobic exercise training (P = 0.002 and P = 0.005) in the intervention group. Serum concentration of the VEGF increased significantly only after exercise in the first and 18th sessions in the intervention group (P = 0.017 and P = 0.022).

Our results revealed that exercise may influence the VEGF regulation in patients with MS. Although, further research is needed to determine the effect of exercise on the immune variables in patients with MS.

With regard to unilateral pain in some patients with low back pain (LBP), it is advisable to evaluate asymmetrical thickness of lateral abdominal muscles. This study aimed to compare abdominal muscle thickness asymmetry in patients with non specific unilateral LBP during rest and practicing several stabilizing exercises with hollowing maneuver.
This research has a case-control design. Sixteen female subjects with left and right unilateral LBP and 8 healthy subjects participated in this study. Internal oblique, external oblique and transversus abdominal muscles thickness were evaluated by ultrasound imaging technique in both sides of the subjects’ bodies during rest and hollowing maneuver with 3 stabilizing exercises; bridging, four point kneeling and abdominal crunch.
According to the findings, abdominal muscle thickness asymmetry during exercises was more than resting position in two groups but it is not statistically significant. Also, no significant difference was seen between case and control groups regarding abdominal muscle thickness asymmetry.
Considering the appearance of asymmetry in healthy subjects, it seems that asymmetry in abdominal muscles cannot be interpreted as pathologic phenomena in LBP subjects.

Reconstruction surgery is one of the treatment methods after an anterior cruciate ligament (ACL) injury especially in athletes. Reconstructed ACL is associated with altered joint biomechanics, abnormal muscle strength, gait disorder and decreased athletic performance. Abnormal walking pattern has been shown to be one of the functional consequences of ACL reconstruction..
The aim of this study was to investigate the reliability of kinematic and spatiotemporal gait parameters after ACL reconstruction using Zebris ultrasound movement analysis system..
A sample of convenience including 20 healthy athletes and 20 athletes 4 to 6 months after ACL reconstruction participated. Subjects walked on a treadmill for one minute at preferred, high and low speeds and kinematic and spatio - temporal parameters including stride time, stride length, maximum knee flexion, maximum knee flexion velocity and maximum knee extension velocity are calculated..
In the patient group, relative reliability measures for almost all parameters were high at low (ICC: 0.7 - 0.97), preferred and high speeds (ICC: 0.75 - 0.97). This was also true for the control group, were reliability for all parameters was high at low, preferred (ICC: 0.74 - 0.99) and high (ICC: 0.83 - 0.99) speeds, except for stride time of the left leg which showed moderate reliability. Additionally, at high speed, all parameters revealed very high reliability..
Zebris movement analysis system is a highly reliable instrument for the measurement of gait parameters at different speeds in healthy athletes and those after ACL reconstruction surgery. This implies its use in the assessment and treatment process of gait deficits in such a clinically important population..

The comparison between Voluntary and automatic contraction of deep abdominal muscles in patients with Nonspecific Low Back Pain (nLBP) may justify being the best treat for them. The aim of this case-controlled study was to compare changes in the thickness of the Transverses Abdomin is (TrA) and Internal Oblique (IO) muscles during the Abdominal Drawing-In Maneuver (ADIM) and the Active Straight-Leg Raise (ASLR) test.
This study involved 30 women including 20 women with and 10 women without non-specific low back pain. The abdominal muscle thickness in the supine crook-lying, ASLR, and ADIM exercises were measured. Two-way repeated-measures ANOVA was used to compare the thickness ratio results between the two groups.
There were significant differences between the TrA (p These findings suggest that in both groups the deep abdominal muscles (the TrA and the IO) respond differently according to the variable type of activities such as voluntary or automatic, therefore, in training programs, in addition to a voluntary workout, automatic type of exercises should also be taught.

Several studies have demonstrated the postural control alterations in patients with low back pain. However, the difference in center of pressure (COP) parameters in the body sway in unstable conditions is relatively unknown in these patients. Therefore, the aim of the present study was to investigate the effects of unstable load and support surface on postural control in chronic low back pain (CLBP) patients.
CLBP patients (n=20) (mean age 31.30 years and mean BMI 25.20 kg/m2) and 20 healthy subjects (mean age 30.00 years and mean BMI 24.12 kg/m2) were asked to hold a load weighing 10 percent of their body weight while standing. Experimental conditions were manipulated based on stability of load (stable or unstable) and support surface (firm or foam). Using a force plate, COP sway parameters including sway amplitude (and its standard deviation) and sway velocity (and its standard deviation) in anteroposterior (AP) and mediolateral (ML) directions were measured.
Patients with CLBP exhibited less AP sway amplitude compared to control subjects (P=0.03). Furthermore, they had less ML sway velocity while holding the unstable load (P=0.05) and more ML sway amplitude while standing on foam (P=0.04).
In compare to healthy subjects, patients with CLBP demonstrated a different pattern of postural control during instability of load and support surface. In these conditions, altered proprioception and stiffening strategy can increase the risk of spine injuries.

Therapeutic exercises are regarded as one of most important therapeutic interventions for patients with chronic low back pain. Stabilization exercises are among the most practical ones for these patients. Effects of these exercises on psychological factors associated with pain and consequential functional disabilities are still remained unknown. The purpose of this study was to assess the effect of stabilization exercises on fear of pain, movement and disability in patients with low back pain. Twenty one patients with recurrent non-specific low back pain (14 in experimental, 7 in control group) were participated in this study. The scores for fear of pain, fear of movement and disability were recorded in the questionnaires. The experimental group performed isolated abdominal hollowing and bracing exercises in three sets of ten for each with two minutes rest between each repeat. Patients performed exercises with the use of pressure biofeedback and under the supervision of a physiotherapist in different positions including supine, sitting on a chair, standing still and standing with rapid arm raises with maximum acceleration once a day and for 20 sessions. The variables studied in this research were evaluated in both experimental and control groups after training sessions. Performing the stabilization exercises did not affect the fear-avoidance belief (P >0.05), while decreased the disability associated with back pain (P=0.01). This study showed that the psychological fears associated with pain in patients with recurrent non-specific low back pain, which also leads to continuity of back pain cannot be alleviated by performing stabilization exercises.

Lifting methods, including standing stance and techniques have wide effects on spine loading and stability. Previous studies explored lifting techniques in many biomechanical terms and documented changes in muscular and postural response of body as a function of techniques. However, the impact of standing stance and lifting technique on human musculoskeletal had not been investigated concurrently. A whole body musculoskeletal model of lifting had been built in order to evaluate standing stance impact on muscle activation patterns and spine loading during each distinctive lifting technique. Verified model had been used in different stances width during squat, stoop and semi-squat lifting for examining the effect of standing stance on each lifting technique. The model muscle''s activity was validated by experimental muscle EMGs resulting in Pearson''s coefficients of greater than 0.8. Results from analytical analyses show that the effect of stance width on biomechanical parameters consists in the lifting technique, depending on what kind of standing stance was used. Standing stance in each distinctive lifting technique exhibit positive and negative aspects and it can’t be recommended either one as being better in terms of biomechanical parameters.

Back muscles fatigue is one of the risk factors in workplace and throughout daily activities. Under fatigue conditions، loads will be redistributed among active and passive tissues in a non-optimal manner، where a single tissue may become overloaded and thus increasing the risk of injury with minimal loads. Because of the importance of abdominal muscles in producing and maintaining spinal stability in unstable conditions، it was necessary to investigate the response of these muscles in the presence of back muscles fatigue. Since it is not possible to study deep muscles with surface electromyography (EMG) techniques، in this study the function of abdominal muscles after lumbar extensor fatigue was investigated by ultrasound imaging technique.

Fifteen healthy women participated in this experimental study. Abdominal muscles thickness was measured from the lateral abdominal wall (Transverse abdomen (TrA)، Internal oblique abdomen (IO)، External oblique abdomen (EO)) using ultrasound imaging technique before and after the back extensor muscles fatigue protocol in upright standing with and without axial loading equal to 25% of the participants’ body weight. Repeated measure ANOVA was used to test the main effects of the load and back extensor muscle fatigue on the thickness of the abdominal muscles.

Although، symmetric axial loads equal to 25% of each participant weight had no significant effect on the thickness of abdominal muscles، back extensor muscles fatigue increased IO thickness significantly (P=0. 009).

The results showed that abdominal muscles response changes with back extensor muscles fatigue. By increasing the thickness of abdominal muscle، the stability of the spine could be maintained.

The collected electromyogram (EMG) signals from trunk musculature (e.g., rectus abdominis and external oblique muscle) are often contaminated with the heart muscle electrical activity (ECG). This paper introduces a novel method, the Empirical Mode Decomposition, for elimination of ECG contamination from EMG signals. The method is compared to a Butterworth high pass filtering. Results obtained from the analysis of generated and experimental EMG signals show that our method outperforms the high pass filtering for elimination of ECG contamination from trunk EMG signals.

Changes in load during asymmetric holding may be associated with particularly high risk of loss of balance and spinal injury. Therefore، in order to assess occupational lesions and to make preventive rehabilitation programs in such conditions like holding dynamic loads in asymmetric postures could be important.

In a cross-sectional study، COP amplitude and velocity sway were studied in 14 normal male volunteers during holding static and dynamic load in symmetric and asymmetric postures.

Similar Anterior-Posterior responses to the postures were seen، although asymmetric postures showed a larger Medial-Lateral COP amplitude and velocity sway (p<0. 05). While dynamic load increased Anterior-Posterior and Medial-Lateral postural parameters in asymmetric posture (p<0. 05)، we observed increase only in Anterior-Posterior direction in symmetric posture (p<0. 05).

The results showed that dynamic load challenges the postural stability control، with a higher effect in asymmetric posture.

Epidemiological studies showed that low back pain after load-carrying and holding is the most common disorder in industrialized countries and cause of dysfunction and economic problems. Variable dynamic loads impose varying moments about the intervertebral joints and cause a threat to balance. The aim of the present study was to compare the postural stability while holding dynamic load among subjects with and without nonspecific low back pain. In this semi-experimental study 24 men (12 healthy and 12 low back pain (participated. Subjects held static and dynamic loads in neutral and flexed trunk position (12 conditions). Center of pressure (COP) data were used to calculate: displacement, velocity and its standard deviation in Anterior- Posterior (AP) and Medial-Lateral (ML) directions, and path length. The results of repeated measurements and independent T- tests showed that displacement of COP in ML direction in low back pain patients (1.31, 1.22 cm) during holding dynamic loads (10-15 Hz) is more than healthy subjects (1.03, 1.10 cm). AP displacement, ML velocity and its standard deviation, path length, standard deviation of ML displacement in flexed and AP velocity in standing position during holding dynamic loads are more than static loads. The increased displacement of COP in subjects with low back pain during holding dynamic loads is probably due to higher sensory threshold in this patient. In addition, external perturbations in dynamic loads increase postural sway and may cause spinal injury.

This research was aimed at examining acute responses of hormones such as growth hormone (GH), total testosterone (TT), free testosterone (FT), free fatty acid (FFA) and cortisol to resistance (R), endurance (E) and endurance-resistance (ER) exercise.

The participants of this study were 10 healthy young men. R protocol included bench press, lateral pull down, leg extension and leg curl. E protocol comprised of 30 minutes pedaling by cycle ergometer at 70% maximum heart rate. In the ER protocol, the participants first went through the E protocol and after an interval of 15 minutes they performed the R protocol. In the control group they did not do any exercise. Blood samples were collected before, immediately after and 15 minutes after exercise.

Results indicated that GH and FT were significantly increased after all 3 protocols (P<0.05). TT and FFA were significantly increased after R and E protocols, respectively (P<0.05). Comparison between groups indicated a significant difference between GH and FT. Cortisol was significantly decreased in the E and ER protocols and the control group (P<0.05) but it did not have a significant decrease in the R protocol.

The E and ER protocols can increase GH with lower lactate and cortisol production, while the R protocol provides better anabolic environment for development and hypertrophy of muscle fiber because of higher stress, metabolic and hormonal responses. The increase of FFA after the E protocol was probably the cause of reduction of GH and TT secretion in the ER protocol.