صدیقه کهریزی

Osteoporosis is caused by a loss in the bone mass and the subsequent complications decrease quality of life (QOL) of the patients. This study is performed aiming to determine the effects of osteoporosis and thoracic kyphosis on the parameters of QOL in postmenopausal women.

This was a case-control study in which 53 postmenopausal women participated according to the T-score and thoracic kyphosis and were divided into four groups. Then, QOL and also different fields were compared among the groups using the 36-Item Short Form Health Survey questionnaire (SF-36). The data analysis was performed using SPSS software.

According to the results, the impact of osteoporosis on total scores of QOL was not significant (P = 0.783). In the areas of QOL, there was a significant difference only in the area of pain (P = 0.030). However, there was a significant difference regarding the effect of postural kyphosis on the total score of QOL (P = 0.021). In addition, in the fields of mental health problems, energy, mental feelings, and general health status, the differences were significant (P < 0.050).

Comparing the two factors affecting QOL in postmenopausal women (osteoporosis and postural kyphosis), it was revealed that the increased thoracic kyphosis had a more remarkable role in lowering the total score of QOL. Therefore, it is necessary to correct this situation in postmenopausal women. Keywords: Osteoporosis, Thoracic kyphosis, Quality of life, Postmenopausal women

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.

anterior cruciate ligament injury (ACL) has destructive effects on the postural stability and muscle strength of the knee and cause to impair the neuromuscular control. Patients with ACL injury divided to Coper and Noncoper groups. The purpose of this study has been to compare the muscle strength and postural stability of the two groups of the patients with the ACL- injury: Coper and Noncoper In this case control study, 23 athletic individuals with ACL rupture (11 coper, 12 noncoper) and 12 healthy athletic control ones, completely matched with case groups as demographic parameters, have participated. The Strength and postural stability have been evaluated. Postural control has been evaluated through the Biodex Stability System in two levels (4 & 8). The muscle strength has been evaluated by Isokinetic dynamometer and parameters are set at angular velocity of 60°/s and concentric form. Both groups of coper and noncoper of the patients with ACL injury have less postural stability compared to the control subjects, so that the Coper group have the greatest changes in the postural stability of the individuals(p<0.05). Also, the quadriceps muscle strength of the noncoper group is less than healthy group (p=0.00). The coper group with regarding the muscle strength and noncoper group with regarding the postural stability act so similar to the control subjects.

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.

Despite the widespread use of whole body vibration (WBV),especiallyin recent years, its neurophysiological mechanism is still unclear and the results about the facilitatory or inhibitory effects of WBV widely vary in different studies. The aim of this study was to compare between immediate (one session) and short term (12 sessions) effects of WBV on the spinal motor neurons excitability in healthy young men. Ten voluntary non-athlete healthy young-men (mean age:26.1±2.23) were participated in this study.In the sham sessions subjects stood on the turned off vibration plate while were maintaining the semi-squat position and then after 2 weeks wash-out, vibration training sessions were done on the same position with frequency of 30 HZ and peak to peak amplitude of 3 mm training sessions (sham & vibration) consisted of 12 sessions (3 sessions per week) and 4 set in each of them, weekly one set added to the training protocol. H reflex recruitment curve of soleus muscle was recorded before and after first and also 12th sessions in both sham and vibration training protocol. Ascending slope of recruitment curve, threshold and peak amplitudes and related intensities, amplitude of Mh and Hmax/Mmax ratio were determined. Immediate effects of vibration training 12th session caused a significant decrease of threshold amplitude and an increase of peak intensity (p=0.05 and p=0.05 respectively). Short term WBV training significantly decreased the threshold intensity of soleus recruitment curve (p=0.01). The results suggest the inhibitory effect of acute WBV training on the spinal motor neurons excitability. It seems that short term WBV training may be effective to facilitate the motor neurons excitability or increase the muscle spindle sensitivity.

The purpose of this study was to investigate shorts effects of two common stabilization exercises the Abdominal Hollowing (AH) and the Abdominal Bracing (AB) on abdominal and back muscle recruitment and behavior of lumbar curvature in static standing tasks.

In this crossover randomized clinical trial study (RCTs), 30 male (mean age 27/7) with NS-CLBP by convenience sampling were randomlly allocated to 3 equal size groups (2 interventions and one control group). Before and immediately after stabilization training (AH and AB), lumbar curvature and surface EMG activity from abdominal and back muscle was simultaneously recorded, in functional task that contain static standing with and without axial loading (12kg weight).

In static standing without axial loading, high EMG activity of local muscle was observed in the AH group and a significant reduction in erector spine (ES) and rectus abdominis (RA) activity in the AB groups. Meanwhile, in regards with axial loading, a reduction of TrA/IO in the AH groups and aslo ES with RA in the AB groups was seen (P<0.05).Lumbar curvature was surprisingly increased 2 degree after AH intervention and significantly decreased with axial loading (P<0.05).

Short effects of stabilization training with transferred to untrained tasks have ability to effect on curvature and sequentially on posture.

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.

Electromyography (EMG) response of muscles to Whole Body Vibration (WBV) has most studied acutely in areas close to the vibration platform. While، chronic effects of WBV on EMG response of muscles in far areas from vibration plate and with therapeutic perspective has been neglected. This study aimed to investigate the EMG response of muscles in areas far from vibration plate and important from orthopedic view in osteoporotic fractures and at risk population like women. Twelve nonathletic healthy young women (mean age ± SD; 25. 66 ± 2. 71 years) were participated in the one-blind controlled trial study design. They all enrolled to the WBV (static semi squat training + vibration) (vertical vibration، 30 Hz، 3mm) and placebo (static semi squat training) groups، randomly. Training protocol was similar in both groups except of WBV machine set as off in placebo group. EMG tests of muscles (lumbar erector spine (ES)، Gluteous maximus (G. max)، Rectus femoris (RF)) were carried out before and after twelve sessions of training and root mean square and median frequency were extracted for statistical analysis. WBV effects on RMS of ES (P = 0. 017) and G. max (P = 0. 014)، as well as median frequency of ES (P = 0. 020) increased than before training. The net effect of WBV compared with placebo increased statistically only in RMS of G. max muscle (P < 0. 001) and this increase was more than other two muscles، significantly (P = 0. 001). The results indicate the positive net effect of twelve sessions of WBV training on amplitude of muscle activity in G. max. This muscle is far from vibration plate and its strengthening can impose physiologic loading on the greater trochanter، cause likely to strengthen it and prevent osteoporotic fractures in this area. However، the relevance of this finding has to be further investigated in other studies and population like the postmenopausal women.

Aim of current study was to investigate the effect of changes of lumbar posture on postural balance in non specific choronic low back pain patients while applying axial load. In this experimental analytic study، 10 Non Specific Choronic Lo Back Pain NSCLBPwomen patients and 10 healthy volunteers that were matched together، evaluated. Postural sway of participants in neutral، lordotic and kyphotic posture of lumbar with and without axial load and with closed and opened eyes evaluated. Antro-posterior range، Antro-Posterior standard deviationMedio-Latral rangeand Medio-Latral standard deviation was evaluated in this study. Also for studying the patient’s avoidance belief and disability و three standard tools Fear-Avoidance Belief Questionnaire (FABQ)، Tampa Scale of Kinesiophobia (TSK) and Roland-Morris Questionnaire were used. Tha data were analyzed with Mix model ANOVA. Mix model ANOVA revealed in neutral posture AP rang (P=0. 045) and APsd (P= 0. 029) in LBP group، were significantly higher than healthy group. In LBP group AP range (p=0. 015) and APsd (p=0. 008) in kyphotic posture، were significantly lower than neutral posture and APsd (P=0. 046) in lordotic posture was higher than kyphotic posture. In LBP person’s fear of movement and pain also locating in end of range of lumbar posture. In kyphotic and lordotic posture were limitations for CNS and joints which control postural sway so persons with LBP limited their postural sway in these postures.

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.

The primary aim of the present study was to study the reliability of postural stability measures during whole body dynamic conditions، so they can be used in postural stability evaluations، investigations of injury mechanisms and assessments of treatment efficacy. Twelve healthy volunteers and 12 low back pain patients performed repeated trunk bending motions in eight different conditions of high and low speed، in symmetric and asymmetric planes and with or without external load. All measurements were repeated on a second session، 7-10 days later. Center of pressure (COP) data were used to calculate the standard deviation of amplitude and that of velocity in anterior-posterior and medial-lateral directions، the mean total velocity and the path length. Relative reliability was assessed using the intra class correlation coefficient (ICC) and absolute reliability using the standard error measurement، minimum detectable change and coefficient of variation. Results in both low back pain and healthy subjects revealed that the mean total velocity showed good to excellent reliability، with ICC ranging from 0. 6 to 0. 91. In the healthy group other parameters such as standard deviation of amplitude and standard deviation of velocity in the anterior-posterior direction showed good to excellent reliability (range: 0. 66-0. 97). In the low back pain group standard deviation of amplitude in the anterior-posterior direction in symmetric test conditions (range: 0. 61-0. 75) and standard deviation of amplitude in the medio-lateral direction in asymmetric test conditions (range: 0. 62-0. 81) were good or excellent. Mean total velocity is suggested as a good parameter for evaluation of postural stability in dynamic situations such as lifting and complex trunk movement and also for identifying low back pain patients from healthy subjects.

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.

Although the effects of whole body vibration (WBV) on the electromyographic (EMG) response of some muscles have been investigated in different studies، the effect of WBV on different types of motor units is not clear yet. The aim of the present study was to assess the different effects of a short-term WBV training on different motor units. Soleus (SOL) and gastrocnemius lateralis (GL) muscles were selected as the representatives of slow- and fast-twitch muscles، respectively. Twelve healthy young women (mean age 25. 66 ± 2. 71 years; mean height 161 ± 5. 6 cm; mean weight 66. 5 ± 5. 42 kg) were randomly allocated into the sham (n = 6) and WBV (n = 6) groups. The maximal isometric voluntary contraction (MIVC) of SOL and GL muscles was recorded before the initiation and after the termination of 12 training sessions. The training program was composed of the isometric squatting in both study groups such that in the sham group، the WBV machine set as off and in the WBV group، isometric squatting was offered in combination with whole body vibration (frequency of 30 Hz and peak to peak amplitude of 3 mm). The root mean square of EMG of soleous and gastrocnemius muscles was not statistically different between the two groups before training (P > 0. 05). The 12 sessions of training did not induce any statistically significant change in the muscle activity (EMGrms) of the SOL and GL muscles in either group (P > 0. 05). Although the RMS response of lateral gastrocnemius showed increasing behavior from the sham to the WBV groups، there was no significant difference in EMGrms values of these two groups (P > 0. 05). The difference value of EMGrms for soleus muscle did not also show any significant difference between these two groups (P > 0. 05). Despite the fact that EMGrms increases in soleus and gastrocnemius muscles were not statistically significant after WBV training، monitoring the response pattern in these two muscles between the sham and WBV groups is indicative of a positive effect of WBV on the lateral gastrocnemius motor units as a fast-twitch muscle.

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 study investigated the short-term effects of two stability exercises including Abdominal Hollowing and Abdominal bracing on stabilization parameters of Biodex Stability System in male subjects with non-specific recurrent low back pain. This Randomized Clinical Trial and case – control study was performed on 30 male subjects with non-specific recurrent low back pain by sample of convenience and randomly allocated to 3 control group (10 subject) and 2 experimental group (10 subject). Dynamic balance stability indices (Overall, Anterior–Posterior and Medial–Lateral) and Limit of Stability were measured by using Biodex Stability System before and immediately after exercise. All data by cross over, one way analyze of variance (one way ANOVA) and t-test was analyzed. Our finding showed that all indices except with Medial–Lateral were increased significantly in experimental group in comparison with control. In Abdominal Bracing group, both level of stability of 8 and 3, showed a significant reduction (P<0.05). Limit of Stability in both experimental groups with abdominal Hallowing (P= 0/001) and Abdominal Bracing (P= 0/01) increased significantly. The findings revealed that one session training affects increase balance due to muscle activity improvement.

Low back pain after load- holding and carrying can result in significant functional disability and financial disadvantage. Dynamic load-holding imposes varying torque on intervertebral joints and endangers the balance. The goal of the present study was to study the reliability of the postural stability during holding dynamic load for more accurate evaluation of lumbar spine injury.

Participants in this study were 12 healthy men and 12 male patients with low back pain (LBP), subjects were assessed 3 times in 8 conditions while they held dynamic loads in neutral and flexed trunk positions. Center of pressure (COP) data including displacement, velocity, path length and their respective standard deviations (SD) in anterior-posterior (AP) and medial-lateral (ML) directions were assessed. Relative reliability was measured using intra class correlation coefficient (ICC) while absolute reliability was obtained via standard error measurement (SEM) and minimal metrically detectable change (MMDC).

Healthy subjects’ velocity in ML direction (0.8-0.9), LBP patients’ velocity and its SD in AP direction (0.7-0.9) had the highest reliability among the parameters of interest. Reliability of displacement in ML direction and its respective SD yielded similar results in both groups (0.6-0.9). Reliability of displacement and its SD in ML direction and path length in healthy subjects were more than those of LBP patients.

Velocity of center of pressure in both AP and ML directions are suggested as appropriate parameters for evaluation postural stability during dynamic load- holding in subjects with and without non specific low back pain.

To investigate the effectiveness of a controlled accelerated short-term lumbar stabilizing exercises on postural indices and limit of stability in patients with non specific chronic low back pain. A sample of convenience of 20 patients with nonspecific chronic low back pain participates in this pretest – posttest study. Postural control indices including Overall stability index (OSI)، Anterior-posterior stability index (APSI)، Mediolateral stability index (MLSI)، time and functional performance of limit of stability were recorded before and after stability training. All data were analyzed using paired t-test. The results of this study showed significant difference all variables except OSI and APSI in double leg eyes open situation. As well، in single leg standing position OSI and APSI with eyes open were significant (p<0/05). Also، time and functional performance of limit of stability were significant before and after treatment. (p<0/001) Controlled accelerated short-term lumbar stabilizing exercises during 10 sessions may improve postural balance and limit of stability in males with non specific chronic low back pain.

To define the dynamic organization of the neuromuscular system, we need useful tools that allow for the expression of the neuromuscular system in low dimensional term (i.e one variable), so it seems that relative phase provides a better measure of organization of the neuromuscular system. Besides, selection of a measure for research or clinical use should be motivated by several factors, including the measure reliability. To our knowledge there seems to exist no study that have ever investigated the reliability of the relative phase and deviation phase in healthy or Low back pain subjects in dynamic movement tasks. Twelve healthy volunteers and 12 low back pain patients performed repeated trunk bending motion in eight different conditions of high and low speed, in symmetric and asymmetric planes, with or without external load. All measurements were repeated on a second session, 7-10 days later. Mean absolute relative phase and deviation phase of lumbar-thorax and pelvis-lumbar were used to calculate coordination pattern and variability. Relative reliability was assessed using intra class correlation coefficient (ICC) and absolute reliability was assessed using standard error measurement, minimum detectable change and coefficient of variation. Results in healthy subjects revealed that relative phase and deviation phase showed good to excellent reliability, with ICC range of 5.3-8.4 and in low back pain group ICC range was0 /52-0/85 except in three asymmetric test conditions and one symmetric test condition. SEM values range for healthy subjects were 0/92-4/8 and for low back patients were 1/2-5/8. Relative phase and deviation phase are suggested as good parameter to use for evaluating coordination and variability in dynamic situations such as lifting and complex trunk movement and also for discrimination low back pain patients from healthy subjects.

Lower extremity joint position sense (JPS) plays a significant role in the prevention of acute and chronic injuries and degenerative joint disease. It seems that subjects with patellofemoral pain syndrome (PFPS) have some impairments in knee JPS. The aim of this study was to evaluate the patellar taping effect on knee JPS in futsalist women suffering from PFPS. This study was conducted using a semi-experimental method and 30 female elite athletes (mean age=22 ± 2.37, year) participated in this research half of whom had PFPS. Electro goniometer instrument was used for the measurement of JPS. Absolute error of active angular reconstruction was calculated for 30 ◦ and 60 ◦. Finally, the data were analyzed with dependent paired t-test, based on the classification of participation into two groups, with and without PFPS and once based on having good (deviation from target angle ≥ 5 ◦, number=21) and poor (deviation from target angle < 5 ◦, number=9) JPS. The results showed that patellar taping cause JPS improvement in 30 ◦ for bo th groups with and without PFPS. However, according to the classification (participants in the two groups with poor and good JPS), the results showed that taping improved JPS in poor group (p=0.01), but taping in good group decreased JPS (0.04). Patellar taping can relatively develop knee JPS in futsalist women regardless of having PFPS; also in cases with poor JPS, it may be helpful and could improve knee JPS.

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.

The purpose of this study was to ivestigate of the postural strategies variability in low back pain patients, as a criterion in the adaptability evaluation of this system to the environmental demands and comparison of patients with healthy persons and also the importance of psychological factors associated with pain as an effective factor in postural disturbances was assessed.

This analytical, cross-sectional and case-control study was performed on twenty one recurrent non-specific low back pain patients whom had been selected simply and conveniently and twenty one healthy persons whom had been matched with patients. The electromyographic activity of Deltoid, External Oblique, Transverse Abdominis / Internal Oblique and Erector Spinae muscles of each person was recorded in 75 rapid arm flexion with maximum acceleration. To study the patient’s avoidance belief and disability, two standard tools; Fear-Avoidance Belief Questionnaire (FABQ) and Roland-Morris Questionnaire were used respectively. Data were analyzed by MANOVA and Pearson correlation coefficient.

The results showed that chronic low back pain patients exhibit less variability in their anticipatory postural adjustments than the control group(P=0.047). However, the decrease in variability of the timing of anticipatory postural adjustments of External Oblique(P=0.45) and Erector Spinae(P=0.6) muscles was not significant. The correlation between the timing variability of anticipatory postural adjustments and fear-avoidance belief questionnaire scores was significant(P=0.006), however there was no significant correlation between this variable and disability(P=0.09) in the patients.

There is a decrease in variability of postural control system of recurrent non-specific low back pain patients that can result in the persistence of pain and chronicity by decreasing the adaptability to environmental demands. The restoration of variability to postural control system should be taken into consideration in rehabilitation of these patients.

The theraputic exercise is regarded as one of the most important theraputic interventions in the chronic low back pain patients. Stabilization exercise is among the most significant practical ones in these patients. The study of the effects of these exercises on the variability of trunk muscles postural strategies and the ability in normalizing these strategies are among the uncertainties that have remained unknown up to the present time. The purpose of this research is the study of the effect of stabilization exercises on the variability of postural control strategies in these patients. The study was performed on 21 (14 males, 7 females) recurrent non-specific low back pain patients. The electromyographic activity of Deltoid, Transverse Abdominis/Internal Oblique, External Oblique and Erector Spinae muscles of each person was recorded in 75 rapid arm flexion with maximum acceleration. Then, 14 individuals were placed in the experimental group and 7 in the control group randomly.The experimental group performed isolated abdominal hollowing and bracing exercises using pressure biofeedback with 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, for 20 sessions. The variables studied in this research were evaluated in both experimental and control groups after the training sessions. The standard deviation of the trunk muscles onset latencies relative to deltoid muscle was statistically analyzed by a dependent t-test in both groups. The results revealed that performing the stabilization exercises increases the variability of the timing of anticipatory postural adjustments in TrA/IO in the experimental group (P=.037), while there were no significant changes in the variability of EO (P=.0346) and ES (P=.673) muscles in these patients. The variability of the timing of the anticipatory postural adjustment in TrA/IO (P=.199), EO (P=.702) and ES (P=.465) muscles did not show any significant changes in the control group. The study of the results showed that the reduction in the variability of postural control system in recurrent non-specific low back pain patients as a factor that causes the continuity of back pain can be improved by goal-directed stabilization exercises.

The purpose of this research was to compare dynamic balance in two groups of female futsal players with and without patellofemoral pain syndrome (PFPS). A comparative method was used in this research and the subjects included 30 genius female futsal players. 15 subjects suffered from PFPS with pain duration of 11.26±7.65 months and age of 21.73±1.83 years old, and 15 subjects who did not have PFPS with age of 21.46 ± 2.77 years old. Two groups had no significant differences in their height, weight and BMI (P>0.05). DPC (dynamic postural control) was measured by Biodex system at two instability levels of low (6) and high (3). DPC indices were total (TL), anteroposterior (APL) and mediolateral (MLL). Data were compared by independent t-test between the two groups. Results showed significant differences in all three DPC indexes at level (6) between groups (TL (P=0.03), APL (P=0.02), MLL (P=0.05)) so that the comparison of the means between the two groups revealed higher balance sway in PFPS group at level (6). But at level (3), in spite of higher mean of balance sway in PFPS group, no significant differences were observed between the two groups. This research showed some DPC disorders in female futsal players with PFPS and anterior knee pain. But this balance disorder depends on the amount of instability and DPC demands in different environmental conditions. In more stable conditions in which demands of postural control are closer to static conditions, balance reaction of PFPS group is lower than control group. But in more instable conditions which are closer to dynamic condition, balance reaction of PFPS group is more similar to the control group. Finally, it seems that more investigation is necessary to understand postural control reactions and to assess the relationship between anterior knee pain and DPC at other instability levels.