Background and Aim: Many studies investigated the effect of ankle-foot orthosis on reducing the incidence of sprain. In this study the influence of elastic and semirigid stirrup type orthosis on the onset latency of peroneus longus muscle activity as the most important support of ankle- foot region in response to sudden perturbation was assessed in healthy group and athletes with functional ankle instability.

Materials and Methods: Thirteen healthy female athletes and 10 female athletes with functional ankle instability (17 to 27 years old) were perturbed unexpectedly by a custom made ankle perturbation system in frontal plane under three conditions of without orthotics, using elastic orthosis, and using semirigid stirrup-type orthosis. Simultaneous recording of electrical activity of peronus longus muscle was performed with surface electromyography.

Results: The results showed the significant differences between muscular latency of injured and control groups without orthosis (P=0.018). The onset latency reduced using each type of the orthoses in injured group but it was not significant (P>0.05).

Conclusion: Although the latency time of peroneus longus muscle response delay didn’t show significant reduction using orthoses in injured group, it seems that using orthoses leads to proprioception improvement and sensiomotor control increasement by stimulation of cutaneous mechanoreceptors.

Key words: Functional ankle instability, Invertory perturbation, Electromyography, Orthosis

Background and Aim: An immaculate review of the literature reveals some changes on the vertical ground reaction force (VGRF) in ACL deficient knee subjects. However, the details are not clear yet. The current study aimed to study these changes in the ACL-deficient and apparently healthy knees of the coper and non-coper ACL-deficient knee subjects in comparison with the normal knees.

Materials and Methods: Sixteen unilateral ACL-torn subjects included 8 copers and 8 non-copers were recruited in this quasi-experimental study and were compared with 16 normal knee subjects (8 subjects matched to each coper and non-coper groups). All subjects walked barefoot and with their preferred speed in a 6-meter walkway and placed their wanted foot on the platform of a Zebris pedobarograph tool. The patients were asked to place their injured and healthy feet separately on the platform. The control group placed their foot matched to the ACL-deficient legs on the platform. The testes were repeated so much to have five acceptable trials. The outcome measures included the peak F1Z, F2Z, F3Z of the vertical ground reaction force values and the times to reach these peak values as well as total stance time of the tested feet.

Results: The results showed only a significant lower F₁Z value in the non-coper ACL-deficient knee subjects (p=0.008). No significant changes were shown in the F₂Z, F₃Z or the times reach to F₁Z, F₂Z and F₃Z values (p>0.05). The stance time of the coper ACL-deficient knee subjects increased significantly in the non-coper ACL-deficeint knee subjects when compared to the coper and healthy knees (p=0.005).

Conclusion: The reduced F1Z of the vertical ground reaction force at initial contact as well as increased total stance time seen only in non-coper ACL-deficient knee subjects reveals inadequate compensatory mechanism in these patients as a counter force stress at initial contact and weight bearing. However, the coper ACL-deficient knee subjects compensated these forces with good strategies and walked very similar to the control group.

Keywords: Vercial ground reaction force (VGRF), Time to peak vertical ground reaction force components, Coper & non-coper ACL-deficient knee subjects, Pedobarography.

Background and Aim : Chronic non-specific low back pain is one of the important health problem in military and different factors have been reported in its emergence. The aim of this study is to determine the association between low back pain and education level, Body Mass Index (BMI), exercise, smoking status ,work status and bad postures in military men.

Materials and Methods : In this non-experimental case-control study, 92 subjects (mean age= 29.16 year, SD= 8.55 year) with chronic non-specific low back pain and 93 subjects (mean age= 26.80 year, SD=9.22 year) without low back pain were selected by simple non-probability method from military centers in Tehran. Evaluation tools of this study included a self-administrated questionnaire, weighting scale and metal tape measure.

Results : According to the results of bivariate logistic regression, risk factors of exercise (P= 0.003), smoking status (P= 0.042), grade of BMI (P= 0.034), bad posture grades including heavy objects lifting movements (P= 0.007), bending movements (P= 0.003), rotating movements from the lumbar (P= 0.011), carrying bulky objects (P= 0.034), carrying heavy objects (P= 0.05) and working in squatting position (P= 0.005) had a significant association with low back pain. Job status (P= 0.999), education level (P= 0.056) and bad postures grades movements like wringing clothes (P= 0.958) had not a significant association with low back pain.

Conclusion : Doing regular exercise and having normal BMI decrease the risk of suffering from low back pain in the military while smoking and doing injurious physical activities during work (lifting heavy objects, bending movements and rotating from the lumbar, carrying bulky and heavy objects, and working in squatting position for a long time) increase the risk of suffering from low back pain.

Key Words : Chronic non-specific low back pain, Military forces, Biomechanical risk factors, Exercise

Background and Aim: One of the main causes of chronic non-specific low back pain is inappropriate working conditions, high repetition of one activity or work heaviness. An appropriate, accurate, inexpensive and easy assessment tools is necessary for measuring intensity of exposure to injurious  work activities, Identify individuals at risk and using appropriate treatment. The aim of this study is to compare the single-item Borg scale with JRPD scale to identify individuals at risk of exposure to injurious work activities in chronic non-specific LBP.

Materials and Methods: In this cross-sectional survey study, 92 subjects with non-specific low back pain by mean age of 29.16 (SD= ± 8.55) years and 93 healthy subjects by mean age of 26.80 (SD= ± 9.17) years and matched of work time, age and type of service with subjects with non-specific low back pain were selected by simple non-probability method. Single-item Borg scale and JRPD scale were used to assess the intensity of injurious work activities.

Results: Considering JRPD scale as a criterion scale, the sensitivity rate of 82% and specificity rate of 28% was obtained for single-item Borg scale at the moderate threshold. While the severe threshold for this scale, sensitivity and specificity rate were 25% and 85%, respectively. Also, the results showed that both single-item Borg scale and JRPD scale has significant ability to classify subjects with non-specific low back pain which are exposed or not exposed to injurious work ability (P<0.001). 

Conclusion: The single-item Borg scale has high sensitivity and low specificity at the moderate threshold and above and high specificity and low sensitivity at severe threshold to identify individuals Exposed to injurious work activities in military with chronic non-specific LBP.

Keywords: Injurious work activities, Non-specific LBP, Single-item Borg scale, JRPD scale