Background and Aim: Neck pain is one of the most common musculoskeletal disorders in industrial society. There are complex changes in motor control of cervical spine in neck pain patients. The aim of this study was to compare the latency of activation of neck muscles during upper limb movement between neck pain patients and healthy subjects.

Materials and Methods: Eighteen chronic non-specific neck pain patients and eighteen healthy subjects who were matched in age, weight and height participated in this study. Subjects were standing on the ground and performed flexion and abduction movement of the right arm until at least 90 degree in five trials and consequently surface electromyography of neck muscles was recorded. Activation time of neck muscles was determined in comparison with the activation time of deltoid muscle (as an event) and then compared between two groups.  

Results: Findings of this study showed that in patients with chronic neck pain and healthy subjects during upper limb flexion and abduction movements, the superficial neck muscles were activated after deltoid activation. As well as in the neck pain patients compared to the healthy subjects superficial neck muscles onset was significantly appeared with delayed (P<0.05).

Conclusion: In patients with neck pain compared to healthy controls, the neck muscles were significantly delayed in responses to the internal perturbations of fast upper limb movements. It may be to increase the risk of injuries of neck region during fast upper limb movements.

Background and Aim: Since utilization of different patterns to perform voluntary movements influence human function, the aim of this study was to compare the selected kinematic parameters of active males in voluntary and involuntary gait initiation.

Materials and Methods: In this quazi-experimental study 13 young male subjects with age (23.3±3.1) years, height (1.75±.13) m, weight (68.9±7) kg and body mass index (22.4±1.8) k/m2, performed initiation of gait in 6 trials included three voluntary and three involuntary. Kinematic parameters measured by motion analysis system. K-S test was used to ensure the normal distribution of data and dependent T- test to compare within group variable at P0.05 level.

Result: The results showed that use of perturbation that leads to the initiation of motion, increased distance (p: 0.00) and velocity (p: 0.00) and reduced the time of gait initiation (p: 0.00), swing time (p: 0.00), stance time (p: 0.00) and double support time (p: 0.00), increased the amount of hip (p: 0.00) and knee flexion (p: 0.00) and decreased the amount of ankle dorsiflexion (p: 0.00). In addition, the displacement of the center of mass in the medio-lateral and vertical directions was decreased (p=0.03) and increased (p=0.01) respectively. Conclusion: The results indicate significant changes in most of the spatio-temporal parameters of gait initiation as a result of using Perturbation that leads to the initiation of motion. The results of this study can be recommended to be used in the field of gait initiation studies as well as in clinical cases to diagnose the normal and abnormality.

Abstract

Background and Aim: Patients with anterior cruciate ligament (ACL) deficiency are divided to coper and noncoper groups. The purpose of this study was to compare the efficacy of perturbation training with traditional rehabilitation on functional tests of lower extremity and knee muscles isokinetic peak torque ratio in two groups of patients with ACL-deficient: coper and noncoper

Materials and Methods: In this clinical trial study, 24 patients with ACL-deficient were divided to two groups: coper and noncoper. They participated in a management plan for 4 weeks, three times a week, including perturbation exercises and traditional rehabilitation (stretching, strengthening, and endurance exercises). Lower extremity functional tests through hop tests and knee muscles isokinetic peak torque ratio were evaluated.

 Results: After 4 weeks, all the functional tests improved significantly in both groups and timed 6-meter hop test showed significant improvement in coper group with respect to noncoper grouop (p< 0.05). There was no significant difference between two groups in knee flexors to extensors isokinetic peak torque ratio but this ratio was lower and close to normal values in coper group.

Conclusion: Perturbation training with traditional rehabilitation improves functional abilities of lower extremity in both groups of coper and noncoper of the patients with ACL-deficient. Probably, the patients of noncoper ACL-deficient have chance to return in some daily activities too.

Keywords: anterior cruciate ligament, perturbation training, functional tests, knee isokinetic peak torque

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: Anterior cruciate ligament (ACL) injury is common in sports competition and training. Following ACL rupture, neuromuscular system performance is disrupted. Perturbation training can improve the function of patients with ACL reconstruction. The aim of the present study was to assess the effects of perturbation training on ground reaction force and functional status of these patients .

Materials and Methods: Twenty patients with ACL reconstruction were randomly assigned into intervention (mean age: 24/2 ±3/4 years) and control (mean age: 27/1 ± 2/5 years) groups. The intervention group performed ten sessions perturbation training with rocker board, wobble board and Bosu. Peak vertical ground reaction force (GRF) and time to peak vertical GRF were recorded by KISTLER force plate during single leg landing from a 30cm height step. In addition, cross hop test also was evaluated as a functional test.

Results: Before perturbation training, both GRF and time to peak vertical GRF in reconstructed knee had not significant difference between two groups (P>0/05). In addition, functional test score had not significant difference between the groups (P=0/62). Following perturbation training, peak vertical GRF in reconstructed knee was greater than that in control groups (P<0/003).Although time to peak vertical GRF in reconstructed knee increased, there was not statistically significant difference between two groups (P=0/50). Furthermore, functional test score was statistically greater in intervention group (P=0/03).

Conclusion: This s tudy showed that perturbation training can improve functional status in patients with ACL reconstruction. In addition, force plate findings indicated that the patients tolerated more forces at longer time in single leg landing.

Key words: Perturbation training, Ground reaction force, ACL reconstruction, Function