[Long-term effects of foot orthoseson leg muscles activity in individuals with pesplanus during walking]

Foot orthoses are widely prescribed to treat a range of lower extremity problems. Long-term biomechanical effects of foot orthosesare not clearly documented in the literature. The aim of this study was to examine long-term effects of foot orthoses on leg muscles activity in individuals with pesplanus during walking. In this clinical trial we selected 45 subjects after clinical examination. The subjects were divided into three equal groups: experimental pesplanus, control pesplanus and a healthy control group [with normal feet]. In the pre-test stage, electrical activity of leg muscles including tibialis anterior, peroneus longus, medial gastrocnemius and soleus were recorded at stance phase of walking, while all subjects walked barefoot along a 14m line. Experimental pesplanus group wore the custom-made orthoses for a period of six months. Then experimental pesplanus and control pesplanus groups underwent post-test. One-way ANOVA was used for data analysis. After six months of utilizing foot orthoses, the tibialis anterior activity significantly decreased in contact sub-phase [P=0.006]. The medial gastrocnemius activity showed a significant decrease in midstance sub-phase in the post-test [P=0.007]. Also, the soleus muscle had decreased activity in contact [P=0.033] and midstance [p=0.023] sub-phases in the post-test. According to the results of this study, we found that long term use of foot orthoses could change muscle activation and result in secondary adaptation

[Comparison of activation pattern of selected trunk muscles during over ground and treadmill walking]

Given the biomechanical differences between over ground and treadmill walking, it is expected that the contraction of muscles should be also different, so exercise training in these scenarios may have various effects on trunk muscles. The aim of this study was to compare amplitude and duration of activation of trunk muscles during over ground and treadmill walking to prescribe a suitable exercise mode considering the special circumstances of each person. Nineteen healthy 20-40 years old male with sedentary life style were selected via simple sampling. Surface electromyography of rectus abdominis, external oblique, longissimus and multifidus muscles were recorded. In each gait cycle, there was not statistically significant differences on duration of trunk muscles activity between treadmill and over ground walking. The mean amplitude of these muscles was greater on treadmill in comparison with over ground and this difference was statistically significant for rectus abdominis [P=0.005], longissimus [P=0.018] and multifidus [P=0.044] muscles. Stabilizing role of trunk muscles during walking causes them to be active throughout the entire gait cycle. The increased muscle amplitude on treadmill might show that more motor units may be recruited during the contraction, which is helpful in prescribing the appropriate type of exercise especially to patients who have trunk muscles weakness

[ effect of poron layered insole on ground reaction force in comparison with common insole on subjects with flexible flat foot]

Flexible flat foot is a congenital common deformity in lower extremity associated with ligamentus laxity. This deformity may cause hammer toe, heel spur, inflammation of achille tendon, early muscle fatigue during sport, foot imbalance and pain in leg, knee and hip. The use of insole with medial arch support considered as one of the common treatments for patients. The purpose of this study was to determine the effect of a composite insole, Ethy1 Viny1 Acetate [EVA] with Poron layer on ground reaction force on subjects with flexible flat foot in comparison with common EVA insole. Fifty two subjects [14 Male and 38 female] between 18-40 years of age with flexible flat foot participated in this study. Twenty six subjects received Poron insole [EVA with Poron layer] and 26 subjects received common EVA insole. After assessment each subject asked to walk with normal speed across two force plate in two conditions, walking with insole and shoe and walking without insole. Then each subject asked to use insole for forty hours during two weeks. Vertical ground reaction force in the first session and after two weeks was assessed. Impact force and first peak of vertical ground reaction force [F[1]] with Poron insole in comparison with shoe significantly increased in second session [P<0.05]. The second peak [F[3]] with common insole in comparison with shoe significantly increased in second session [P<0.05]. Significant reduction was noted in first peak [F1] with common insole in second session in comparison with first session [P<0.05]. There was no observable significant difference in two groups before and after intervention. The results of this preliminary study show that both insoles change vertical ground reaction force in comparison with shoe alone. But using a composite Poron Layer on EVA insole has not demonstrated a significant difference with common arch support insoles. Therefore application of Poron Silicon layer on EVA insole by itself can not show a significant reduction of ground reaction force

[Repeatability assessment of quantified measurement method in hand drawing skills]

Because of high incidence of hand injuries and the need for a quantitative method that provides measures of patient improvement in treatment period a precise and easy-to-apply quantitative procedure is necessary. As a first step in validating of such a method, the intersession repeatability of quantified measures was assessed in this study. Measurement of hand drawing skills by drawing circle shape in two speeds [preferred and maximum] and spiral shape just in a preferred voluntary speed with two repetitions for each subject was assessed in 15 subjects. Digital data was recorded by a Tablet PC using special software with average sampling rate of 120 Hz. The quantified variables computed for circle and spiral drawing tests with preferred speed were reliable [0.55 < ICC < 0.85], so they can be used for drawing quantifications. Results of drawing circles with maximum speed were not reliable [ICC < 0.5]. Repeatability analysis revealed that measures based on drawing circles with maximum speed are not repeatable and cannot be used for process monitoring. This may be due to large variation in providing maximum drawing speed during test time. On the other hand, spiral and circle drawing parameters with preferred speed had a better repeatability and can be used for quantification of hand drawings in researches

Trapezius muscle activity in using ordinary and economically designed dentistry chairs

Most dentists complain of musculoskeletal disorders which can be caused by prolonged static posture, lack of suitable rest and other physical and psychological problems, We evaluated a chair with a new ergonomic design which incorporated forward leaning chest and arm supports. The chair was evaluated in the laboratory during task simulation and EMG analysis on 12 students and subjectively assessed by 30 professional dentists using an 18-item questionnaire. EMG activity of right and left trapezius muscles for 12 male students with no musculoskeletal disorders was measured while simulating common tasks like working on the teeth of the lower jaw. Normalized EMG data showed significant reduction [p<0.05] in all EMG recordings of the trapezius muscle. Dentists also unanimously preferred the economically designed chair. Such economically designed chairs should be introduced as early as possible in student training before bad postural habits are acquired

Effect of movement direction variation in relation to gravity on generalized motor program recruitment in fast single joint elbow movements by use of surface electromyography

The precise control of arm kinematics and kinetics as well as interaction of the arm with the external word, is an essential condition to perform skillful motor actions. Gravity has significant effect on spatial orientation, proprioception, displacement, start and stop of hand movements. The purpose of this research was to study the effect of movement direction variation in relation to gravity on generalized motor program recruitment in fast single joint elbow movement by use of surface electromyography. Fifteen volunteer students [mean age 24.8 +/- 3.8 years] without sensory motor impairments participate in this study. Ninety percent of full range of motion at the elbow joint was used as goal degree. Subjects asked to do aimed elbow flexion as fast as possible in seven different direction in relation to gravity. While they were performing movements, surface electromyography was recorded from biceps and lateral head of triceps muscles. Relative timing, relative activity and sequence of contraction were derived from RMS. Data were analyzed by using repeated measure variance analysis. Muscle activation patterns were different in three positions from rest. There were significant difference between relative activity [p<0.001] and relative timing [p<0.003] in some positions. In fourth position, sequence of muscle contraction was different in seven subjects. It seems that change in movement direction in relation to gravity is one of effective parameters in movement planning and execution and it can recruit different generalized motor program

[Studying the effect of perturbation training on gait kinematics of patients with anterior cruciate ligament injury]

Anterior cruciate ligament [ACL] damage is the most common injury of knee. It can change gait kinematics. Neuromuscular training and perturbation treatment programs are supposed to be effective in modifying gait kinematics of patients with ACL damage. The purpose of this study was to determine the effect of modified perturbation training protocol on gait kinematics in ACL deficient patients. Ten professional male athletes, between 18 and 45 years, with at least 6 and at most 24 months history of unilateral ACL rupture were enrolled in the study. Kinematics data of hip, knee and ankle joints were recorded using electrogoniameter device during walking before and after ten sessions of perturbation training. IKDC Subjective and Lysholm questionnaires scores were analyzed before and after training. IKDC Subjective and Lysholm questionnaires scores significantly improved after treatment [P=0.005]. Hip range of motion [P=0.02], peak flexion of hip [P=0.02], hip angle at stance phase [P=0.02] and peak dorsiflexion of ankle [P=0.03] were significantly increased after training. Perturbation training probably affects neuromuscular control and modifies feed-forward control, thus it can improve compensatory patterns of ACL deficient patients during gait. ACL deficient patients may adapt their problem with further use of hip joint and increasing hip flexion

Reliability and minimal detectable change of foot arch height index device

This study was aimed to examine the reliability of a developed device measuring [arch height ratio] index. 40 feet [the right and left foot of 20 subjects] were measured. Foot length was measured from posterior aspect of calcaneus to the tip of longest toe and dorsum height was measured at the midpoint of total foot length. All measurements were assessed in three weight bearing conditions of 10, 50 and 90 percent of total body weight on three occasions [10 minutes and five days after the first measurement] by a single rater. Finally the arch height ratio index was calculated. The ICC values in different conditions of 10, 50 and 90 percent of total body weight in 10 minutes after the first measurement were calculated 0.96, 0.97 and 0.92 and in five days after the first measurement were calculated 0.97, 0.97 and 0.91. Minimal detectable change values of arch height ratio index in all conditions of measurement were 0.01. Simplicity of usage, low cost and high reliability of this device is highly recommended for clinical and research use

Comparison of electromyographic responses of superficial neck muscles in patients with chronic neck pain and healthy subjects during posterior - anterior perturbation

Several studies have reported significant disturbances in vertical posture during various standing and walking conditions, but there is little evidence about the behavior of related muscles in dynamic conditions such as external perturbation, so this study was done to investigate and to compare the delay in response of upper trapezius and sternocleidomastoid muscles as two superficial muscles in the neck area, in posterior-anterior perturbation among patients with chronic neck pain and healthy subjects. This study was a case-control study with simple nonprobable sampling. 32 subjects [16 healthy subjects and 16 patients with chronic neck pain] participated the study. Data collection was done using questionnaire and test performance. The equipments included dynamometer, chronometer and surface kinesiology electromyography. Dropping the weight equal to 10% of total body weight, performed using electrical magnet, followed by pulling of the trunk inducing perturbation was performed. There were significant statistical differences in response onset of upper trapezius [p=0.032] and sternocleidomastoid [p=0.012] muscles between two groups. This meant the response onset in patients was longer than healthy subjects. Pain can change the onset of response of trapezius and sternocleidomastoid muscles and possibly decrease muscle activity in deep muscles and change the pattern of muscle activation and possibly it can increase the risk of injury in patients with chronic neck pain

Effect of symmetry improvement in weight bearing on postural stability of hemiparetic patients

Impaired postural control has been known as the main cause of fall in hemiparesis after stroke. Asymmetry of weight bearing on lower limb is one of the prominent characteristics of postural imbalance in these patients. The aim of this study was to evaluate the effect of symmetry improvement in weight bearing through therapeutic interventions on postural stability in hemiparetic patients. In this quasi - experimental study which 27. hemiparetic patients were selected through sample of convenience by simple method from men and women who were referred to neurology clinic of Hazrat-e-Rasool hospital. For postural assessment patients stood quietly with open eyes and close eyes on force plates. Primary assessments included evaluation of asymmetry index [AI], RMS COP displacement [Root Mean Square of Center of Pressure] and RMS COP velocity in both frontal and sagital planes. Then a 10mm lift was inserted under the unaffected limb and primary assessments were repeated. Data were analyzed by repeated measure ANOVA test. Simple main effect of lift on asymmetry index was significant [P<0.0001]. There was no significant interaction between vision and lift. Simple main effect of lift on postural stability variables was also non significant [for RMS COP displacement in frontal and sagital planes P=0.186 and P=0.245, respectively and for RMS COP velocity P=0.259 and P=0.342 respectively]. Inserting a lift can improve symmetry by shifting center of gravity to midline. Since symmetry improvement did not decrease postural instability, asymmetric weight bearing can not be the primary cause of postural instability and may not be the principal target of rehabilitation programs aiming at restoring standing balance after stroke