An Examination of Limb Position for Measuring Toe-grip Strength

[Purpose] The purpose of the present study was to investigate the limb position at which the maximum toe-grip strength could be exerted as well as measurement reproducibility. [Subjects] Twenty healthy young women were selected. [Methods] We measured toe-grip strength under three conditions: 90° hip and knee flexion while sitting, 90° hip flexion and knee extension while sitting, and a standing position. [Results] We found that toe-grip strength was significantly lower in the 90° hip flexion and knee extension sitting position than in the 90° hip and knee flexion sitting position and standing position. Moreover, the 90° hip and knee flexion sitting position produced the best intraclass correlation coefficient (r = 0.813). [Conclusion] The results suggest that 90° hip and knee flexion while sitting is the most suitable limb position for measuring toe-grip strength, as this position allows maximum strength to be exerted and allows measurements to be repeated.Key words: Toe-gripping strength, Reproducibility, Healthy females     

Comparative Analysis of Acromiohumeral Distances According to the Locations of the Arms and Humeral Rotation

[Purpose] The purpose of this study was to compare the potential effects of resistance exercise according to the positions of the arms and the rotation of the humerus on the subhumeral acromial space. [Subjects] The study subjects were 34 subjects without shoulder pain. [Methods] Ultrasonographic measurements of the acromiohumeral distance of the subjects were made at three shoulder positions: 90° flexion, scaption at 90° abduction, and 90° abduction in an upright sitting position. The subjects were instructed to vertically push against a table to the maximum level with the humerus in internal, neutral, and external rotation. The measurements were made three times in each position. [Results] There was a significant difference in acromiohuneral distance between neutral and internal rotation of the humerus, and between external rotation and internal rotation of the humerus. In the scaption position, there was a significant difference between neutral and internal rotation of the humerus, and between external rotation and internal rotation of the humerus. In the 90° flexion position, there was a significant difference between neutral and internal rotation, and between neutral and external rotation. There was a significant difference between the flexion position and the abduction position, and between the flexion position and the scaption position. In terms of the internal rotation of the humerus, there was a significant difference between 90° flexion and 90° abduction. [Conclusion] These findings can be applied in exercises prescribed to increase the acromiohumeral distance and to aid the treatment and evaluation of shoulder dysfunctions.Key words: Ultrasonographic, Acromiohumeral distance, Humeral rotation     

Comparable effect of simulated side bending and side gliding positions on the direction and magnitude of lumbar disc hydration shift: in vivo MRI mechanistic study

Objectives:To investigate the direction and magnitude of mechanical influence to the lumbar disc in side bending and side gliding positions by considering shift of disc hydration.Methods:Twenty asymptomatic subjects completed this study. Direction of the hydration shift (θ), magnitude of the shift, and segmental lateral flexion and rotation angles from L1/L2 to L5/S1 during left side bend and side glide in lying were measured by magnetic resonance imaging (MRI) and compared using paired t-tests.Results:A significant difference (P<0.001) was detected in the segmental lateral flexion angle at L1/L2 between the side bending position (mean [SD], 5.1° [2.2°] left lateral flexion) and the side gliding position (mean [SD], 2.1° [2.7°] left lateral flexion). However, there was neither significant difference (P>0.05) in the lateral flexion angle at other segments nor rotation angles at each segment between the two lumbar positions. There was also no significant difference (P>0.05) in the θ value and magnitude of the hydration shift between the two lumbar positions. The disc hydration generally shifted to the right in the left side bending and side gliding positions at all disc levels.Discussion:This is the first study to investigate mechanical influence to each lumbar disc in the side gliding position using the shift of disc hydration on axial MRI. The comparability in the direction and magnitude of the hydration shift in the side bending and side gliding positions indicates that the maneuver of side gliding can produce comparable ipsilateral mechanical influence to each lumbar disc in comparison to side bending.     

Influence of testing position on lumbar isokinetic measurements]

The studies carried out on the lumbar spine, using an isokinetic type machine, showed the importance of the extensor muscles and the force they develop, compared with the flexor muscles. Both the sitting and standing positions were used without determining the better position. MAIN OBJECTIVE OF THE STUDY: To determine how the patients position influenced the performance of the muscles. We also studied a new parameter : the angle to maximal peak torque (APT). MATERIAL AND METHOD: 17 healthy subjects and 19 suffering from low back pain were chosen. We perform the test in both positions for each subject. We compare in each group the peak torque of the extensor and flexor muscles on both positions and the angle of this torque. RESULTS: Low back pain subjects flexor/extensor ratio were 1.71 sitting and 1.56 standing. Healthy subjects showed normal ratio of 0.69 and 0.84. CONCLUSION: The position of the subject has no influence on the results in the low back pain subjects, and the sitting position is preferred. The angle of development of the maximal peak torque in both groups of muscles was very interesting, especially in the subjects suffering from low back pain and shines a new light on the different functions of the muscles of the low back pain suffering subjects and the healthy subjects. This angle (APT) is inversed in low back pain subjects who develop more torque for the extensors in extension of the spine.     

Differences in lumbar and pelvic angles and gluteal pressure in different sitting postures

[Purpose] To investigate the effects of erect sitting, slouched posture with cross-legged sitting, and erect posture with cross-legged sitting on the lumbar and pelvic angles, and gluteal pressure. [Subjects] For the experiments, 17 healthy women were recruited. [Methods] All subjects were asked to perform three sitting postures: erect sitting, slouched posture with cross-legged sitting, and erect posture with cross-legged sitting. Lumbar and pelvic angles were measured using a three-dimensional motion-capture system, and gluteal pressure was measured using a pressure mat. [Results] Compared to erector sitting, slouched posture with cross-legged sitting showed significantly greater lumbar flexion, posterior pelvic tilt, and left pelvic tilt. Compared to erect sitting, erect posture with cross-legged sitting showed significantly greater lumbar flexion and posterior pelvic tilt. Compared to erect posture with cross-legged sitting, slouched posture with cross-legged sitting showed significantly greater lumbar flexion and posterior pelvic tilt. Compared to erect sitting and erect posture with cross-legged sitting, slouched posture with cross-legged sitting showed significantly greater left gluteal pressure; there was no significant difference in right gluteal pressure. [Conclusion] An erect posture can reduce changes in lumbar and pelvic angles, and gluteal pressure compared to a slouched posture during cross-legged sitting.Key words: Cross-legged sitting, Lumbar and pelvic angles, Gluteal pressure     

Immediate effects of dynamic sitting exercise on the lower back mobility of sedentary young adults

[Purpose] The aim of this study was to investigate the effects of dynamic sitting exercises during prolonged sitting on the lower back mobility of sedentary young adults. [Subjects and Methods] Seventy-one subjects aged between 18–25 years participated in this study. Following a randomized crossover study design, subjects were randomly assigned to two groups: sitting only and dynamic sitting exercise. The dynamic sitting exercise was a combination of lower back hyperextension and abdominal drawing-in movements which were repeated 6 times in a 1-minute period and performed every 20 minutes during a 2-hour sitting session. Lumbar range of movement was measured with the modified-modified Schober test, and the pain intensity was evaluated using the visual analog scale. [Results] After the experiment, the lumbar range of movement was significantly impaired in the sitting only group; however, it was significantly improved in the dynamic sitting exercise group. There were significant differences in lumbar range of movement of both flexion and extension between the groups. No significant difference in pain intensity between the groups was found. [Conclusion] These results suggest that dynamic sitting exercises during prolonged sitting can prevent decreases in lumbar range of movement in both back flexion and extension following a 2-hour sitting period.Key words: Back exercise, Flexibility, Long sitting     

Effect of the Shoulder Flexion Angle in the Sagittal Plane on the Muscle Activities of the Upper Extremities when Performing Push-up plus Exercises on an Unstable Surface

[Purpose] The purpose of this study was to investigate the effect of the shoulder flexion angle on the muscle activities of the upper extremities when performing the push-up plus exercise (PUPE) on an unstable surface with the forearm in the external rotation position. [Subjects] The subjects were conducted on 15 normal male adults. [Methods] A sling device was used for the unstable surface, and PUPE was performed with the forearm in the external rotation position. The shoulder flexion angles measured in the sagittal plane were 110°, 90°, and 70°. Electromyography was used for a comparitive analysis of the muscle activities of the serratus anterior (SA), the pectoralis major (PM), and the upper trapezius (UT). [Results] In the intra-group comparison, the muscle activity of SA was statistically the highest when the shoulder-flexion angle was 110°. [Conclusion] performing PUPE on an unstable surface, the muscle activity of the SA is activated the most when the shoulder flexion angle is 110° and the forearm is in the external rotation position.     

Comparison of lumbar spinal angle between normal body mass index and overweight young adults

[Purpose] This study compared the upper and lower lumbar angles of normal body mass index and overweight young adults, and examined the relationships among body mass index, waist circumferences, and lumbar angles. [Subjects and Methods] Sixty participants aged 18–25 years were recruited and allocated to 2 groups (n=30 per group): normal body mass index (18.5–24.9 kg/m²) and overweight group (body mass index, ≥ 25.0 kg/m²). During lumbar angle measurement, the participants stood in a relaxed position with bare feet. The upper and lower lumbar angles of each participant were measured using a flexible ruler, and the angle calculated by the tangent method. The waist circumference was also measured. [Results] The mean lower lumbar angle in the overweight group was significantly greater than that of the normal body weight group. Moreover, only the lower lumbar angle was associated with a significant increase in the body mass index (r=0.28). Waist circumference showed no association with the lumbar angles. [Conclusion] This is the first study to suggest that increased body weight could cause lower lumbar angle deviation in young adults. Further studies should investigate individuals with symptomatic back pain or back dysfunction and the impact of body weight on lumbar spinal angles.Key words: Upper lumbar angle, Lower lumbar angle, Overweight     

The Effect of Ground Tilt on the Lower Extremity Muscle Activity of Stroke Patients Performing Squat Exercises

[Purpose] The purpose of this study was to determine the effect of ground tilt on the lower extremity muscle activity of stroke patients performing squat exercises. [Subjects] Fifteen hemiparetic patients volunteered to participate in this study. [Methods] The subjects performed squat exercises at three different ground tilt angles: 15° plantar flexion, a neutral position, and 15° dorsiflexion. A surface electromyogram (sEMG) was used to record the electromyographic activities of the leg extensor muscle in the vastus lateralis (VL), vastus medialis (VM), gastrocnemius lateralis (GL), and gastrocnemius medialis (GM). The sEMG activity was analyzed using a one-way repeated measures ANOVA and a post hoc Bonferroni correction. [Results] The results of this study are summarized as follows. Significant differences were noted for the VL and the GL when the angle of the ankle joint was between the 15° plantar flexion and neutral positions during squat exercises involving the VL and when the angle of the ankle joint was between the neutral position and 15° dorsiflexion during squat exercises involving the VM. [Conclusion] In this study, sEMG showed that the VL and GL changed significantly during squat exercises according to the ground tilt angle of hemiparetic patients. Therefore, squat exercises with different ground tilt angles can be used to improve VL and GL strength.Key words: Electromyogram, Hemiplegic patient, Squat exercises     

Comparison of the Forward Head Angle and the Lumbar Flexion and Rotation Angles of Computer Workers Using Routine and Individually Fixed Computer Workstations

[Purpose] This study compared the forward head angle and the lumbar flexion and rotation angles of computer workers using routine and fixed computer workstations. [Subjects] Ten male workers voluntarily consented to participate in the study. [Methods] A 3-D motion analysis system was used to measure the angles of the forward head and lumbar flexion. All subjects performed computer work for 30 minutes using both types of workstation. [Results] When working at the fixed workstation, the forward head angle was less than that observed when the routine workstation was used. At the fixed workstation, the lumbar flexion and rotation angles were less than that at the routine workstation. [Conclusion] The computer workstation individually fixed for standard posture may have prevented poor sitting posture.Key words: Computer workstation, Forward head angle, Sitting posture     

Muscle activities of the rectus abdominis and rectus femoris and their ratio during leg raises performed by healthy adults

[Purpose] The purpose of this study was to analyze muscle activation during hip flexion in the supine position to examine the activation characteristics of the rectus abdominis and rectus femoris. [Subjects] The subjects of this study were 20 healthy adults (10 males and 10 females). [Methods] Muscle activities of the rectus abdominis and rectus femoris while raising the leg from 0°–60° were measured in 15-degree divisions and their ratio was calculated. [Results] Statistically significant differences were found in the muscle activities of the rectus femoris and rectus abdominis were found among each division of during hip flexion in the supine position. The rectus abdominis and rectus femoris ratios increased as the angle of hip flexion increased. [Conclusion] During hip flexion from 0°–45° in the supine position, femur motion caused hip flexion. At angles greater than or equal to 45° hip flexion was accompanied by pelvic motion.Key words: Hip flexion, Leg raise, Muscle activities     

How Different Knee Flexion Angles Influence the Hip Extensor in the Prone Position

[Purpose] The present study examined the effects of knee flexion angle on hip extensor muscle activity. [Subjects and Methods] Twenty healthy subjects maintained knee flexion angles of 0°, 30°, 60°, 90° and 110° in the prone position and performed maximal voluntary contraction in hip extension. Maximum torque in hip extension at the different angles was measured, and surface electromyogram activities of the gluteus maximus (GM), biceps femoris (BF) and semitendinosus (ST) were recorded and normalized by the maximum voluntary isometric contraction (MVIC). [Results] The maximum torque of the hip extensor showed significant decreases between 0°and 60°, 90° and 110° of knee flexion. The muscle activity of BF was significantly high at 0°, and GM showed a significantly higher activity than both BF and ST at 60°, 90°and 110° of knee flexion. [Conclusion] The maximum torque in hip extension and muscle activities of BF and ST were significantly high at 0° but they decreased at knee flexion angles of more than 60°. Therefore, we consider that more than 60° of knee joint flexion is required to increase GM activity, and to reduce the muscle activities of BF and ST.Key words: Gluteus maximus, Hamstring muscle, Prone hip extension     

The Effects of Elbow Joint Angle Change on the Elbow Flexor Muscle Activation in Pulley with Weight Exercise

[Purpose] This research investigated the effect of angular variation of flexion of the elbow joint on the muscle activation of elbow flexor muscles. [Subjects] The research subjects were 24 male college students with a dominant right hand who had no surgical or neurological disorders and gave their prior written consent to participation with full knowledge of the method and purpose of this study. [Methods] The subjects'' shoulder joints stayed in the resting position, and the elbow joint was positioned at angles of 55°, 70°, and 90°. The angle between the pulley with weights and forearm stayed at 90°. Surface electromyography was used to measure muscle activities. Three measurements were made at each elbow angle, and every time the angle changed, two minutes rest was given. [Result] The muscle activities of the elbow flexors showed significant changes with change in the elbow joint angle, except for the biceps brachii activities between the angles of 55° and 70° of elbow flexion. The muscle activities of the biceps brachii and brachioradialis showed angle-related changes in the order of 55°, which showed the biggest value, followed by 70° and 90°. [Conclusion] In order to improve muscle strength of the elbow flexor using a pulley system, it seems more effective to have a 90° angle between the pulley with weights and the forearm when the muscle is stretched to a length 20% greater than its resting position.Key words: Pulley with weight exercise, Joint angle, Muscle activation     

The effect of thoracic spine mobilization and stabilization exercise on the muscular strength and flexibility of the trunk of chronic low back pain patients

[Purpose] To investigate whether thoracic spine mobilization added to stabilization exercises increases the muscular strength and range of motion of the thoracic vertebrae of chronic low-back pain patients. [Subjects] This study enrolled 20 patients with chronic low back pain, who were divided into two groups. Ten subjects were randomly selected for the stabilization exercise group and the remaining 10 subjects received thoracic spine mobilization in addition to performing the stabilization exercises. [Methods] The patients performed stabilization exercises and received thoracic spine mobilization for 12 weeks. The range of motion and isometric muscular strength of the vertebrae of all subjects were measured before and after the intervention. [Results] In the comparison of muscular strength before and after the intervention, the change in muscular strength of the trunk flexors in the stabilization exercise group was 16.0±7.4 Nm, and that of the thoracic spine mobilization group was 34.2±7.6 Nm, a significant difference in each group. In the post-intervention intergroup comparison, the muscular strength of trunk flexors in the stabilization exercise group was 111.1±16.9 Nm, while that of the thoracic spine mobilization group was 125.9±11.3 Nm, a significant difference. Also, the muscular strength of the trunk extensors in the stabilization exercise group was 148.9±31.8 Nm, while that of the thoracic spine mobilization group was 182.9±37.2 Nm, a significant difference. The thoracic spine flexion in the stabilization exercise group was 29.8±9 degrees, while that of the thoracic spine mobilization group was 38.7±6.9 degrees, a significant difference. However, there was no significant difference in lumbar flexion values between the two groups. [Conclusion] Thoracic spine mobilization added to a stabilization exercise increased the muscular strength of patients with chronic low back pain.Key words: Isometric muscle strength, Lumbar stabilization exercise, Thoracic spine mobilization exercise     

Effect of the cervical flexion angle during smart phone use on muscle fatigue of the cervical erector spinae and upper trapezius

[Purpose] The purpose of this study was to examine the influence of the cervical flexion angle when using a smart phone on muscle fatigue of the cervical erector spinae (CES) and upper trapezius (UT). [Subjects] This study recruited 12 healthy adults. [Methods] Each subject sat on a chair, with his/her back against the wall and held a smart phone with both hands. Fatigue of the neck and shoulder muscles at different cervical flexion angles (0°, 30°, and 50°) was measured by electromyography. The following muscles were assessed: the right upper trapezius (RtUT), left upper trapezius (LtUT), right cervical erector spinae (RtCES), and left cervical erector spinae (LtCES). A cervical range of motion instrument was attached to the subjects’ heads to measure the cervical angle during the experiment. [Results] The RtUT and LtUT showed the highest muscle fatigue at a cervical flexion angle of 50° and the lowest fatigue at an angle of 30°. There was no significant difference in the muscle fatigue of the RtCES and LtCES at any of the cervical flexion angles. [Conclusion] UT muscle fatigue depends on the cervical flexion angle when using a smart phone.Key words: Smart phone, Muscle fatigue, Cervical flexion angle     

Kinematic analysis of the lower cervical spine in the protracted and retracted neck flexion positions

[Purpose] The aim of this study was to analyze lower cervical spine kinematics in protracted and retracted neck flexion positions in healthy people. [Subjects and Methods] The craniovertebral angle (CVA) and intervertebral body angles of the lower cervical spine of 10 healthy individuals were analyzed using fluoroscopy in a neutral sitting with the head in the neutral (N), protracted (Pro), and retracted (Ret) positions and with the neck in full flexion with the head in the neutral (N-fx), protracted (Pro-fx), and retracted (Ret-fx) positions. [Results] There were significant differences in the CVA and intervertebral body angle at the C3–4 level, and the Ret position showed the highest values followed by the N and Pro positions. Regarding the intervertebral body angle at the C4–5 level, the Pro position showed a higher value than the N and Ret positions. At the C6–7 level, the Pro position showed the lowest value compared with the N and Ret positions. In the CVA, the Ret-fx position showed a higher value than the N-fx and Ret-fx positions. [Conclusion] The results suggest that in the neutral sitting position, protraction is an ineffective posture due to overstress of the C6–7 segment, which is placed in a hyperflexed position at this level. Instead, retraction is the recommend posture for the patient with C6–7 degeneration, which makes for a more flexed position in the upper cervical spine and a less flexed position in the lower cervical spine.Key words: Head posture, Intervertebral body angle, Lower cervical spine     

A Sloped Seat Wedge Can Change the Kinematics of the Lumbar Spine of Seated Workers with Limited Hip Flexion

[Purpose] The purpose of this study was to determine whether a wedge type seat decreases the lumbar flexion angle of seated workers with limited hip flexion. [Subjects] Twelve sedentary workers with limited hip flexion were recruited. [Methods] Three seat surfaces were used: a level surface, a forward-inclining wedge, and a backward-reclining wedge. The angles of lumbar flexion and pelvic tilt were measured using a three-dimensional motion analysis system. Differences in kinematic data of the subjects seated on the three seat surfaces were analyzed using repeated one-way analysis of variance. [Results] The degree of lumbar flexion decreased significantly when using the forward-inclining wedge compared with the level surface and backward-reclining wedge. [Conclusion] These findings suggest that sitting on a forward-inclining wedge may be useful for minimizing the compensatory lumbar flexion of individuals with limited hip flexion who work in a seated position.Key words: Kinematics, Limited hip flexion, Seat wedge     

The Effects of Knee Joint and Hip Abduction Angles on the Activation of Cervical and Abdominal Muscles during Bridging Exercises

[Purpose] The purpose of this study was to examine the effects of the flexion angle of the knee joint and the abduction angle of the hip joint on the activation of the cervical region and abdominal muscles. [Subjects] A total of 42 subjects were enrolled 9 males and 33 females. [Methods] The bridging exercise in this study was one form of exercise with a knee joint flexion angle of 90°. Based on this, a bridging exercise was conducted at the postures of abduction of the lower extremities at 0, 5, 10, and 15°. [Result] The changes in the knee joint angle and the hip abduction angle exhibited statistically significant effects on the cervical erector spinae, adductor magnus, and gluteus medius muscles. The abduction angles did not result in statistically significant effects on the upper trapezium, erector spinae, external oblique, and rectus abdominis muscles. However, in relation to the knee joint angles, during the bridging exercise, statistically significant results were exhibited. [Conclusion] When patients with both cervical and back pain do a bridging exercise, widening the knee joint angle would reduce cervical and shoulder muscle activity through minimal levels of abduction, permitting trunk muscle strengthening with reduced cervical muscle activity. This method would be helpful for strengthening trunk muscles in a selective manner.Key words: Bridging exercise, Knee and hip joint angle, Muscle activation     

Measuring seated hip extensor strength using a handheld dynamometer: an examination of the reliability and validity of the protocol

[Purpose] The purpose of this study was to examine the reliability and validity of measurements of hip extensor muscle strength using a handheld dynamometer (HHD) with subjects in a sitting position. In doing so, we also aimed to establish a modified method of measurement for patients with flexion contractures in the trunk and lower extremities. [Subjects and Methods] In 20 healthy males, hip extensor muscle strength was measured using a handheld dynamometer in sitting, prone, and standing positions by contracting the hip extensor muscle isometrically with the knee flexed at 90 degrees. For each position, we investigated the relative and absolute reliability and validity of the measurements, and compared muscle strength between the different positions. [Results] The reliability and validity of measurements were highest in the sitting position and higher in both the sitting and standing positions as compared with those in the prone position. [Conclusion] Our findings suggest that measurements taken in a sitting position are accurate in assessing hip extensor muscle strength and would be applicable to patients with flexion contractures in the trunk and lower extremities.Key words: Hip extensor strength, Reliability, Bland-Altman analysis     

Effects of lumbar stabilization exercise on functional disability and lumbar lordosis angle in patients with chronic low back pain

[Purpose] This study examined the effects of lumbar stabilization exercises on the functional disability and lumbar lordosis angles in patients with chronic low back pain. [Subjects] The subjects were 30 patients with chronic low back pain divided into a lumbar stabilization exercise group (n = 15) and a conservative treatment group (n = 15). [Methods] The lumbar stabilization exercise and conservative treatment groups performed an exercise program and conservative physical treatment, respectively. Both programs were performed 3 times a week for 6 weeks. The degree of functional disability was assessed by the Oswestry disability index, and lumbar lordosis angles were measured by plain radiography. [Results] The Oswestry disability index decreased significantly in the both groups; however, it was significantly lower in the lumbar stabilization exercise group. The lumbar lordosis angle increased significantly in the lumbar stabilization exercise group after treatment and was also significantly greater than that in the conservative treatment group. [Conclusion] Lumbar stabilization exercise is more effective than conservative treatment for improving functional disability and lumbar lordosis angles.Key words: Lumbar stabilization exercise, Lumbar lordosis angle, Chronic low back pain