Forward Bending Position Research Articles

Position-dependent trunk asymmetry assessed with scoliometer

Materials and methods The study comprised 996 girls, aged 9 to 13, mean 11.0 ± 1.0 years of age. ATI measurements were performed at three levels of the spine: proximal thoracic, main thoracic and thoracolumbar/lumbar. Maximal ATI values for standing and sitting forward bending positions were noted. Based on the ‘7°’ criterion, the number of children who need follow up was revealed, according to position: (a) standing, (b) sitting, (c) any of standing or sitting, (d) either standing or sitting.

2P1-E03 足指の動きを取り入れた人型サイズロボットの姿勢制御(ものづくり教育・メカトロニクスで遊ぶ(2))

This is basic research on the attitude control of a human size robot which walks treading by toes. The purpose of this research is to perform more stable attitude control so that the robot cannot fall down treading by toes like a human. The human can keep a deep forward-bent posture by using toes. Thus we focus on toes as one of control methods of preventing the robot from falling down. As a method of attitude control, we used "ZMP". It is the most popular method of attitude control. The model we assume is about 110cm tall and weighs 2kg. The experiments on two patterns, "using toes" and "not using toes" were conducted, and the results between them were verified.

G150035 足指の動きを取り入れた人型サイズロボットの姿勢制御

This is basic research on the attitude control of a human size robot which walks treading by toes. The purpose of this research is to perform more stable attitude control so that the robot cannot fall down treading by toes like a human. The human can keep a deep forward-bent posture by using toes. Thus we focus on toes as one of control methods of preventing the robot from falling down. As a method of attitude control, we used "ZMP". It is the most popular method of attitude control. The model we assume is about 110cm tall and weighs 2kg. The experiments on two patterns, "using toes" and "not using toes" were conducted, and the results between them were verified.

Rib Hump in Adolescent Idiopathic Scoliosis - Assessment of Its Flexibility and the Need for Thoracoplasty

We described a technique of measuring the flexibility of the rib prominence clinically before surgery, and aimed to analyse the results in patients with adolescent idiopathic scoliosis who underwent posterior correction with pedicle screw instrumentation. This prospective study investigated the magnitude of rib humps before and after the operation when the patient was in Adam9s forward bending posture. Also preoperatively, a flexion and derotation manoeuvre was performed and the corrected rib prominence was measured. This is compared to the magnitude of the rib hump present postoperatively at three months9 follow up. Seven consecutive patients with adolescent idiopathic scoliosis that underwent posterior surgical correction. Clinical measurement of rib prominence using scoliometer. The magnitude of the curve improved from a mean preoperative Cobb angle of 53.6+/−11.2° (range 45.3–72.5°) to a mean postoperative Cobb angle of 7.8+/−9.3° (range 0.4–17.6°). The mean preoperative magnitude of the rib hump was 12.3+/−6.9° (range 5-20°) which was then corrected to a mean magnitude of 1.3+/−2.2° (range 0-5°) by performing the above described flexion derotation manoeuvre. The mean postoperative magnitude of the rib hump was 3.0+/−3.1° (range 0-8°) with the patient in Adam9s forward bend position. There was positive correlation between the postoperative residual rib hump and the reduced rib hump measured preoperatively using our described technique (r=0.8,p=0.05). This flexion derotation test is a useful in assessing the amount of postoperative persistent rib hump after posterior correction of adolescent idiopathic scoliosis using pedicle screw instrumentation with derotation technique.

Total Sagittal Spinal Alignment in Patients With Lumbar Canal Stenosis Accompanied by Intermittent Claudication

Cross-sectional study of total sagittal spinal alignment in lumbar spinal canal stenosis (LCS) patients with and without intermittent claudication. To evaluate total sagittal spinal alignment in LCS. The sagittal spinal alignment is an important factor in the management of lumbar degenerative diseases and lower back pain. Patients with LCS accompanied by intermittent claudication adopt a forward-bending posture during walking. However, few studies have quantitatively assessed the abnormal posture in LCS in relation to clinical symptoms. This study analyzed 93 patients with LCS. They were divided into two groups according to the presence of neurogenic intermittent claudication; patients of the Claudicant group had intermittent claudication of the cauda equina (n = 53; mean age, 66.7) and those of the Nerve root group had no claudication (n = 40; mean age, 67.0). The following parameters were measured on the lateral whole-spine standing radiographs: the distance between the C7 plumb line and the posterior superior corner on the superior margin of S1 (sagittal vertical axis), the angle between the superior margin of the first lumbar vertebra and the first sacral vertebra (L1S1), lumbar lordotic angle, pelvic tilting angle (PA), and pelvic morphologic angle (PRS1). The sagittal vertical axis of the Claudicant group (57.6 +/- 37.5 mm) was significantly larger than that of the Nerve root group (40.3 +/- 42.3 mm) and was larger in both groups compared with the standard values. Lumbar lordotic angle was smaller (18.8 degrees +/- 13.2 degrees ) and pelvic tilting angle was larger (27.2 degrees +/- 8.3 degrees ) in patients with the Claudicant group than those with the Nerve root group (22.4 degrees +/- 14.0 degrees and 22.7 degrees +/- 7.2 degrees , respectively). Patients of the Claudicant group exhibited forward bending of the trunk and pelvis backtilt, compared with those of the Nerve root group.

1P1-C03 農作業軽労化支援アシストスーツの開発

Farmers and farm workers face some of the highest risks of work-related musculoskeletal injury caused by forward bending posture of the crop work or the heavy weight transportation. Therefore we performed biomechanical assessment for identifying risk factors involved in agricultural manual work. In this study, we developed the prototype personal weight transfer device, which reduce loads on the spine under simulated stooped postures. Moreover, we compared EMG value reduction effects by experiment.

Static pelvic obliquity can influence clinical assessment of trunk rotation in idiopathic scoliosis

Materials and methods The ATR was measured in 25 girls with idiopathic scoliosis (study group), age 13 to 19 years (mean 15.6 ± 1.8 years) and in 25 healthy girls (control group), age 12 to 16 years (mean 14.2 ± 0.9 years). In the study group the Cobb angle revealed curves ranging from 35.0° to 92.0° (mean 54.4° ± 18.0°) in the lumbar spine and 38.0° to 93.0° (mean 60.7° ± 17.3°) in the thoracic spine. The Bunnell scoliometer was then used in two positions: sitting and standing, both forward bending positions. The scoliometer readings were noted at four levels of the spine: high thoracic, main thoracic, lumbar and sacral. Then, the measurements were repeated in the same subjects and at the same four levels of the spine, but after leveling the left or the right side of the pelvis using a 1-2 cm thick shoe lift. Results When compared to the classical forward bending position, the ATRs were significantly different after the shoe lifts were applied. Typical patterns of alternatively raised or lowered ATRs within adjacent spinal levels were also identified. The difference depended on the shoe lift height and on the spinal level: the change was 1.5°-4.5° of rotation within the lumbar spine; 1.2° 3.8° of rotation within the thoracolumbar spine, and 0.7° to 2.4° of rotation within the high thoracic spine.

Study of body mass (BMI) index and truncal asymmetry (TA) in healthy adolescents

A group of 5953 adolescents, ages 11-17 years (2939 boysand 3014 girls) were examined in a school screening pro-gram using two standard positions: standing forwardbending (FB) and seated forward bending. TA was evalu-ated in both positions using a Pruijs scoliometer whichmeasured the angle of trunk inclinations (ATIs) across theback at each of three regions: thoracic, thoracolumbar andlumbar. An abnormal ATI was defined as being beyond 2standard deviations from the mean for region, age, genderand position, and this was termed severe TA. Each childwas assigned to a relatively lower or relatively higher BMIgroup using a median value of BMI by age and sex. The sit-ting FB position is thought to express intrinsic TA freefrom extrinsically-induced effects of any leg-length ine-quality.

Relatively lower body mass index is associated with an excess of severe truncal asymmetry in healthy adolescents: Do white adipose tissue, leptin, hypothalamus and sympathetic nervous system influence truncal growth asymmetry?

BackgroundIn healthy adolescents normal back shape asymmetry, here termed truncal asymmetry (TA), is evaluated by higher and lower subsets of BMI. The study was initiated after research on girls with adolescent idiopathic scoliosis (AIS) showed that higher and lower BMI subsets discriminated patterns of skeletal maturation and asymmetry unexplained by existing theories of pathogenesis leading to a new interpretation which has therapeutic implications (double neuro-osseous theory).Methods5953 adolescents age 11–17 years (boys 2939, girls 3014) were examined in a school screening program in two standard positions, standing forward bending (FB) and sitting FB. The sitting FB position is thought to reveal intrinsic TA free from back humps induced by any leg-length inequality. TA was measured in both positions using a Pruijs scoliometer as angle of trunk inclinations (ATIs) across the back at each of three spinal regions, thoracic, thoracolumbar and lumbar. Abnormality of ATIs was defined as being outside 2 standard deviations for each age group, gender, position and spinal region, and termed severe TA.ResultsIn the sitting FB position after correcting for age,relatively lower BMIs are statistically associated with a greater number of severe TAs than with relatively higher BMIs in both girls (thoracolumbar region) and boys (thoracolumbar and lumbar regions).The relative frequency of severe TAs is significantly higher in girls than boys for each of the right thoracic (56.76%) and thoracolumbar (58.82%) regions (p = 0.006, 0.006, respectively). After correcting for age, smaller BMIs are associated with more severe TAs in boys and girls.DiscussionBMI is a surrogate measure for body fat and circulating leptin levels. The finding that girls with relatively lower BMI have significantly later menarche, and a significant excess of TAs, suggests a relation to energy homeostasis through the hypothalamus. The hypothesis we suggest for the pathogenesis of severe TA in girls and boys has the same mechanism as that proposed recently for AIS girls, namely: severe TAs are initiated by a genetically-determined selectively increased hypothalamic sensitivity (up-regulation, i.e. increased sensitivity) to leptin with asymmetry as an adverse response to stress (hormesis), mediated bilaterally mainly to the growing trunk via the sympathetic nervous system (leptin-hypothalamic-sympathetic nervous system (LHS) concept). The putative autonomic dysfunction is thought to be increased by any lower circulating leptin levels associated with relatively lower BMIs. Sympathetic nervous system activation with asymmetry leads to asymmetries in ribs and/or vertebrae producing severe TA when beyond the capacity of postural mechanisms of the somatic nervous system to control the shape distortion of the trunk. A test of this hypothesis testing skin sympathetic responses, as in the Rett syndrome, is suggested.

Trunk asymmetry in normal juveniles

MATERIAL AND METHOD: The scoliometer readings in both standing and sitting forward bending position (FBP) of 3301 children, (1645 boys, 1656 girls) aged from 3 to 9 years old, were studied. TA was quantified by measuring angle of trunk rotation (ATR) and children were divided in two groups. In group I the ATR was 1AE to 6AE degrees and in group II ≥7AE. STATA 9.0 statistical package was used for the analysis.

Trunk asymmetry in juveniles

BackgroundTrunk asymmetry (TA) is a common phenomenon in children, but its incidence in juveniles is not known. The present cross sectional study reports TA in normal juveniles and provides data which describe the evolution of TA from early childhood to adolescence.Materials and methodsThe scoliometer readings in both standing and sitting forward bending position (FBP) of 3301 children, (1645 boys, and 1656 girls) aged from 3 to 9 years old were studied. TA was quantified by measuring angle of trunk rotation (ATR) and children were categorized as symmetric (ATR = 0°), mild asymmetric (ATR 1° – 6°) and severely asymmetric (ATR ≥ 7°). The difference of TA between standing and sitting FBP as well as differences between boys and girls in frequency of TA were also calculated. The scoliometer readings were analyzed by age to reveal at which age the juvenile pattern of TA changes into the adolescent one.Results74.2% of boys and 77% of girls were symmetric (ATR = 0°) in the thoracic region in standing FBP, while 82.7% of boys and 84.1% of girls were symmetric in the thoracic region in sitting FBP. Juvenile girls are more symmetric than boys but severe TA was found almost the same between the two genders. A significant reduction in the frequency of mild TA from standing into sitting FBP, in all the examined regions in both boys and girls was found, but in severe TA this reduction is very small. Analysing scoliometer readings by age it appears that significant TA changes take place between 8–9 years of age for boys and between 6–7 and 8–9 years for girls. TA in boys is changing into the adolescent pattern at a later age than in girls.ConclusionJuveniles were found more symmetric than adolescents, who were studied previously in a different study. Furthermore, juvenile girls were found more symmetric than boys. Juvenile TA pattern seems to be in accordance with the higher incidence of juvenile idiopathic scoliosis in boys. Furthermore, severe TA, which could be correlated with a scoliotic curve, was found to be more common to the left side. The present report provides information about the variability of back morphology in normal juveniles. The amount of TA in children is the indicator for referral and further orthopaedic assessment if a spinal curve is detected, but can also be used as a baseline for further research on idiopathic scoliosis aetiology.

Individual, Work-, and Flight-Related Issues in F-16 Pilots Reporting Neck Pain

Neck pain is a common problem in F-16 pilots. A cross-sectional survey was used to determine the self-reported 1-yr prevalence of neck pain and to compare individual, work-related, and flight-related characteristics in F-16 pilots with and without neck pain. There were 90 male F-16 pilots of the Belgian Air Force and The Royal Netherlands Air Force who voluntarily completed an anonymous survey. The 1-yr prevalence of neck pain was 18.9%. Pilots were divided into two groups: healthy (HG) and neck pain group (NPG). This study could not identify individual or specific flight-related differences between these two groups. High force demands, often sitting for a long time, frequently holding the neck in a forward bent posture, and being physically tired were all physical work-related factors that were reported significantly more often in the NPG. The NPG also reported significantly more psychosocial factors, such as being mentally tired at the end of the day and being annoyed by others at the workplace. Since the specific flight-related factors were not significantly different between the HG and the NPG, physical and psychosocial factors could have been important factors in the development or maintenance of neck pain in F-16 pilots. The results of this study highlight for the first time that, in addition to flight-related issues, other aspects must be considered in analyzing neck pain. These other aspects stress the importance of a broader approach when considering neck pain, even in this population that is exposed to very high loads during flight.

Postural Support by a Standing Aid Alleviating Subjective Discomfort among Cooks in a Forward‐bent Posture during Food Preparation

In this study, we evaluated the effects on subjective discomfort among cooks during food preparation through use of a standing aid that we developed to alleviate the workload on the low back in the forward-bent posture. Twelve female cooks who worked in a kitchen in a nursing home were asked to prepare foods in 2 working postures: (a) supported by the standing aid (Aid) and (b) without the aid (No aid). They were instructed to evaluate discomfort in 13-body regions during food preparation and the degree of fatigue at the day's end and to enter their ratings after the end of the workday. Since a significant correlation was observed between body height and the improvement effect of discomfort through use of the standing aid, cooks were divided into two groups according to the height, and ratings were analyzed in each group. Among the tall cooks, subjective discomfort in the low back and the front and back of thighs was significantly less with the Aid posture than with the No aid posture. However, in short cooks these values tended to increase in the Aid posture compared with the No aid posture. The results suggest that the standing aid was effective in alleviating tall cooks' workload on the low back in the forward-bent posture.

Sitting forward bending position versus standing position for studying the back shape in scoliotic children

Sitting forward bending position versus standing position for studying the back shape in scoliotic children

An Electromyographic Analysis of Trunk and Hip Extensor Muscles During Isometric Pulling Up in the Forward Bending Posture

An Electromyographic Analysis of Trunk and Hip Extensor Muscles During Isometric Pulling Up in the Forward Bending Posture

Study of trunk asymmetry in normal children and adolescents

The scoliometer readings in both standing and sitting position of 2071 children and adolescents (1099 boys and 972 girls) aged from 5 to 18 years old were studied. The angle of trunk rotation (ATR) was measured, in order to quantify the existing trunk asymmetry. Children and adolescents were divided in two groups according to the severity of trunk asymmetry. In the first group asymmetry was 1 to 6 degrees and in the second group was 7 or more degrees. Radiographic and leg length inequality evaluation were also performed in a number of children. The mean frequency of symmetric (ATR = 0 degrees) boys and girls was 67.06% and 65.01% for the standing screening position and 76.5% and 75.1% for the sitting position, respectively. The mean difference of frequency of asymmetry (ATR > 0 degrees) at standing minus sitting forward bending position for boys and girls was 10.22% and 9.37%, respectively. The mean frequency of asymmetry of 7 or more degrees was 3.23% for boys and 3.92% for girls at the standing forward bending position and 1.62% and 2.21% at the sitting, respectively. Girls are found to express higher frequency of asymmetry than boys. Right trunk asymmetry was more common than left. The sitting position is the preferred screening position for examining the rib or loin hump during school screening as it demonstrates the best correlation with the spinal deformity exposing the real trunk asymmetry.

Rasterstereographic analysis of axial back surface rotation in standing versus forward bending posture in idiopathic scoliosis

The forward bending test according to Adams and rib hump quantification by scoliometer are common clinical examination techniques in idiopathic scoliosis, although precise data about the change of axial surface rotation in forward bending posture are not available. In a pilot study the influence of leg length inequalities on the back shape of five normal subjects was clarified. Then 91 patients with idiopathic scoliosis with Cobb-angles between 20 degrees and 82 degrees were examined by rasterstereography, a 3D back surface analysis system. The axial back surface rotation in standing posture was compared with that in forward bending posture and additionally with a scoliometer measurement in forward bending posture. The changes of back shape in forward bending posture were correlated with the Cobb-angle, the level of the apex of the scoliotic primary curve and the age of the patient. Averaged over all patients, the back surface rotation amplitude increased from 23.1 degrees in standing to 26.3 degrees in forward bending posture. The standard deviation of this difference was high (6.1 degrees ). The correlation of back surface rotation amplitude in standing with that in forward bending posture was poor (R (2)=0.41) as was the correlation of back surface rotation in standing posture with the scoliometer in forward bending posture measured rotation (R (2)=0.35). No significant correlation could be found between the change of back shape in forward bending and the degree of deformity (R (2)=0.07), likewise no correlation with the height of the apex of the scoliosis (R (2)=0.005) and the age of the patient (R (2)=0.001). Before forward bending test leg length inequalities have to be compensated accurately. Compared to the standing posture, forward bending changes back surface rotation. However, this change varies greatly between patients, and is independent of the type and degree of scoliosis. Furthermore remarkable differences were found between scoliometer measurement of the rib hump and rasterstereographic measurement of the vertebral rotation. Therefore the forward bending test and the identification of idiopathic scoliosis rotation by scoliometer can be markedly different compared to rasterstereographic surface measurement in the standing posture.

Effects of changes in skiing posture on the kinetics of the knee joint

This study was performed to investigate the effects of changes in the skiing posture on mechanical stress across the knee joint. The aim of the present study was to establish a safer form of skiing for the prevention of injury to the anterior cruciate ligament of the knee (ACL). Ten healthy volunteers were placed on a force plate on an artificial slope, and assumed forward and backward bending postures with a single leg by changing their centre of gravity. The knee flexion angles were limited to approximately 30 degrees by orthotics in each posture. Joint moments of the lower extremity were analyzed using a motion analysis system, and the muscle activities of the lower extremity were recorded by EMG and digitised to integrated EMG in each posture. In addition, extrusion of the lower leg by the boot was measured using a force sensor sheet inserted behind the calf. We found that the extension moment of the hip and ankle joints, and muscular activity of the hamstrings were increased in forward bending, whereas the extension moment of the knee and muscular activity of the quadriceps were decreased. Conversely, the muscular activity of the quadriceps, the flexion moment of the hip, extension moment of the knee joint, and pressure of the boot were increased in backward bending, whereas muscular activity of the hamstrings was decreased. The dependency on the hamstrings increased in forward bending in a skiing posture on a slope with slight knee flexion. Therefore, forward bending seemed to be an advantageous posture for the prevention of ACL injury. Conversely, in a backward bending skiing posture, the extension moment of the knee joint produced by muscle contraction of the quadriceps also increased imbalance in the hamstrings. The results of this study suggest that the internal force exerted by the quadriceps, in addition to the passive factor of extrusion of the lower leg by the boot, may contribute to non-contact ACL injury in a backward bending posture while skiing.

Modelling and simulation of the intervertebral movements of the lumbar spine using an inverse kinematic algorithm

An inverse kinematic model is presented that was employed to determine the optimum intervertebral joint configuration for a given forward-bending posture of the human trunk. The lumbar spine was modelled as an open-end, kinematic chain of five links that represented the five vertebrae (L 1-L5). An optimisation equation with physiological constraints was employed to determine the intervertebral joint configuration. Intervertebral movements were measured from sagittal X-ray films of 22 subjects. The mean difference between the X-ray measurements of intervertebral rotations in the sagittal plane and the values predicted by the kinematic model was less than 1.6 degrees. Pearson product-moment correlation R was used to measure the relationship between the measured and predicted values. The R-values were found to be high, ranging from 0.83 to 0.97, for prediction of intervertebral rotation, but poor for intervertebral translation (R= 0.08-0.67). It is concluded that the inverse kinematic model will be clinically useful for predicting intervertebral rotation when X-ray or invasive measurements are undesirable. It will also be useful to biomechanical modelling, which requires accurate kinematic information as model input data.

Shape and thickness of cushion in a standing aid to support a forward bending posture: effects on posture, muscle activities and subjective discomfort.

In order to prevent low back pain (LBP) during dishwashing, we developed three types of aid with a thick cushion for supporting the shins and evaluated the effects of the standing aid on the subjective discomfort and muscle activities. Nine female volunteers were asked to wash plates in each of four working postures: (a) without the standing aid, (b) with the round type of aid, (c) with the small rectangular type of aid, and (d) with the large rectangular type of aid. With the three types of aid, the subjects were instructed to support the shins with the standing aid and to support the abdomen with the edge of a kitchen counter. In the three postures with the standing aid, 21.5 +/- 10.0% of the weight was supported with the standing aid and the kitchen counter. The subjective discomfort was milder and the muscle activity level in the low back was lower in the three postures with the standing aid than in the posture without the aid. It was thought that the round type of aid would be more effective in decreasing the discomfort in many of body regions and the muscle load on the low back than either of the rectangular types of aid. Therefore, it was suggested that the standing aid had the desired effect in decreasing discomfort and muscle load on the low back during dishwashing.