Lordosis in Humans.

Despite progress in attractiveness research, we have yet to identify many fitness-relevant cues in the human phenotype or humans' psychology for responding to them. Here, we test hypotheses about psychological systems that may have evolved to process distinct cues in the female lumbar region. The Fetal Load Hypothesis proposes a male preference for a morphological cue: lumbar curvature. The Lordosis Detection Hypothesis posits context-dependent male attraction to a movement: lordosis behavior. In two studies (Study 1 N: 102, Study 2 N: 231), we presented men with animated female characters that varied in their lumbar curvature and back arching (i.e., lordosis behavior). Irrespective of mating context, men's attraction increased as lumbar curvature approached the hypothesized optimum. By contrast, men experienced greater attraction to lordosis behavior in short-term than long-term mating contexts. These findings support both the Lordosis Detection and Fetal Load Hypotheses. Discussion focuses on the meaning of human lordosis and the importance of dynamic stimuli in attractiveness research.

Modifications of the locomotor system in habitually quadrupedal humans.

The acquisition of habitual bipedal locomotion, which resulted in numerous modifications of the skeleton was a crucial step in hominid evolution. However, our understanding of the inherited skeletal modifications versus those acquired while learning to walk remains limited. We here present data derived from X-rays and CT scans of quadrupedal adult humans and compare the morphology of the vertebral column, pelvis and femur to that of a bipedal brother. We show how a skeleton forged by natural selection for bipedal locomotion is modified when used to walk quadrupedally. The quadrupedal brother is characterised by the absence of femoral obliquity, a very high anteversion angle of the femoral neck, a very high collo-diaphyseal angle and a very reduced lordosis. The differences in the pelvis are more subtle and complex, yet of functional importance. The modification of the ischial spines to an ischial ridge and the perfectly rounded shape of the sacral curvature are two unique features that can be directly attributed to a quadrupedal posture and locomotion. We propose a functional interpretation of these two exceptional modifications. Unexpectedly, the quadrupedal brother and sister show a greater angle of pelvic incidence compared to their bipedal brother, a trait previously shown to increase with learning to walk in bipedal subjects. Moreover, the evolution from an occasional towards a permanent bipedality has given rise to a functional association between the angle of pelvic incidence and the lumbar curvature, with high angles of incidence and greater lumbar curvature promoting stability during bipedal locomotion. The quadrupedal brother and sister with a high angle of incidence and a very reduced lordosis thus show a complete decoupling of this complex functional integration.

Women Walk in High Heels: Lumbar Curvature, Dynamic Motion Stimuli and Attractiveness.

Previous studies have demonstrated that the angle of women's lumbar curvature affects men's attractiveness judgments of them. The theoretically optimal angle of lumbar curvature provides better resistance against both hyperlordosis and hypolordosis as biomechanical costs of a bipedal fetal load that could impair a woman's fertility. Since men find this attribute attractive, women aim to emphasize it by wearing high-heeled shoes. The primary objective of the present study was to test this evolutionary hypothesis using short videos presenting women walking by the camera. In line with previous findings based on static stimuli (photographs), dynamic stimuli (videos) presenting women walking in high-heeled shoes were expected to elicit increased attractiveness ratings as compared to women wearing flat shoes, which would be associated with the angle of lumbar curvature. Videos were taken of 52 female models walking in two conditions (i.e., wearing either high-heeled or flat shoes). A total of 108 participants (61 males, 47 females) rated the walking models' physical attractiveness in an online setting. Each model's lumbar curvature was measured both in high heels and in flat shoes using photographs taken of them prior to each video recording. The results showed that wearing high heels consistently increased the models' attractiveness, regardless of whether or not it decreased their natural difference from the theoretically optimal angle of lumbar curvature. Both male and female observers showed this positive effect. Furthermore, a negative correlation was found between the models' body mass index (BMI) and their perceived attractiveness scores in both conditions.

Residual lumbar curvature that developed during adolescence accelerates intervertebral disc degeneration in adulthood.

PURPOSE: To elucidate the influence of spinal deformity in adolescent idiopathic scoliosis (AIS) on lumbar intervertebral disc (IVD) degeneration in adulthood using magnetic resonance imaging (MRI). METHODS: A total of 102 patients (8 men, 94 women; mean age, 31.4 years) who had developed idiopathic scoliosis at the age of 10-18 years and underwent preoperative lumbar spine MRI at the age of ≥ 20 were included in the study. Twenty volunteers (3 men, 17 women; mean age, 33.6 years) without scoliosis were assessed as controls. We divided the adult scoliosis patients into two groups: Group A consisted of patients with lumbar modifier A, and Group BC consisted of those with modifiers B and C. IVD degeneration from L1/2 to L5/S1 was assessed by MRI. The Scoliosis Research Society-22 (SRS-22) patient questionnaire was used in the patients' clinical assessment. RESULTS: There were 40 patients in the Group A and 62 in the Group BC. Compared to the control groups, significant IVD degeneration was observed at L2/3 and L3/4 in Group A, and at all levels except for L5/S1 in Group BC. The proportion of degenerated IVDs patients (Grades 1c and 2) was significantly higher in Group BC than those in Group A at L3/L4 and L4/L5. Furthermore, the severity of IVD degeneration was significantly greater in the group BC than in the group A at all levels, except for L5/S1, especially in patients aged > 30 years. The mean scores of all subdomains in the SRS-22 questionnaire were comparable between the two groups. CONCLUSION: Our study showed that the residual lumbar curvature from AIS may have accelerated IVD degeneration in adulthood, especially in patients aged > 30 years. LEVEL OF EVIDENCE: III.

Psychometric Properties of the iHandy Level Smartphone Application for Measuring Lumbar Spine Range of Motion and Lordosis: A Systematic Review of the Literature.

CONTEXT: Advent of smartphones has brought a wide range of clinical measurement applications (apps) within the reach of most clinicians. The vast majority of smartphones have numerous built-in sensors such as magnetometers, accelerometers, and gyroscopes that make the phone capable of measuring joint range of motion (ROM) and detecting joint positions. The iHandy Level app is a free app which has a visual display alike with the digital inclinometer in regard to numeric size. OBJECTIVE: The purpose of this systematic review was to evaluate available evidence in the literature to assess the psychometric properties (ie, reliability and validity) of the iHandy Level app in measuring lumbar spine ROM and lordosis. METHODS: PubMed/MEDLINE, Scopus, Ovid, Google Scholar, and ScienceDirect were searched from inception to September 2018 for single-group repeated-measures studies reporting outcomes of lumbar spine ROM or lordosis in adult individuals without symptoms of low back pain (LBP) or patients with LBP. The quality of each included study was assessed using the Quality Appraisal of Reliability Studies checklist. RESULTS: A total of 4 studies with 273 participants were included. Two studies focused on measuring active lumbar spine ROM, and 2 studies evaluated lumbar spine lordosis. Three studies included asymptomatic subjects, and one study recruited patients with LBP. The results showed that the iHandy Level app has sufficient psychometric properties for measuring standing thoraco-lumbo-sacral flexion, extension, lateral flexion, isolated lumbar spine flexion ROM, and lumbar spine lordosis in asymptomatic subjects. One study reported poor concurrent validity with a bubble inclinometer (r = .19-.53), poor intrarater reliability (intraclass correlation coefficient = .19-.39), and poor to good interrater reliability (intraclass correlation coefficient = .24-.72) for the measurement of active lumbar spine ROM using the iHandy Level app in patients with LBP. CONCLUSIONS: This review provided a valuable summary of the research to date examining the psychometric properties of the iHandy Level app for measuring lumbar spine ROM and lordosis.

Revisiting the effect of manipulating lumbar stability with load magnitudes and positions: The effect of sex on trunk muscle activation.

BACKGROUND: Lumbar spine stability is regularly studied by positioning different loads at different heights and distance and measuring trunk muscle activation changes. Some of these studies have reported sex differences, but this needs to be revisited while controlling for confounding factors. METHOD: 20 males and 20 females sustained three static standing postures, with various loads (0, 5 and 10% of body weight), to evaluate the effect of height and distance. Activation of 12 trunk muscles was recorded with surface electromyography (EMG). RESULTS: Females activated their external obliques a little more than males, with increases ranging between 1.5 and 2.3% of maximal voluntary activation (MVA), which corresponds to strong effect sizes (Cohen's d ranging between 0.86 and 1.13). However, the significant Sex × Height, Sex × Distance and Sex × Load interactions observed for different trunk muscles led to small differential effects (≤1% MVA). Increasing load height slightly increased and decreased back and abdominal muscle activation, respectively, generally by less than 1% MVA. CONCLUSION: The higher activation of the external obliques observed in females might be of clinical value, relative to the required overall trunk muscle activation (5%), to preserve lumbar stability. Other effects were negligible.

MRI assessment of the correlation between lumbar physiological curvature and Pfirrmann grading of lumbar intervertebral disc in young patients / 实用放射学杂志

Objective To investigate the correlation between lumbar physiological curvature and Pfirrmann grading of lumbar intervertebral disc in young patients with lower lumbar pain.Methods 1 1 1 cases with lower lumbar pain were analyzed retrospectively by lumbar MRI examination.The MRI image was reviewed by two radiologists,and the degree of lumbar physiological curvature and lumbar disc degeneration were observed.Chi square test was applied to the statistical results.Results Final analysis was performed on 300 discs in 60 cases of patients with lumbar physiological curvature straightening.Among them,209 were grade Ⅰ-Ⅱ(70%),45 grade Ⅲ(15%),35 grade Ⅳ(11%)and 11 grade Ⅴ(4%)in Pfirrmann grading.In total of 255 discs of 51 cases with normal physiological curvature of the spine,there were 212 (83%)of Pfirrmann grade Ⅰ-Ⅱ,22 of grade Ⅲ(9%),19 of grade Ⅳ(7%)and 2 of grade Ⅴ(1 %).There was statistical difference between the lumbar physiological curvature straightening and the normal lumbar physiological curvature group (P< 0.05).The proportions of degeneration of Ⅰ-Ⅱ in the lumbar physiological curvature group was lower than that in normal lumbar curvature group,while the proportions of gradeⅢ,ⅣandⅤdegeneration in the lumbar physiological curvature group were higher than that in normal lumbar curvature group.Conclusion Stratification lumbar physiologic curvature is an important factor for lumbar disc degeneration and easy to cause Pfirrmann gradeⅣ-Ⅴdegeneration in young patients.

Why Women Wear High Heels: Evolution, Lumbar Curvature, and Attractiveness.

Despite the widespread use of high-heeled footwear in both developing and modernized societies, we lack an understanding of this behavioral phenomenon at both proximate and distal levels of explanation. The current manuscript advances and tests a novel, evolutionarily anchored hypothesis for why women wear high heels, and provides convergent support for this hypothesis across multiple methods. Using a recently discovered evolved mate preference, we hypothesized that high heels influence women's attractiveness via effects on their lumbar curvature. Independent studies that employed distinct methods, eliminated multiple confounds, and ruled out alternative explanations showed that when women wear high heels, their lumbar curvature increased and they were perceived as more attractive. Closer analysis revealed an even more precise pattern aligning with human evolved psychology: high-heeled footwear increased women's attractiveness only when wearing heels altered their lumbar curvature to be closer to an evolutionarily optimal angle. These findings illustrate how human evolved psychology can contribute to and intersect with aspects of cultural evolution, highlighting that the two are not independent or autonomous processes but rather are deeply intertwined.

Loading of the lumbar spine during backpack carriage.

Backpack carriage is significantly associated with a higher prevalence of low back pain. Elevated compression and shear forces in the lumbar intervertebral discs are known risk factors. A novel method of calculating the loads in the lumbar spine during backpack carriage is presented by combining physical and numerical modelling. The results revealed that to predict realistic lumbar compression forces, subject-specific lumbar curvature data were not necessary for loads up to 40 kg. In contrast, regarding shear forces, using subject-specific lumbar curvature data from upright MRI measurements as input for the rigid body model significantly altered lumbar joint force estimates.

Using a spine stabilizer instrument to control postural sway in standing lumbar curvature measurements by flexible curve.

BACKGROUND AND OBJECTIVE: The amount of postural sway and sagittal deviation of lumbar lordosis angle in measurements of standing lumbar curvature obtained by flexible curve can be decreased when using a spine stabilizer instrument. However, this assumption has not been investigated so far. This study aims to determine the effect of using a spine stabilizer instrument on the validity, reliability, and standard errors of measurement of flexible curve in the standing lumbar curvature measurements. MATERIAL AND METHOD: Thirty-four volunteer men aged between 19 and 30 years participated in the study By using a 50-cm flexible curve, with and without spine stabilizer instrument, and a lumbar simple lateral radiograph (LSLR), the standing lumbar curvature was measured by three methods for each subject. These methods were called A, B and C, respectively. RESULTS: By using the Pearson's correlation analysis at significance level of 0.05, the coefficient of correlation between standing lumbar curvature measurements in methods A and B with C were 0.95 and 0.84, respectively. In addition, the intraclass correlation coefficient for methods A and B were 0.94 and 0.79, respectively. Also, results of the one-way analysis of variance for comparison of pairs indicated a significant difference in the mean values of standing lumbar curvature angles between methods B and C. CONCLUSIONS: Results indicated the flexible curve was an appropriate instrument for standing lumbar curvature measurements. Using spine stabilizer instrument to control postural sway increases the validity and reliability of flexible curve method and decreases its standard errors of measurement.

Repercussões da curvatura lombar nas características da lombalgia em praticantes de voleibol / Lumbar curvature repercussions on lumbar pain characteristics in volleyball players

INTRODUÇÃO: A dor lombar vem sendo um achado comum em atletas e indivíduos adultos jovens. Das diversas causas deste sintoma, as alterações mecânico-posturais estão entre as mais comuns na população. OBJETIVO: Este estudo foi realizado com o intuito de correlacionar a intensidade e os aspectos da lombalgia com as medidas angulares da curvatura lombar em praticantes de voleibol. MÉTODOS: Participaram desta pesquisa 42 jovens atletas, de ambos os sexos, com idade entre 14 e 18 anos, divididos em dois grupos, o grupo sem dor e o grupo com dor lombar. Ambos responderam a uma ficha de avaliação inicial, porém a escala analógica visual de dor foi aplicada apenas nos indivíduos do grupo com dor. A seguir, todos os participantes foram submetidos ao exame radiológico da coluna lombar e o ângulo de Cobb foi obtido sobre as radiografias no plano sagital. RESULTADOS: Os resultados foram analisados através da estatística descritiva e inferencial, demonstrando que, para p < 0,05, os valores médios dos ãngulos entre os dois grupos analisados não diferem significativamente. CONCLUSÃO: Conclui-se que não houve correlação entre a curvatura da coluna lombar e a lombalgia em jovens praticantes de voleibol.

INTRODUCTION: Although not frequent, lately there have been cases of young adults and athletes complaining of lumbar pain, this being one of the most common causes of mechanical postural alterations. OBJECTIVE: In view of this, it was decided to carry out this study correlating the intensity of lumbar pain with its anatomical/physiological characteristics, using the measurements of the angles of lumbar curvature in volleyball players. METHODS: 42 athletes including males and females from 14 to 18 years of age took part. These volunteers were divided into two groups according to the symptoms of their lumbar pain: one group with lumbar pain and the other with no lumbar pain. The initial procedure for both groups was to complete a structured functional assessment form. Only the group with lumbar pain then had the visual analogical scale of pain applied. After this stage, both groups were submitted to a radiological examination of the lumbar region of the spine, which was used to calculate the Cobb angle examining the x-rays on the sagital plane. RESULTS: The results were analysed using descriptive and inferential statistics, regarding as statistically significant p<0.05 the difference of the mean values of the angles found in the measurements taken in the two groups. Statistical analysis using the qui-square test, the likeli hood ratio test and Student's t-test showed no statistically significant difference. CONCLUSION: this study concluded that the differences found through the measurement of curvature of the lumbar region of the spine have no influence on the appearance and the intensity of lumbar pain in young volleyball players.

A clinic study of trunk muscle strength and lumbar curvature in young patients with low back pain / 中华物理医学与康复杂志

0. 05), TAE of flexors in patients were lower than those in the healthysubjects(P 0. 05 ). F/E in patients were greater than those in healthy subjects(P

BIOMECHANICAL STUDY OF TRUNK MUSCLE STRENGTH AND INTERRELATED STUDY IN PATIENTS WITH LOW BACK PAIN CAUSED BY MILITARY TRAINING / 解放军医学杂志

To ascertain the change of trunk muscle strength and lumbar curvature and cross sectional area of M. sacrospinalis in low back pain caused by military training, the indexes of trunk muscle strength (PT/BW, TAE, F/E) were measured in patients with low back pain and healthy subjects with CYBEX 6000 isokinetic testing system. The lumbar curvature was measured in lumbar X ray films on the lateral projection in standing position, and the cross sectional area of sacrospinalis was measured by ultrasonography. All of the indexes were compared between the two groups.The results showed PT/BW of flexors was not significantly different between the patients and healthy subjects, TAE of flexors in patients was lower than that of healthy subjects ( P

Study of the lumbar curvature with various factors of pelvic inclination. Change of radiographic lumbar curvature according to hip joint flexion

The objective of this study was to investigate the influence of the hip flexion upon parameters that are indicators of spinal mobility. These parameters include intervertebral disc angle and lumbar curvature by measurement of the radiography in twenty eight healthy men. The state of knowledge of how these parameters relate to lumbar mobility have resolved. The results of the parameters showed negligible changes in relation to the mobility of lumbar spine according to angle of hip flexion except at L4-L5 intervertebral disc angle and lumbar curvature (p< 0.05). This results of study confirms that hip joint movement therapy can be applied to these norms in patient management in supine position of for the stable spinal injuries in the upper lumbar region during early phase.

The change in trunk muscle performance in recruits with low back pain caused by military training and its prevention / 解放军医学杂志

To elucidate the change in trunk muscle performance in patients with low back pain caused by military training. The indices of trunk muscle strength (PT/BW, TAE, F/E, ER), the cross-sectional area of sacrospinalis, the amplitude and the duration of EMG, and the lumbar curvature were measured in recruits with low back pain after military training (n=40)and healthy subjects(n=40).All of the indices were compared between two groups. It was found that except PT/BW and ER of flexors and cross-sectional area of sacrospinalis, there were significant differences between other indices of the patients compared with healthy subjects(P