Neutral lumbar spine sitting posture in pain-free subjects

Sitting is a common aggravating factor in low back pain (LBP), and re-education of sitting posture is a common aspect of LBP management. However, there is debate regarding what is an optimal sitting posture. This pilot study had 2 aims; to investigate whether pain-free subjects can be reliably positioned in a neutral sitting posture (slight lumbar lordosis and relaxed thorax); and to compare perceptions of neutral sitting posture to habitual sitting posture (HSP). The lower lumbar spine HSP of seventeen pain-free subjects was initially recorded. Subjects then assumed their own subjectively perceived ideal posture (SPIP). Finally, 2 testers independently positioned the subjects into a tester perceived neutral posture (TPNP). The inter-tester reliability of positioning in TPNP was very good (intraclass correlation coefficient (ICC) = 0.91, mean difference = 3% of range of motion). A repeated measures ANOVA revealed that HSP was significantly more flexed than both SPIP and TPNP (p <0.05). There was no significant difference between SPIP and TPNP (p >0.05). HSP was more kyphotic than all other postures. This study suggests that pain-free subjects can be reliably positioned in a neutral lumbar sitting posture. Further investigation into the role of neutral sitting posture in LBP subjects is warranted.     

Static trunk posture in sitting and standing during pregnancy and early postpartum

OBJECTIVE: To investigate the postural alignment of the upper body in the sagittal plane during sitting and standing postures as pregnancy progressed and then in the postpartum period. DESIGN: Longitudinal, repeated-measures design. SETTING: Biomechanics laboratory in an Australian university. PARTICIPANTS: A volunteer convenience sample of 9 primiparous and multiparous women and 12 nulliparous women serving as a control group. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Subjects were filmed while sitting and during quiet standing at intervals throughout pregnancy and at 8 weeks postpartum. A repeated-measures analysis of variance was used to assess systematic changes in the alignment of the pelvic, thoracic, and head segments, and the thoracolumbar and cervicothoracic spines. Student t tests were used to compare the postpartum and nulliparous control groups. RESULTS: There was no significant effect of pregnancy on the upper-body posture, although there was a tendency in some subjects for a flatter thoracolumbar spinal curve in sitting as pregnancy progressed. Postpartum during standing, the pelvic segment had a reduced sagittal plane anterior orientation, and the thoracolumbar spine was less extended, indicating a flatter spinal curve compared with the control group. CONCLUSIONS: There was no significant effect of pregnancy on upper-body posture during sitting and standing, although individuals varied in their postural response. A flatter spinal curve was found during standing postpartum.     

Spinal shrinkage during work in a sitting posture compared to work in a standing posture

Objective. The objective was to measure the possible differences in shrinkage of the thoracolumbar spine in subjects working in a sitting and a standing posture for 6.5 h at work, in a realistic work environment. The isolated shrinkage of the thoracic and the lumbar spine was also examined.

Study design. This study presents a new protocol to measure shrinkage of the thoracic and lumbar spine separately.

Background. Controversies still exist with regard to the load on the spine in a sitting compared to a standing position. Some report that shrinkage is greatest in the sitting position while others report the reverse. However, nothing is known about the height reduction of the thoracic and the lumbar spine during loading for 6.5 h in a real work environment. Therefore, the behaviour of the thoracic and the lumbar spine under practical condition has to be investigated.

Method. A stadiometer with a measurement error of 0.51 mm was used to measure changes in spinal height during work. To exclude first-time behaviour of the spine, a pre-test lasting 50 min was undertaken. The mean of the last three measurements was used as the reference height. During work, height measurements of the spine were performed every 20 min. To separate the behaviour of the thoracic and the lumbar spine, two benchmarks were placed at the vertebrae prominens and at the thoracic-lumbar junction. Shrinkage of the spine was investigated within three different cohorts: (I) work in a sitting posture for 6.5 h; (II) relaxed sitting for 2 h vs work for 2 h in a sitting position and (III) work in a standing position for 6.5 h.

Results. Relaxed sitting leads to a gain in stature compared to work in a sitting position for 2 h. The major gain in stature occurred in the lumbar spine. Comparison of cohort (III) working in a standing position with cohort (I) working in a sitting position shows that the shrinkage of the spine is greatest when work is performed in a standing posture. The major differences were found in the shrinkage of the lumbar spine e.g. shrinkage of the lumbar spine in the standing cohort (III) was 4.16 mm compared to 1.73 mm in the sitting cohort (I).

Conclusions. There is a gain in stature during relaxed sitting compared to work in a sitting posture. The load on the spine is greatest when work in a standing position is performed. The greater shrinkage of the lumbar spine during work in a standing position compared to a sitting posture is probably due to: (i) differences in lumbar lordosis and (ii) the effect of bending and torsion while handling the work materials.     

便携式站姿、坐姿人体平衡测试系统的研制

目的研制一套适用于人体站姿、坐姿平衡功能测量的便携式人体平衡功能测量系统。方法人体姿态发生变化后，运用光电技术和图像处理技术将固定在被试者头部中央视标移动轨迹转化为人体重心移动轨迹，通过对该轨迹的分析，定量测量出人体平衡功能。结果和结论设计出该系统。利用该系统对一志愿者饮酒前后的平衡功能进行测量比较，表明测量结果可靠。     

Measuring hypnotic responsiveness: A comparison of the barber suggestibility scale and the stanford hypnotic susceptibility scale,form a

The Barber Suggestibility Scale (BSS) and the Stanford Hypnotic Susceptibility Scale, Form A (SHSS:A) were administered, under both imagination and hypnotic-induction instructions, to 2 samples of 40 high-school students. The 2 scales were sufficiently correlated (.62 to .78, for objective and subjective scores) to indicate that, in general, they measure responses in the same broad domain. There is, however, a greater discrepancy between objective and subjective scores on the BSS than on the SHSS:A. The subjective scores are not independent of the objective scores, but correct the objective scores for pressure toward social compliance. Both scales are satisfactory for preliminary S-selection but limited as criteria for the range of hypnotic responsiveness.     

Design of a modular wheelchair with posture transformation capabilities from sitting to standing

Abstract

A significant part of world’s population is handicap, with majority suffering from lower body disabilities – the body waist down is paralysed or weak. In many of such cases, upper body of the affected person was found to be deemed fit and was able to perform all tasks, if feasible. Being able to transform posture from sitting to standing position independently, helps perform routine jobs with ease, increases employment prospects and improves blood circulation to name a few. Most of the existing wheelchair designs are expensive because of the electrical and electronics involved requiring added maintenance, or contain a variety of subsystems thus decreasing reliability. The objective is to further increase the posture transformation capabilities in terms of cost, user effort, maintenance and life. The modular wheelchair allows the user to use his/her own energy and bodyweight to shift from sitting to standing position and back, in single smooth movement with zero dependency on electrical/electronic parts. Detailed design of links, mechanisms and load calculations were performed as per standard requirements. Prototype of the proposed design was also made and successfully tested for all its design features and capabilities as per the design standards and conditions of physically challenged people.

• Implications for rehabilitation

• Five bar link mechanism helps to reduce manual effort.

• There is no dependency on auxiliary power source.

• It is a low cost rehabilitation solution with increased posture transformation capabilities.

• Increased body movements will help to increase self-confidence of disabled person.

• Easy sitting and standing capabilities will improve overall bodily functions and remove psychological barriers.

     

Sitting bodily configuration: A study investigating the intra-tester reliability of positioning subjects into a predetermined sitting posture

Sitting posture predominates in lifestyle and workplace, but quantitative postural designation is limited due to divergence of methodology used in the studies.To date, no study has investigated the upper body’s habitual or a predetermined sitting posture in healthy individuals assessing together pelvis, spine and head. The objectives were (i) assessment of intra-rater reliability of positioning subjects to a lordotic sitting posture and (ii) comparison of habitual sitting posture (HSP) with the lordotic posture. Another objective was to synthesize and propose an improved 3D model for pelvis, trunk and head to assess quantitatively the postural sagittal configuration.A single session test-retest design was employed. After power calculations 25 subjects were recruited. A repeated measure ANOVA revealed significant differences between HSP and the predetermined posture used in the study. Intra-rater reliability was analysed used the intra-class correlation coefficient (ICC) and also standard error of measurement (SEM) and smallest real difference (SRD) were calculated. The ICC values for all angles ranged from 0.85 to 0.98 indicating almost perfect agreement. The SEMs for all angles ranged in degrees from 0.65 to 1.50 and the SRDs from 1.80 to 4.16.This study provides the most specific sagittal measurement of surface spinal curves, head and pelvis position, in reference to a lordotic seated posture. The clinical significance of this study is reinforced by the fact that postural assessment is conducted by body surface evaluation. The results regarding reliability and SEMs established that healthy individuals can be reliably positioned in an upright lordotic sitting posture.     

Weight distribution in standing and sitting positions,and weight transfer during reaching tasks,in seated stroke subjects and healthy subjects

Background and Purpose. The recovery of sitting balance after a stroke is assumed to be essential to obtain independence in other vital functions. The purpose of the present study was to investigate weight distribution while sitting and standing still, and weight transfer during seated reaching tasks performed by stroke subjects and healthy subjects. Method. The study was cross‐sectional. Twenty‐one stroke subjects and 21 healthy subjects, matched by age and gender, participated. Main measures were weight distribution while standing and sitting still, and displacements of centre of pressure (COP) during seated reaching tasks. Data were collected using a balance performance monitor (BPM), including software. Results. Stroke subjects had less symmetrical weight distribution in standing than that of healthy subjects (p < 0.001). No significant differences between the groups were found while sitting still, and no associations between asymmetries in standing still and sitting positions within individual stroke subjects were found. Neither did the degree of weight distribution in sitting correspond to COP displacements in seated reaching tasks. However, COP displacement patterns in reaching tasks in the seated position were different in stroke subjects from those of healthy subjects. Stroke subjects showed more lateral displacement when reaching forwards (p < 0.001), and less lateral displacement when reaching sideways to the unaffected side (p = 0.01). Conclusion. COP displacement patterns in stroke subjects deviate more than those of healthy subjects in seated reaching tasks. The deviating COP displacement patterns are discussed as a possible dysfunction in the ability to make postural adjustments and learn an efficient movement pattern. Copyright © 2007 John Wiley & Sons, Ltd.     

Hypnotic depth and hypnotic susceptibility: A replicated finding

A sample of 398 Ss was tested in groups of from 8 to 20 people on the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor and E. Orne (1962). Retrospective depth reports for each of the 12 HGSHS:A items were taken in order to extend Tart's findings (1970, 1972) on susceptibility and depth. The Ss were tested over 2 successive years in samples of N = 220 and N = 178. Since results were almost identical for each year (thus constituting a replication), the data were pooled for this report.

A remarkable consistency in patterns of subjective depth across the 12 items of HGSHS:A was found, particularly noticeable in Items 7, 8, 9, and 10 for 4 susceptibility groups (high, high-medium, low-medium and low-susceptible Ss) which appeared to reflect differential item difficulties. In addition, all correlations between reported depth and HGSHS:A total scores were high and statistically significant. While the findings are in general accord with those of Tart (1970, 1972), further research is required in order to determine the underlying basis of depth reports, and the degree to which experimental reports of susceptibility and clinical reports of depth reflect similar experiential aspects of hypnosis.     

Postural neck pain: an investigation of habitual sitting posture, perception of 'good' posture and cervicothoracic kinaesthesia

Impairments of cervico-cephalic kinaesthesia and habitual forward head posture have been considered important in the aetiology of postural neck pain, yet these factors have not been specifically examined in a homogeneous clinical population. The objective of this study was to compare the habitual sitting posture (HSP), perception of good posture and postural repositioning error (PRE) of the cervico-thoracic (CT) spine in individuals with postural neck pain, with a matched group of asymptomatic subjects. Twenty-one subjects with postural neck pain and 22 asymptomatic control subjects were recruited into the study. An optical motion analysis system was used to measure the HSP and perceived ‘good’ sitting posture. PRE was measured over six trials where the subject attempted to replicate their self-selected ‘good’ posture. There was no difference between the groups in the HSP but significant differences were identified in the perception of ‘good’ posture. Posture repositioning error was higher for the head posture variables than for CT and shoulder girdle variables in both groups. However, there was no significant difference in posture repositioning error between groups for any of the posture measures. The findings suggest that individuals with postural neck pain may have a different perception of ‘good’ posture, but no significant difference in HSP or kinaesthetic sensibility compared with matched asymptomatic subjects.     

A comparison of the performance of hypnotic subjects and simulators on a variety of measures: A pilot study

Hypnotized Ss were compared with 2 simulator groups on 21 hypnotic procedures yielding a total of 60 measurements. Comparisons required 180 statistical analyses of which 7 attained statistical significance. An additional 14 analyses were considered to be suggestive although not statistically significant.     

Eye-roll and hypnotic susceptibility

Stager and Lundy (1985) found hypnotic hypermnesia without increased memory errors. The present study, an attempted partial replication of Stager and Lundy (1985), presented Ss with free recall and multiple choice questions about a short movie they had seen a week earlier. The experimental Ss, who were hypnotized, given hypermnesia suggestions, and retested, did not generally increase their accurate memory scores on posttest; the Stager and Lundy (1985) findings were thus not confirmed. An increase in memory scores did occur, however, but only with high hypnotizable Ss, whether they were hypnotized or not, and only with multiple choice questions. The high hypnotizable Ss had the greatest increase in inaccurate memory scores on the free recall questions.     

A comparison of hypnotic and waking recall

This paper presents data from a programmatic series of studies that varied the range of conditions affecting potential increase of recall, memory distortions, and distortions of confidence during and following hypnosis. All the studies used a paradigm that exposed Ss to misleading information some time before memory was tested and applied procedures in the hypnotic setting to analyze memory performance in both recognition and free recall. Results from the program failed to demonstrate any increment in accurate memory due to hypnosis, and the accuracy of memory reports in hypnosis was at times significantly reduced. Further, hypnotic recall was distinctively distorted when false information was introduced after, rather than before hypnosis. Results were discussed in relation to the role hypnotic as opposed to contextual variables may play in explaining Ss' memory test performances, and some legal implications are drawn from the data.     

Attitudes toward hypnosis,self-predictions,and hypnotic susceptibility

Correlation of questionnaire results from a sample of 1326 students with hypnotic susceptibility scores of 340 of these later hypnotized showed (a) that those volunteering for hypnosis were more favorable in attitude than those who did not volunteer, (b) attitudes toward hypnosis were predictive of susceptibility for females, not for males, and (c) self-predictions yielded significant low positive correlations with actual susceptibility for both sexes. Other findings concern differences between those having prior experience with hypnosis and those without such experience.     

A. comparison of hypnotic susceptibility as assessed by diagnostic ratings and initial standardized test scores

In a nonrandom sample of 63 Ss, a correlation of .79 was found between Stanford Hypnotic Susceptibility Scale, Form A (SHSS:A) of Weitzenhoffer and Hilgard (1959) scores and diagnostic ratings of hypnotizability. This degree of correlation corresponds to an index of forecasting efficiency of 36.8%. Limitations on the interpretation of this finding both as a validity coefficient and as an indicant of the predictive value of SHSS: A are discussed.