Evaluating the international standards gap for the use of acupuncture needles by physiotherapists and chiropractors: A policy analysis.

BACKGROUND: Acupuncture needles have become an increasingly-popular treatment tool used by multiple health professions. However, the World Health Organization (WHO)'s 1999 training guidelines for acupuncture address only medical doctors and licensed acupuncturists, leaving a gap as to appropriate training standards for other professions. AIMS AND METHODS: With reference to an extensive document analysis, and interviews with seventeen acupuncture educators from across several professions in Ontario, Canada, this work uses a critical qualitative policy analytic approach to: a) present a comprehensive account of statutory training requirements for acupuncture-needling physiotherapists and chiropractors in the United States, Canada, and Australia; and b) evaluate competing stakeholder discourses pertaining to recent related controversies. RESULTS: A wide range of educational requirements are evident across the jurisdictions under study (most below the 200-hour WHO guideline for physicians); and there is considerable disagreement among stakeholders as to what constitutes sufficient training in various forms of acupuncture, including 'dry needling'. Organizations defending brief post-graduate training for needling physiotherapists and chiropractors are generally associated with these two professions, and contend that their 'dry needling' practices differ substantially from traditional acupuncture. Characterizing such brief training as insufficient, opportunistic and unsafe, and 'dry needling' as a subset of acupuncture practice, are the voices of all acupuncture educators interviewed, as well as professional organizations representing physicians, licensed acupuncturists, and some physiotherapists and chiropractors. DISCUSSION AND CONCLUSION: Critiquing claims on both sides of the debate, this work calls for the development of independent, international safety-geared training guidelines that explicitly address the recent, evidence-informed trend towards biomedicalized acupuncture needling. Findings also suggest a need for additional research regarding the current shift towards overlapping-rather than exclusive-health professional practice scopes in industrialized countries.

Prevalência de subluxações cervicais e torácicas com relação ao membro dominante superior em atletas amadores de voleibol / Prevalence of cervical and thoracic subluxations in relation to the dominant upper limb in amateur volleyball players

O voleibol exige um ótimo condicionamento físico, força, velocidade, agilidade e flexibilidade de seus participantes. Nele, a repetição de determinados tipos de movimentos e a sobrecarga de treinamento exigida produz um processo de adaptação orgânica do corpo que resulta, muitas vezes, em desequilíbrio muscular. Somado a isso, os gestos específicos e os erros na técnica de execução dos movimentos podem aumentar a prevalência de alterações posturais influenciando o aumento de possibilidades de lesões (JUNIOR, 2004). As alterações posturais, por sua vez, podem ocasionar distúrbios que afetam a coluna vertebral. Objetivo: o propósito do estudo foi detectar as principais subluxações - vertebrais cervicais e torácicas - por meio da análise das rotações do processo espinhoso de cada vértebra e lateralidade do atlas com o membro dominante superior, relacionando com as categorias e com a posição em quadra de atletas de Voleibol. Método: para tanto, realizou-se uma pesquisa descritiva com 145 atletas de categorias de base e adulta que treinam mais de dois dias por semana. Os atletas foram submetidos a uma avaliação quiroprática. Resultados e Discussão: verificou-se que as subluxações mais prevalentes foram das vértebras C1, C7, T4, T8 e T12. Observou-se que a musculatura e a articulação do ombro estão diretamente interligadas com as subluxações encontradas. Atletas ambidestros apresentaram menor percentagem de subluxações e maior equilíbrio rotacional dos processos espinhosos e da lateralidade do atlas. Os demais atletas apresentaram a lateralidade do atlas e as rotações do processo espinhoso das regiões cervical e torácica para o lado direito...

Volleyball requires a great physical fitness, strength, speed, agility and flexibility of its players. In it, the repetition of certain types of movements and the overload of training required may produces an organic process of adaptation of the body that often results in muscle imbalance. Added to this, the specific gestures and errors in technique of the movements may increase the prevalence of postural changes influencing the increased possibilities of injuries. Postural changes, inturn, can lead to disorders affecting the spine. Objective: the purpose of the study was to identify the main subluxations - cervical and thoracic - through the analysis of rotations of the spinous process of each vertebra and laterality of the atlas with the dominant upper limb, in what respect the categories and the position in court of volleyball athletes. Method: it was carried out a descriptive study of 145 athletes from youth teams and adult training more than two days per week. The athletes underwent a chiropractic evaluation. Results and Discussion: it was found that the most prevalent vertebral subluxation are C1, C7, T4, T8 and T12. It was noted that the muscles and the shoulder joint are directly interconnected with the subluxations found. Ambidextrous athletes showed lower percentage of subluxations and higher rotational equilibrium of the spinous processes and the laterality of the atlas. The other athletes showed the laterality of the atlas and the rotations of the spinous process of the cervical and thoracic regions to the right side...

The perspectives and practices of alberta chiropractors regarding the sale of health care products in chiropractic offices.

OBJECTIVE: The purpose of this study is to describe the practices and perspectives of doctors of chiropractic in Alberta, Canada, regarding the sale of health products. This practice is considered in terms of ethical principles and professional practice standards. METHODS: Chiropractic Web sites in Alberta were identified using the publically available Web site of the Alberta College and Association of Chiropractors. A random sample of chiropractors was drawn and mailed a brief 4-page survey and return envelope. There was a follow-up mail out to nonrespondents 3 weeks later. Practitioners provided responses regarding their personal and professional characteristics and their perspectives and practices regarding health product sales. RESULTS: A total of 265 responses were received (response rate, 51.2%). Most practitioners endorsed health product sales by chiropractors (95%), and most were engaged in the practice (89%). Orthotics (77%) and pillows (69%) were sold most often, followed by nutritional supplements (68%), hot/cold packs (68%), and vitamins (52%). Some respondents identified areas of potential ethical concern, including product safety and efficacy, professional influence on consumer product purchase, and potential conflict of interest. Codes of ethics and conduct offer some guidance to practitioners, but their awareness of standards varied. CONCLUSIONS: The chiropractic profession within Alberta condones product sales, and most of its membership engages in the practice. Individual members differ in their perspectives on this practice and in their awareness of the national code of ethics and conduct.

The impact of microbial surveys on disinfection protocols in a chiropractic college environment.

OBJECTIVE: A baseline microbial survey was conducted to identify the microbes present on the headpieces of chiropractic adjusting tables from across the Western States Chiropractic College, Portland, Ore, facilities. This included the instructional adjustive technique laboratories, the student health center, the campus outpatient clinic, and an off-site clinic. The objective of this study was to evaluate the effect of disinfection protocols over time at a chiropractic college. METHODS: Four samplings were done for a 12-month period. A total of 69 treatment tables were tested. Sampling was done directly to blood agar (5% sheep blood) plates. Data obtained from the clinic locations were analyzed using linear regression models. RESULTS: Identification of microbes by differential staining and biochemical analysis yielded a variety of gram-positive bacteria in all 4 surveys. The numbers of bacterial colonies decreased in the second survey after changes to disinfection protocols. The number of colonies continued to remain below baseline in the third and fourth surveys. Methicillin-resistant Staphylococcus aureus was found in the clinics in 3 of 4 surveys. Methicillin-resistant S aureus was not detected in the technique laboratories. CONCLUSIONS: Various microbes were identified on the headpieces of adjusting tables in the college instructional technique laboratories and college clinics. Changing the disinfection protocols reduced the number of bacteria found in the second survey. In addition, the third and fourth surveys showed fewer bacterial colonies than baseline, suggesting that compliance with disinfection protocols continued over time.

Hand hygiene and treatment table sanitizing in chiropractic teaching institutions: results of an education intervention to increase compliance.

OBJECTIVE: The purpose of this study was to test an educational intervention designed to increase hand and treatment table sanitizing on 3 chiropractic college campuses using a theory-based intervention. The second purpose is to see if an increase in observed hand hygiene would be noted as a result of the intervention. METHODS: Students at 3 campuses were surveyed, and their attitudes and practices of hand and table sanitizing were observed. The education intervention was developed using ecological theory of health promotion and involved educating staff and students along with a focus on modeling proper behaviors. The surveys were analyzed and generated frequencies. chi(2) analysis and logistic regression models were used to explore effects. RESULTS: The education campaign was associated with increases in desired behaviors regarding both hand hygiene and table sanitizing. Good hand hygiene practices increased 35% (odds ratio [OR], 1.35; 95% confidence interval [CI], 1.03-1.77), and observed practices increased more than 2-fold (OR, 2.6; 95% CI, 1.90-3.52). A 30% increase in table sanitizing was noted as well (OR, 1.30; 95% CI, 1.04-1.64). CONCLUSIONS: Educational interventions after a theory-based model can have an initial impact on increasing hand hygiene and table sanitizing. Further studies should look at a policy component as an effect modifier and whether long-term effects will be seen from such an intervention.

The role of chiropractic adjusting tables as reservoirs for microbial diseases.

BACKGROUND: Our goal was to enumerate the microbial flora on the headrest, armrest, and thoracic portion of chiropractic adjusting tables to determine the presence of pathogenic microorganisms and identify the potential for nosocomial transmission. METHODS: Defined portions of the headrest, armrest, and thoracoabdominal pieces from 9 chiropractic adjusting tables were randomly sampled using the ACT II culture transport system (Remel, Lenexa, KS). Samples were incubated using standard culture techniques for bacteriology and mycology that included 15 mL of heart infusion agar at 35 degrees C for 24 hours and 15 mL of Sabouraud dextrose agar at 30 degrees C up to 7 days. RESULTS: Identification of microorganisms by biochemical analysis yielded a wide variety of gram-positive (G+) and gram-negative (G-) cocci and bacilli as well as standard fungi. Many were of the genus Staphylococcus. Methicillin-resistant S. aureus (MRSA) isolates were recovered from 2 separate tables. CONCLUSION: This study supports a growing consensus that those outpatient facilities that do not adhere to strict infection control protocols may become ecological reservoirs of potentially harmful human pathogens.

Validation of the spin-T goniometer, a cervical range of motion device.

OBJECTIVE: To test the validity of the Spin-T goniometer for the assessment of cervical range of movement. METHODS: A linear regression analysis for paired neck movements using first a foam head model and then human subjects was performed to quantify the differences between the measurements obtained from the MotionStar, a movement-tracking device, and the Spin-T. A within-subject repeated measures design using simultaneous data acquisition was completed. RESULTS: The coefficient of determination (R2) for all planes of cervical range of motion for both model and human data sets was higher than 0.99. The regression equations for the model data showed no significant (P > .05) intercept for flexion-extension and lateral rotation. Human data showed statistically significant intercept for flexion-extension (mean, -0.52 degrees) and lateral flexion (mean, 0.81 degrees) at P < .05. CONCLUSION: This study quantifies the difference between the MotionStar and the Spin-T goniometer and documents the systematic error between the measures. Where the error reached statistical significance, the magnitude of the error was very small (< 1.5 degrees). The results of this study suggest that the Spin-T goniometer may be used as a valid measuring instrument for cervical range of movement.

Validity of the lateral gliding test as tool for the diagnosis of intervertebral joint dysfunction in the lower cervical spine.

OBJECTIVE: To determine if the lateral gliding test for the cervical spine is a valid clinical test compared with radiological assessment as a tool for the diagnosis of intervertebral joint dysfunctions in the lower cervical spine in patients presenting with mechanical neck pain. METHODS: Twenty-five patients with mechanical neck pain presenting with an asymmetry of at least 5 degrees between left and right cervical lateral flexion and diagnosed with an intervertebral joint dysfunction in the lower cervical spine based on the lateral gliding test were studied. Two anterior-posterior x-rays were performed on each patient at maximum end-range of right and left cervical lateral flexion. The intervertebral motion was compared between the hypomobile side and the contralateral side at the level diagnosed as hypomobile by the lateral gliding test. RESULTS: The asymmetry between left and right cervical lateral flexion motion was 7.64 degrees +/- 2.25 degrees (P = .001). Fourteen patients were diagnosed with intervertebral dysfunctions on the right side, whereas 11 patients showed cervical hypomobility on the left. Joint dysfunction at the C3 vertebra was the most prevalent (n = 16), followed by the dysfunction at the C4 vertebra (n = 9). The intervertebral radiological motion at the hypomobile side (mean 19.1, SD 2.1 mm) was 3.44 +/- 1.9 mm less than the intervertebral radiological motion at the contralateral side (mean 22.6, SD 2.5 mm) with P = .002. CONCLUSIONS: The lateral gliding test for the cervical spine was as good as a radiological assessment for the diagnosis of intervertebral dysfunctions in the lower cervical spine.

PulStar differential compliance spinal instrument: a randomized interexaminer and intraexaminer reliability study.

OBJECTIVE: To provide an entry-level, new technology reliability assessment of the PulStar computer-assisted, differential compliance spinal instrument. SUBJECTS: Eighteen college students (9 male and 9 female) were recruited by announcements and personal contacts. METHODS: Following approval of the consent process by the Institutional Review Board of Mississippi State University, a PulStar Function Recording and Analysis System (PulStarFRAS) device was evaluated for clinical reliability. Two examiners, blinded from data collection, used the instrument on individual subjects in random order (lying prone with their backs exposed) to administer light impulses (approximately equal to .9 J which produced a 3- to 4-lb force) at each segmental level throughout the cervical, dorsal, and lumbar spine using probe tips spaced 3 cm apart, straddling the spinous processes, while a computer recorded the findings (resistance on a scale of 0 to 25.5 lb force). Data were analyzed by Exploratory Data Analysis (EDA) with analysis of variance (ANOVA) testing and by use of the intraclass correlation coefficient (ICC). In addition, a mean test (ANOVA) was conducted to determine if a trend in variation occurred as a result of repeated light thrusts to the spine, independent of variance explained by different examiners. RESULTS: Using EDA analysis and ANOVA, intraexaminer reliability for the 2 practitioners was very high but not perfect. This was confirmed by ICC statistics demonstrating good to excellent reliability for both practitioners (0.89 for the experienced practitioner, 0.78 for the newly trained practitioner). Interexaminer reliability of PulStar was similarly very high but not perfect based on EDA/ANOVA analysis and good to excellent (ICC = 0.87). CONCLUSION: The PulStar mechanical adjusting device set to analysis mode appears to have good to excellent reliability when used by either an experienced or a novice (but trained) examiner. In addition, as a measure for resistance to a light thrust or spinal compliance, reliability was similarly good to excellent between the 2 doctors using the PulStar instrument.

Comparative analysis of low-back loading on chiropractors using various workstation table heights and performing various tasks.

BACKGROUND: There is epidemiologic evidence that chiropractors are a high-risk group for low-back disorders. However, to date there are no known biomechanical studies to determine whether their workstations may be a contributing factor. OBJECTIVE: To investigate whether chiropractors' workstation table height or the tasks they perform make them susceptible to low-back strain. As well as investigating low-back strain, a screening was performed to determine whether chiropractors' upper extremities were at risk for undue strain as workstation table height was varied. STUDY DESIGN: Experimental pilot study. SETTING: A university ergonomic laboratory. METHODS: An adjustable manipulation table was set at 3 different heights: 465 mm, 665 mm and 845 mm. Each of the 7 volunteer chiropractors were fitted with a triaxial electrogoniometer and were videotaped and photographed for analysis while performing spinal manipulation to the cervical, thoracic, and lumbar spine of a volunteer patient at each workstation table height. Two biomechanical models, one static and one dynamic, were used to record the dependent variables. A screening of various upper extremity variables was also performed with the static model. RESULTS: For the subjects under study, a significant difference was found for the variables maximum sagittal flexion, disk compression force, and ligament strain as table height was varied. For the lumbar and thoracic manipulation tasks, the medium table height (655 mm) was found to create the least low-back strain. For the cervical manipulation task, the high table height (845 mm) was found to be the least straining on the low-back. The low height table (465 mm) was the most straining for all tasks. Upper extremities were not significantly affected by changes to table height. Significant differences were found for the task performed for axial rotational velocity, disk compression force, ligament strain, maximum sagittal flexion, dominant (right) elbow moment, and dominant (right) shoulder moment variables. There was no significant interaction between table height and task performed. CONCLUSION: Workstation table height was found to have a significant effect on low-back load of subjects under study. The results of this study demonstrate an overall unacceptably high amount of sagittal flexion, ligament strain, and disk compression force on the chiropractor subjects in the tasks performed.

Electromyographic reflex responses to mechanical force, manually assisted spinal manipulative therapy.

STUDY DESIGN: Surface electromyographic reflex responses associated with mechanical force, manually assisted (MFMA) spinal manipulative therapy were analyzed in this prospective clinical investigation of 20 consecutive patients with low back pain. OBJECTIVES: To characterize and determine the magnitude of electromyographic reflex responses in human paraspinal muscles during high loading rate mechanical force, manually assisted spinal manipulative therapy of the thoracolumbar spine and sacroiliac joints. SUMMARY OF BACKGROUND DATA: Spinal manipulative therapy has been investigated for its effectiveness in the treatment of patients with low back pain, but its physiologic mechanisms are not well understood. Noteworthy is the fact that spinal manipulative therapy has been demonstrated to produce consistent reflex responses in the back musculature; however, no study has examined the extent of reflex responses in patients with low back pain. METHODS: Twenty patients (10 male and 10 female, mean age 43.0 years) underwent standard physical examination on presentation to an outpatient chiropractic clinic. After repeated isometric trunk extension strength tests, short duration (<5 msec), localized posteroanterior manipulative thrusts were delivered to the sacroiliac joints, and L5, L4, L2, T12, and T8 spinous processes and transverse processes. Surface, linear-enveloped electromyographic (sEMG) recordings were obtained from electrodes located bilaterally over the L5 and L3 erector spinae musculature. Force-time and sEMG time histories were recorded simultaneously to quantify the association between spinal manipulative therapy mechanical and electromyographic response. A total of 1600 sEMG recordings were analyzed from 20 spinal manipulative therapy treatments, and comparisons were made between segmental level, segmental contact point (spinous vs. transverse processes), and magnitude of the reflex response (peak-peak [p-p] ratio and relative mean sEMG). Positive sEMG responses were defined as >2.5 p-p baseline sEMG output (>3.5% relative mean sEMG output). SEMG threshold was further assessed for correlation of patient self-reported pain and disability. RESULTS: Consistent, but relatively localized, reflex responses occurred in response to the localized, brief duration MFMA thrusts delivered to the thoracolumbar spine and SI joints. The time to peak tension (sEMG magnitude) ranged from 50 to 200 msec, and the reflex response times ranged from 2 to 4 msec, the latter consistent with intraspinal conduction times. Overall, the 20 treatments produced systematic and significantly different L5 and L3 sEMG responses, particularly for thrusts delivered to the lumbosacral spine. Thrusts applied over the transverse processes produced more positive sEMG responses (25.4%) in comparison with thrusts applied over the spinous processes (20.6%). Left side thrusts and right side thrusts over the transverse processes elicited positive contralateral L5 and L3 sEMG responses. When the data were examined across both treatment level and electrode site (L5 or L3, L or R), 95% of patients showed positive sEMG response to MFMA thrusts. Patients with frequent to constant low back pain symptoms tended to have a more marked sEMG response in comparison with patients with occasional to intermittent low back pain. CONCLUSIONS: This is the first study demonstrating neuromuscular reflex responses associated with MFMA spinal manipulative therapy in patients with low back pain. Noteworthy was the finding that such mechanical stimulation of both the paraspinal musculature (transverse processes) and spinous processes produced consistent, generally localized sEMG responses. Identification of neuromuscular characteristics, together with a comprehensive assessment of patient clinical status, may provide for clarification of the significance of spinal manipulative therapy in eliciting putative conservative therapeutic benefits in patients with pain of musculoskeletal origin.

A new symmetry-based scoring method for posture assessment: evaluation of the effect of insoles with mineral derivatives.

BACKGROUND: There is a need for a validated rapid procedure for the evaluation of posture, defined as lateral balance/imbalance at the pelvic, shoulder, and neck levels. This would enable clinicians to determine the importance of symmetry in the pathophysiology of musculoskeletal disorders and to assess the efficacy of devices and treatments claiming to normalize or improve posture. In this investigation, the efficacy of such a device, a set of insoles with a hypothesized proprioceptive-like action, was evaluated through use of the described procedure. OBJECTIVES: To develop a new scoring system to evaluate body posture on the basis of symmetry and to use this scoring system to investigate the efficacy of insoles containing a combination of mineral derivatives designed to balance posture through a neurophysiological effect. METHODS: The posture score was based on the evaluation of 4 postural parameters: pelvic and shoulder lateral balance/imbalance, static shoulder rotation, and amplitude of head rotation. In the placebo-controlled study, 32 patients were tested in a double-blind fashion, either with placebo insoles or with insoles containing mineral derivatives. The same study was repeated in unblind conditions in 137 patients selected from 2 chiropractic clinics in an open-label protocol. STUDY DESIGNS: A crossover placebo-controlled, double-blind study and a multicenter, large-scale, open-label study in patients selected from chiropractic clinics. RESULTS: A basal postural evaluation in 137 patients revealed that no patient had a perfect symmetry-ie, a perfectly or nearly perfectly balanced posture. The insoles with mineral derivatives induced a highly significant and similar improvement in the postural score in both the crossover double-blind study (32 patients; 56.7% improvement) and the open-label study (137 patients; 60.7% improvement, P < 0.001). CONCLUSIONS: All patients tested and selected in chiropractic clinics exhibited asymmetries and postural imbalances according to the newly developed scoring method, and this method was successful in assessing the efficacy of insoles exerting a profound and immediate postural effect through a hypothesized neurophysiological mode of action.

Validation of the force and frequency characteristics of the activator adjusting instrument: effectiveness as a mechanical impedance measurement tool.

OBJECTIVE: To determine the dynamic force-time and force-frequency characteristics of the Activator Adjusting Instrument and to validate its effectiveness as a mechanical impedance measurement device; in addition, to refine or optimize the force-frequency characteristics of the Activator Adjusting Instrument to provide enhanced dynamic structural measurement reliability and accuracy. METHODS: An idealized test structure consisting of a rectangular steel beam with a static stiffness similar to that of the human thoracolumbar spine was used for validation of a method to determine the dynamic mechanical response of the spine. The Activator Adjusting Instrument equipped with a load cell and accelerometer was used to measure forces and accelerations during mechanical excitation of the steel beam. Driving point and transfer mechanical impedance and resonant frequency of the beam were determined by use of a frequency spectrum analysis for different force settings, stylus masses, and stylus tips. Results were compared with beam theory and transfer impedance measurements obtained by use of a commercial electronic PCB impact hammer. RESULTS: The Activator Adjusting Instrument imparted a very complex dynamic impact comprising an initial high force (116 to 140 N), short duration pulse (<0.1 ms) followed by several lower force (30 to 100 N), longer duration impulses (1 to 5 ms). The force profile was highly reproducible in terms of the peak impulse forces delivered to the beam structure (<8% variance). Spectrum analysis of the Activator Adjusting Instrument impulse indicated that the Activator Adjusting Instrument has a variable force spectrum and delivers its peak energy at a frequency of 20 Hz. Added masses and different durometer stylus tips had very little influence on the Activator Adjusting Instrument force spectrum. The resonant frequency of the beam was accurately predicted by both the Activator Adjusting Instrument and electronic PCB impact hammer, but variations in the magnitude of the driving point impedance at the resonant frequency were high (67%) compared with the transfer impedance measurements obtained with the electronic PCB impact hammer, which had a more uniform force spectrum and was more repeatable (<10% variation). The addition of a preload-control frame to the Activator Adjusting Instrument improved the characteristics of the force frequency spectrum and repeatability of the driving point impedance measurements. CONCLUSION: These findings indicate that the Activator Adjusting Instrument combined with an integral load cell and accelerometer was able to obtain an accurate description of a steel beam with readily identifiable geometric and dynamic mechanical properties. These findings support the rationale for using the device to assess the dynamic mechanical behavior of the vertebral column. Such information would be useful for SMT and may ultimately be used to evaluate the [corrected] biomechanical effectiveness of various manipulative, surgical, and rehabilitative spinal procedures.

The ability to reproduce the neutral zero position of the head.

OBJECTIVE: To determine how precisely asymptomatic subjects can reproduce a neutral zero position of the head. STUDY DESIGN: Repeated measures of the active cervical neutral zero position. SETTING: Institute of Medical Biology (Center of Biomechanics) at Odense University. PARTICIPANTS: Thirty-eight asymptomatic students from the University of Odense, male/female ratio 20:18 and mean age 24.3 years (range, 20 to 30 years). INTERVENTION: Measurements of the location of the neutral zero head position by use of the electrogoniometer CA-6000 Spine Motion Analyzer. Each subject's neutral zero position with eyes closed was measured 3 times. The device gives the localization of the neutral zero as coordinates in 3 dimensions (x, v, z) corresponding to the 3 motion planes. RESULTS: The mean difference from neutral zero in 3 motion planes was found to be 2.7 degrees in the sagittal plane, 1.0 degree in the horizontal plane, and 0.65 degree in the frontal plane. CONCLUSION: We found that young adult asymptomatic subjects are very good at reproducing the neutral zero position of the head. This suggests the existence of some advanced neurologic control mechanisms.

The effects of high and low loading forces on measured values of lumbar stiffness.

OBJECTIVE: One explanation for the poor reliability of manual judgments of posteroanterior (PA) stiffness may be that if manual therapists use different forces when testing, different stiffness is perceived. This study was conducted to examine measurements of lumbar PA stiffness obtained using a device programmed to generate different loading forces. SUBJECTS: Twenty-five subjects with no history of low back pain and a mean age of 23.5 yr were measured. METHODS: Measures of lumbar PA stiffness were obtained using a mechanical device that applied a testing force of 200 N to the skin overlying the L3 spinous process. Six stiffness coefficients were determined from the force/displacement curve obtained from each subject by performing linear regressions from 30-80 N, 30-150 N, 30-200 N, and from 30-83.3 N, 83.3-136.7 N, and 136.7-200 N. Intraclass correlation coefficients and repeated measures analysis of variance were used to analyze the data. RESULTS: Although moderate reliability [ICC 2,1 = 0.67] was found for stiffness measures arising from increasingly wide force-interval regressions (30-80 N, 30-150 N, 300-200 N), poor reliability [ICC (2,1) = 0.39] was found for stiffness measures arising from same-width, higher force regressions (30-83.3 N, 83-137 N, 137-200 N). In both cases there were significant differences between the obtained K stiffness values corresponding to different force intervals. CONCLUSION: These results show that if therapists push harder, different stiffnesses will be felt. Studies using instrumental measurement of spinal stiffness to obtain 'K' values should report the force intervals used. Also, revised protocols for manually judging PA stiffness should ensure that stiffness is assessed by sampling specified force intervals rather than the raters determining their own force limits.