Influence Of Low Back Pain Research Articles

Finger-Floor Distance Is Not a Valid Parameter for the Assessment of Lumbar Mobility

Low back pain (LBP) could be associated with a reduced lumbar mobility. For the evaluation of lumbar flexibility, parameters such as finger-floor distance (FFD) are historically established. However, the extent of the correlation of FFD to lumbar flexibility or other involved joint kinematics such as pelvic motion, as well as the influence of LBP, is not yet known. We conducted a prospective cross-sectional observation study with 523 participants included (167 with LBP > 12 weeks, 356 asymptomatic). LBP-participants were matched for sex, age, height, and body-mass-index with an asymptomatic control cohort, resulting in two cohorts with 120 participants each. The FFD in maximal trunk flexion was measured. The Epionics-SPINE measurement-system was used to evaluate the pelvic and lumbar Range-of-Flexion (RoF), and the correlation of FFD to pelvic- and lumbar-RoF was evaluated. In an asymptomatic sub-cohort of 12 participants, we examined the individual correlation of FFD to pelvic- and lumbar-RoF under gradual trunk flexion. Participants with LBP showed a significantly reduced pelvic-RoF (p < 0.001) and lumbar-RoF (p < 0.001) as well as an increased FFD (p < 0.001) compared to the asymptomatic control cohort. Asymptomatic participants exhibited a weak correlation of FFD to pelvic-RoF and lumbar-RoF (r < 0.500). LBP patients revealed a moderate correlation of FFD to pelvic-RoF (male: p < 0.001, r = -0.653, female: p < 0.001, r = -0.649) and sex-dependent to lumbar-RoF (male: p < 0.001, r = -0.604, female: p = 0.012, r = -0.256). In the sub-cohort of 12 participants, gradual trunk flexion showed a strong correlation of FFD to pelvic-RoF (p < 0.001, r = -0.895) but a moderate correlation to lumbar-RoF (p < 0.001, r = -0.602). The differences in FFD in an individual patient, assuming consistent hip function, may be attributed partially to the differences in lumbar flexibility. However, the absolute values of FFD do not qualify as a measure for lumbar mobility. Rather, using validated non-invasive measurement devices should be considered.

Low back pain is associated with sleep disturbance: a 3-year longitudinal study after the Great East Japan Earthquake

BackgroundLow back pain and sleep disturbance are common health problems worldwide which are also commonly observed among people after natural disasters. These symptoms are well known to coexist, and recent reports have indicated that sleep disturbance is a risk factor for low back pain. However, the influence of low back pain on sleep disturbance has rarely been assessed; therefore, this study aimed to clarify the association of low back pain with sleep disturbance, especially focusing on the frequency of low back pain, using 3-year cohort data after the Great East Japan Earthquake.MethodsThis study used the data obtained from people living in the disaster-affected areas after the Great East Japan Earthquake (n = 2,097). Low back pain and sleep disturbance were assessed at 4, 5, 6, and 7 years after the disaster. The frequency of low back pain was defined as the number of low back pain episodes at and before the evaluation time point and categorized into five groups such as absence, 1, 2, 3, and 4 at the fourth time point and four groups such as absence, 1, 2, and 3 at the third time point. Multivariate logistic regression analyses were conducted to assess the association of low back pain with sleep disturbance.ResultsLow back pain was significantly associated with sleep disturbance, and the association was stronger in participants with more frequent low back pain (adjusted odds ratios [95% confidence intervals],1.46 [1.10–1.95] in “1”; 2.02 [1.49–2.74] in “2”; 2.38 [1.67–3.40] in “3”; and 4.08 [2.74–6.06] in “4” in the frequency of low back pain) (P for trend < 0.001). Furthermore, antecedent low back pain was significantly associated with new-onset sleep disturbance, and the association was robust in more frequent low back pain (adjusted odds ratios [95% confidence intervals],1.60 [1.05–2.44] in “1”; 1.96 [1.20–3.21] in “2”; and 2.17 [1.14–4.14] in “3” in the frequency of low back pain) (P for trend = 0.007).ConclusionOur study showed that low back pain is strongly associated with sleep disturbance. Attention should be paid to low back pain to prevent and treat sleep disturbance, especially focusing on chronicity of low back pain.

The effect of lumbopelvic region rotation relative flexibility on thorax–pelvis and pelvis–femur coordination during walking

BackgroundLumbopelvic region rotation relative flexibility (LRRF), which is defined as lumbopelvic region that is relatively less stiffness than the hip region, is associated with low back pain (LBP) symptoms. However, how LRRF is influenced by lumbopelvic region motion during walking is unclear. Research questionWhat is the influence of LBP and LRRF on coordination patterns of the thorax, pelvis, and femur during walking? MethodsThe presence of LRRF was determined based on whether the lumbopelvic rotation occurred in the first 50% of knee flexion or hip external rotation movement. Participants with LBP and LRRF were classified into the LBP group. Participants with LRRF but without LBP were classified into the early pelvis rotation (ROT) group, and those without LBP and relative flexibility were classified as controls. The thorax–pelvis coordination and pelvis–femur coordination during the stance cycles were calculated from the segmental angles obtained by three-dimensional motion analysis using a modified vector coding technique. ResultsIn the sagittal plane, the thorax–pelvis coordination of the LBP group showed more anti-phase patterns at both the early stance and midstance compared with controls and the ROT group. In the sagittal and horizontal planes, pelvis–femur coordination of the LBP and ROT groups showed more in-phase patterns during the early stance and midstance compared with controls. SignificanceRegardless of LBP, the presence of LRRF alters the intersegmental coordination during walking. In individuals with LRRF, stiffness of the hip may increase during walking. People who have LRRF without LBP may develop LBP in the future, and it is important for prevention to identify these differences in kinematics during walking.

The influence of low back pain on health – related quality of life and the impact of balneal treatment

Introduction. Low back pain has a direct and proportional impact on function and a general one on the quality of life. The present study aims to evaluate the functional impact of low back pain using specific self-assessment tools as indexes of appreciation and epidemiological correlations of potential risk factors involved. The conceptual model of our research is based on the importance of correlating symptoms with clinical assessment, using scales of pain, disability, quality of life, and determination of epidemiological correlations of these areas and the determined factors of the pathology. Material and method. The study group is made up of 106 cases with clinical diagnostic of low back pain, admitted from 28 September 2020 to 28 March 2021, at Balneal and Rehabilitation Sanatorium of Techirghiol. After performing anamnesis, general clinical examination, specific neuro-musculo-skeletal examination, the patients filled the surveys highlighting the impact of their low back pain on functionality and disability deriving from it. The survey included the Oswestry Disability Index, the Functional Independence Measure (FIM) instrument and the Visual analog scale (VAS) score evaluated at the moment of hospitalization and at discharge. Statistical analysis of data was carried out and correlations between variables resulting from study were highlighted. The study was conducted according to the norms of deontology and medical ethics. The authors declare no conflict of interest. Results and discussions. Lumbar pathology is common in patients who are hospitalized for a complex balneary-physical-kinetic treatment at Balneal and Rehabilitation Sanatorium of Techirghiol. About 80% of patients who have addressed to our unit in which the study was conducted, have presented low back pain. The majority of patients were females, representing 57,55% of the total number. Regarding the patients’ age, 58,5% of them were in the 50-70 years interval. The study reveals a major positive impact of our treatment on spinal symptomatology, an effect pointed out by the relevant statistical differences between the admittance and discharge VAS scores(p&lt;0.001). Reporting the investigated disability with the Oswestry questionnaire of painful lumbar syndrome, and functional evaluation scale (FIM) demonstrates the impact of this pathology on the patient's social life, once again emphasizing the special attention to be paid to axial pathology, both as curative treatment and the importance of prophylactic treatment. Statistical analysis of identified risk factors, reveals the importance of prophylaxis and patient’s education in this area. A strong and important statistical correlation was found between the Oswestry total score and the walking and standing items, and a moderate, but strong correlation with the other items. Regarding the sex life item, the correlation is existent, but at a modest level. Conclusions. The study reveals the importance of correlation of the data obtained from anamnesis, the general clinical examination and the specific examination neuromioarthrokinetic with assessment tools that determine the level of functional independence, the functional impact on social life in high-frequency pathologies treated in medical facilities that provide healthcare in the field of medical recovery. It is necessary to quantify the therapeutic results obtained, in order to assess the level of improvement in quality of life. Keywords: low back pain, balneal, functional indicators, quality of life,

Superficial lumbar muscle recruitment strategies to control the trunk with delayed-onset muscle soreness.

The lumbar region offers various muscle recruitment strategies to achieve a task goal under varying conditions. For instance, trunk movement control can be reorganized under the influence of low back pain. How such task-modulation is obtained is not fully understood. The objective of this study was to characterize superficial lumbar muscle recruitment strategies under the influence of delayed-onset muscle soreness (DOMS) during unexpected trunk perturbations. Healthy participants experienced a series of 15 sudden external perturbations with and without the influence of low back DOMS. During these perturbations, high-density surface electromyography was used to characterize recruitment strategies of superficial lumbar muscles, while kinematics sensors were used to characterize movements of the trunk. Lumbar muscle recruitment strategies, characterized by the amplitude of muscle activity amplitude, the latencies of the reflex activity and the spatial distribution of muscle activity, were compared across perturbations trials and with and without DOMS. An attenuation of lumbar muscle activity amplitude was observed across perturbation trials without DOMS, but not with DOMS. The spatial distribution of muscle activity was similar with and without DOMS. No significant changes in reflex activity latency and trunk flexion movement were observed. Following an unexpected trunk perturbation under DOMS effects, trunk movement are controlled using two different superficial lumbar muscles control strategies: keeping a constant level of their overall muscle activity and using a variable muscle recruitment pattern.

Influence of low back pain and its remission on motor abundance in a low-load lifting task

Having an abundance of motor solutions during movement may be advantageous for the health of musculoskeletal tissues, given greater load distribution between tissues. The aim of the present study was to understand whether motor abundance differs between people with and without low back pain (LBP) during a low-load lifting task. Motion capture with electromyography (EMG) assessment of 15 muscles was performed on 48 participants [healthy control (con) = 16, remission LBP (rLBP) = 16, current LBP (cLBP) = 16], during lifting. Non-negative matrix factorization and uncontrolled manifold analysis were performed to decompose inter-repetition variability in the temporal activity of muscle modes into goal equivalent (GEV) and non-goal equivalent (NGEV) variabilities in the control of the pelvis and trunk linear displacements. Motor abundance occurs when the ratio of GEV to NGEV exceeds zero. There were significant group differences in the temporal activity of muscle modes, such that both cLBP and rLBP individuals demonstrated greater activity of muscle modes that reflected lumbopelvic coactivation during the lifting phase compared to controls. For motor abundance, there were no significant differences between groups. Individuals with LBP, including those in remission, had similar overall motor abundance, but use different activation profiles of muscle modes than asymptomatic people during lifting.

Influence of low back pain in kick and ball velocity among adolescent soccer players with and without low back pain

The EDGES Collaboration has recently announced the detection of the 21-cm spectrum with an absorption profile centred at 78 megahertz, of which the depth is deeper than that expected by the standard cosmological paradigm. To enrich the heating process of baryons due to scattering with dark matter during dark ages, we in this Letter explore the possibility of extra heat transfer between dark sector compositions and their observational signatures on the 21-cm cosmological spectrum. By parameterizing interaction models of the dark Universe, we find that the observational constraint on the parameter space of dark matter can be slightly relaxed but the discrepancy with the commonly predicted parameter space of weakly interacting massive particles remains. Our analyses also reveal that the interaction between dark compositions may leave observational signatures on the 21-cm spectrum during dark ages and thus would become detectable in the forthcoming 21-cm cosmology.

No kidding: low back pain and type of container influence adolescents’ perception of load heaviness

The relationship between low back pain (LBP) and the lifting/carrying of loads is still a matter of great discussion. In teenagers, the weight of the school bag has been considered to play a pathogenic role in LBP but the relationship between the actual weight of the school bag and LBP symptoms does not seem to be a straightforward one. Numerous factors have been identified that influence the perception of weight. This study aimed to evaluate the influence of low back pain and the type of container on the perception of load heaviness by healthy teenagers. A convenience sample of 80 healthy teenage males (mean ± SD age 13.9 ± 2.1 years) was recruited from the members of two local sports clubs. The volunteers were evaluated during one of their training sessions. Information about a history of consequential LBP was gathered by questionnaire. Subjects were invited to estimate the weight of three bags (a typical school bag, a sports bag with the logo of a well-known brand, and a neutral bag) containing two different loads (total weights approximately 3 and 5 kg). Consequential LBP (i.e., LBP requiring medical attention and/or interfering with usual sports activities) was reported by 26.2% of them. The majority of the LBP episodes occurred ≥3 months before the tests. Overall, teenagers significantly (p ≤ 0.05) underestimated the weight of the sports bag compared with the school bag and the neutral bag. Compared with those with no LBP, subjects with a history of LBP overestimated the weight of the heavier load. Our results suggest that several subjective variables significantly influence the perception of load heaviness. Until we have a better understanding of the mechanical role of the backpack weight versus the perception of its weight in the aetiology of LBP, any recommendations about the schoolbag weight limit should be viewed with caution.

Influence of Low Back Pain and Psychological Factors on Presenteeism of Care Workers: a path analysis

〔目的〕介護職員におけるpresenteeismの発生頻度を調べ，かつ腰痛の程度および心理的因子がpresenteeismに与える影響を解析することとした．〔対象〕介護職員139名とした．〔方法〕presenteeismと腰痛の程度，心理的因子を対象者ごとに評価した．測定項目間の関係をモデル化し，パス解析にて，その適合度と測定項目間の関連性を検討した．〔結果〕対象者の66.9％にpresenteeismがみられた．修正モデルの適合性は十分に高かった．〔結語〕介護職員にとってpresenteeismは業務上の一般的な問題であること，心理的因子がこれに影響する因子として重要であることが確認された．

Influence of low back pain on total knee arthroplasty outcome

BackgroundPreoperative pain and functional status are strong determinants of postsurgical success in total knee arthroplasty. Patients suffering chronic pain from other coexistent musculoskeletal problems may respond differently postoperatively, with potentially poorer outcomes after surgery. The aim of the study was to determine the influence of low back pain on the outcome of total knee replacement surgery. MethodsAll patients completed Oxford Knee Scores (OKS), American Knee Society Scores (AKSS) and SF-12 (both physical and mental components). Patients were divided into those with (n=40) and without a documented history of low back pain (n=305). ResultsOKS, AKSS and SF-12 physical scores were significantly worse for patients with low back pain at 24months following surgery. The mental component of the SF-12 measure demonstrated a significant improvement in median mental health post-operatively for patients with no current history of low back pain. In contrast the group with low back pain showed no improvement in mental health scores post-operatively. ConclusionThis study demonstrates that symptomatic low back pain influences functional outcome after total knee arthroplasty surgery and that patients with low back pain show limited or no improvement in mental health post-operatively.Level of evidence II.

Postanesthesia Care Unit Imaging Is Unnecessary When Intraoperative Imaging Is Used During Anterior Cervical Decompression and Fusion Procedures

Retrospective case series. To characterize the clinical utility of imaging in the postanesthesia care unit (PACU) after anterior cervical decompression and fusion (ACDF) procedures. Two sets of imaging are often taken at the end of ACDF procedures: one intraoperatively and the other in the PACU. The latter may have low clinical utility. One hundred four patients who underwent ACDF procedures with anterior plate/screw constructs were identified. A panel assessed intraoperative and PACU series for adequacy of images to detect potential issues with placement of the surgical construct and for any actual visible issues with placement of the surgical construct. Intraoperative series were adequate to detect potential issues with construct placement for 78.8% of cases, whereas PACU series were adequate for only 58.7% of cases (significant difference, P<0.001). For both series, nearly all inadequacies were because of the shoulders obstructing the lateral view. Accordingly, cases with lower inferior operative levels were much more likely to have inadequate intraoperative and PACU series than cases with higher inferior operative levels (significant differences, P<0.001 for both). In no case was an issue with construct placement visible on a PACU series that was not also visible on an intraoperative series. This study demonstrates that PACU images are inferior to intraoperative images and offer little or no incremental clinical utility for detecting issues with surgical construct placement after ACDF procedures. PACU imaging after ACDF procedures might be discontinued to realize savings in time, cost, and radiation exposure.

Increase in Paravertebral Muscle Activity in Lumbar Kyphosis Patients by Surface Electromyography Compared With Lumbar Spinal Canal Stenosis Patients and Healthy Volunteers

Paravertebral muscle activity measurement by surface electromyography (EMG) in lumbar degenerative patients and healthy volunteers. Muscle activity was tested in the standing position, and the influence of low back pain and alignment of the lumbar spine was assessed in the patients with lumbar kyphosis (LDK) or canal stenosis. The number of kyphosis patients has increased as the population has grown older. Advanced kyphosis can cause difficulties in maintaining a standing position and affect daily living activities. The most direct cause is the atrophy of erector spinae muscles. The activity of these muscles has not yet been sufficiently evaluated and needs to be assessed objectively for the purpose of diagnosis and treatment. The subjects were kyphosis patients who were 60 years of age or older, age-matched lumbar spinal canal stenosis patients, and healthy volunteers. Muscular activity at the L1-L2 and the L4-L5 intervertebral areas was recorded by surface EMG in the resting standing position and also with a weight load held in the standing position. Muscle activity and muscle fatigue, and the association between the Visual Analogue Scale, the Japanese Orthopaedic Association score for low back pain, and muscle activity, were analyzed. Kyphosis patients had a greater muscle activity in the lower back in the resting standing position and more severe muscle fatigue at the upper lumbar spine in comparison with patients with lumbar spinal canal stenosis. There was no association between muscle activity and clinical findings in patients with LDK although. Our study revealed the constant activity of paravertebral muscles and the susceptibility to muscle fatigue in patients with LDK. The quantification of muscle activity by surface EMG may show the pathology of LDK, and the decrease in muscle activity in the standing position may be a potentially useful index for guiding treatment.

Assessing the association between low back pain, quality of life, and life events as reported by schoolchildren in a population-based study

Low back pain (LBP) is prevalent in teenagers but not necessarily detrimental to their quality of life (QoL). This population-based study evaluated a global QoL score and the association between LBP and life events and/or health problems affecting QoL. Schoolchildren were investigated in Fribourg-Switzerland and Barcelona-Spain. In addition to the KIDSCREEN, a health-related QoL questionnaire, two Numerical Rating Scales were used to assess QoL in general, and the influence of LBP on QoL. Open questions explored life events and health problems affecting QoL; responses were submitted to content analysis. Adolescents were stratified: Pain-free, Other pain (OP), isolated LBP (IsoLBP), LBP + other pains (LBP + OP), and LBP + whole-body pain (LBP + WBP). Between-group comparisons were performed using Chi-squared tests and ANOVA. Linear regression analysis was performed to assess between-group differences in the impact of LBP on QoL. Schoolchildren (1,470) (mean age = 15.05 years, 52.6% = boys) completed the questionnaire. LBP lasting >1 day in the last month was reported by 39.8% (N = 560): of them, 242 (43.2%) reported IsoLBP, 268 (47.9%) LBP + OP, and 50 (9.1%) LBP + WBP. QoL was lower in LBP + WBP (mean = 6.44 vs. LBP + OP = 7.8; IsoLBP = 7.6, OP = 7.96, Pain-free = 8.1; p < 0.001). There were 18.5% who reported health problems and 15.3% life events with a perceived impact on QoL. Prevalence was higher in LBP + WBP with >30% of this group identifying life events and/or health problems vs. 10-12% in PFree or IsoLBP groups (p < 0.001). IsoLBP affected QoL marginally (mean = 2.4 ± 2.2) compared to LBP + WBP (mean = 4.9 ± 2.4) (p < 0.001). LBP affected QoL marginally. These results stress the distinction between disease and common life experience. They also indicate the potential value of global QoL assessments in clinical settings.

The Influence of Low Back Pain on Care Workers' Health-related Quality of Life

The Influence of Low Back Pain on Care Workers' Health-related Quality of Life

Lombalgia e o equilíbrio corporal de atletas da seleção brasileira feminina de canoagem velocidade

Low back pain has been shown to interfere with body stability. In sports, the study of these relationships is important because the bouts may influence the results of training and competitions. High rates of injury to the lumbar region have been reported for elite female canoe paddlers. The objective of this study was to assess the influence of low back pain on body balance in female athletes of the Brazilian flatwater canoe team. Athletes with low back pain (in the last week) were compared to those without pain in the two-leg and single-leg stance, with the eyes open and closed, using an AccuSway Plus force platform (Advanced Mechanical Technology, Inc.). The variables analyzed were the amplitude of the pressure center in the anteroposterior direction (COPap) and medial-lateral direction (COPml). The results showed higher body ins-tability for athletes with low back pain. For COPml, no significant difference between the two groups was observed for only one condition (single-leg stance) (p = 0.901), and for COPap, no significant difference was observed for two conditions (p = 0.414 and p = 0.567), i.e., single-leg stance and eyes closed. In conclusion, low back pain was harmful to body balance in high-level female canoe paddlers.

Regional differences in lumbar spinal posture and the influence of low back pain

BackgroundSpinal posture is commonly a focus in the assessment and clinical management of low back pain (LBP) patients. However, the link between spinal posture and LBP is not fully understood. Recent evidence suggests that considering regional, rather than total lumbar spine posture is important. The purpose of this study was to determine; if there are regional differences in habitual lumbar spine posture and movement, and if these findings are influenced by LBP.MethodsOne hundred and seventy female undergraduate nursing students, with and without LBP, participated in this cross-sectional study. Lower lumbar (LLx), Upper lumbar (ULx) and total lumbar (TLx) spine angles were measured using an electromagnetic tracking system in static postures and across a range of functional tasks.ResultsRegional differences in lumbar posture and movement were found. Mean LLx posture did not correlate with ULx posture in sitting (r = 0.036, p = 0.638), but showed a moderate inverse correlation with ULx posture in usual standing (r = -0.505, p < 0.001). Regional differences in range of motion from reference postures in sitting and standing were evident. BMI accounted for regional differences found in all sitting and some standing measures. LBP was not associated with differences in regional lumbar spine angles or range of motion, with the exception of maximal backward bending range of motion (F = 5.18, p = 0.007).ConclusionThis study supports the concept of regional differences within the lumbar spine during common postures and movements. Global lumbar spine kinematics do not reflect regional lumbar spine kinematics, which has implications for interpretation of measures of spinal posture, motion and loading. BMI influenced regional lumbar posture and movement, possibly representing adaptation due to load.

Disorders in trunk rotation during walking in patients with low back pain: a dynamical systems approach

Objective. (1) To introduce an evaluation tool for the assessment of walking disorders in low back pain patients. (2) To investigate whether walking patterns in low back pain patients are different from those of control subjects. Design. Relative phase measures of movement coordination are applied in the assessment of trunk function in a small group of patients with non-specific low back pain and in control subjects. Background. Normal subjects change the coordination of pelvic and thoracic rotations from an in-phase to an out-of-phase pattern with increasing walking speed. Low back pain patients may have a reduced ability to counter rotate pelvis and thorax at higher walking speeds (from 1.0 m/s onwards) as a result of hyperstable coordination patterns. Methods. Six patients with non-specific low back pain and six healthy control subjects walked on a treadmill at comfortable walking speeds and during a systematic variation of the treadmill velocity. Coordination of arm and leg movements as well as of pelvic and thoracic rotations was analyzed using a relative phase algorithm. Results and Conclusions. The comfortable walking speed was reduced in the patient group. In contrast to the control subjects, four of the six patients were not able to establish an out-of-phase coordination pattern between thorax and pelvis at higher walking speeds. This coincided with an increased stability of movement coordination, indicating guarded behavior. In addition, an increased asymmetry between the phase-relations of left and right side of the body was found in some of the patients. Relevance The assessment of coordination between the movements of arms and legs and between rotations of pelvis and thorax during walking may be useful in the evaluation of low back pain. Further research could indicate whether this approach towards movement coordination allows for a classification of spine patients based on the influence of low back pain on gait.

The influence of low back pain on muscle activity and coordination during gait: a clinical and experimental study

Chronic low back pain (CLBP) is a major clinical problem with a substantial socio-economical impact. Today, diagnosis and therapy are insufficient, and knowledge concerning interaction between musculoskeletal pain and motor performance is lacking. Most studies in this field have been performed under static conditions which may not represent CLBP patients' daily-life routines. A standardized way to study the sensory-motor interaction under controlled motor performance is to induce experimental muscle pain by i.m. injection of hypertonic saline. The aim of the present controlled study was to analyze and compare electromyographic (EMG) activity of and coordination between lumbar muscles (8 paraspinal recordings) during gait in 10 patients with CLBP and in 10 volunteers exposed to experimental back muscle pain induced by bolus injection of 5% hypertonic saline. When the results are compared to sex- and age-matched controls, the CLBP patients showed significantly increased EMG activity in the swing phase; a phase where the lumbar muscles are normally silent. These changes correlated significantly to the intensity of the back pain. Similar EMG patterns were found in the experimental study together with a reduced peak EMG activity in the period during double stance where the back muscles are normally active. Generally, these changes were localized ipsilaterally to the site of pain induction. The clinical and experimental findings indicate that musculoskeletal pain modulates motor performance during gait probably via reflex pathways. Initially, these EMG changes may be interpreted as a functional adaptation to muscle pain, but the consequences of chronic altered muscle performance are not known. New possibilities to monitor and investigate altered motor performance may help to develop more rational therapies for CLBP patients.

EPIDEMIOLOGICAL STUDIES ON LOW BACK PAIN IN A SMALL RURAL COMMUNITY

Since 1964, the author has investigated frequency, cause and medical treatment of low back pain in a rural village of Gunma prefecture. Further he observed, from sociological viewpoint, influence of low back pain on zeal of rural workers for production, and made epibemiological study on it.The 1st report gives the preliminary approach to the question-collection of data from 1, 422 inhabitants of both sexes by enquete on frequency, mode of development, condition and cause of low back pain. The 2 nd report gives X-ray observations of 274 inhabitants of both sexes with low back pain and obstructions in their everyday lives in thrms of work day loss and medical treatments, which are used for the assessment of their disability. It was clarified by the preliminary approach given in the 1st report that a considerable large proportion, 23.5% mentioned “coldness” as the cause of low back pain, and that it developed in winter twice as often as in summer. In view of this local skin temperature was measured with a thermistor in order to seek relation between indivedual reactivity against exposure to coldness and incidence rate of low back pain. In addition, the subjects were exposed to artificial coldness to observe their reactions. These are the contents of the 5rd report. The results are summarized as follows : 1. The frequency of low back pain tended to increase with aging in both sexes. Actually suffering cases (those who have developed low back pain in the past 1 year) account for 15.3% and those who have its history, 42.0%. It needs much precaution to determine the frequency, since low back pain is variable in its nature, its manifestation is subjective, and its definition is not yet established.2. To the question 'when does the pain develop', the greatest number, 32%, responded, 'Always', followed by 19, 8% of 'Before going to bed', 13.4% of 'While walking', and 12% 'Abruptly'.3. As for the subjective cause and evoking factor 'not clear' represents 26. 1%, 'agricultural work' 25.3%, 'coldness' 25.5%, and 'trauma' relatively low 17. 7%.4. Disability owing to low back pain generally occurred in higher frequency in advanced ages and in females. High grade disability however, occurred also in thirties in both sexes. 5. X-ray observation revealed spondylosis deformans in 44. 8% and osteoporosis in 23. 7%. Discopathy such as herniation of nucleus pulposus was relatively infrequent, Bone abnormality was absent in 17.3% of males and 29.4% of females. The X-ray findings were not always in agreement with the symptoms.6. As for the duration of the pain, 'within I week' accounted for 1/3 for both males and females. Considerably large proportions, 45% of males and 35% of females, complained of the pain more than 30 days in total in a year.7. about 37% received medical treatment, and the remainder were either imperfectly treated or untreated.8. More females than males complained of coldness; especially remarkable are714%of female in thirties and forties and 51.0% in fifties, who complained of coldness. Low back pain occurred more frequently in those who complained of coldness without regard to sex.9. Experiment on exposure to coldness (examination for rise in skin temperature on exposure to artificial coldness). Restoration of skin temperature was slow in those with objective symptoms such as tender point, , back pain, myosclerosis and lasegue.10. In relatively younger subjects who were actually suffering low back pain, skin temperature (on the hip) was lower than in the normal by 0. 1°0. 4°C.In the village of the present survey, there were many with the socalled lumdago, which is. induced by overwork in agriculture or by coldness. In those of advanced age were observed also spondylosis deformans and osteoporosis which result from physiological aging accelerated by overwork which is postulated as the result of enlargement of occupational sphere.