Women at work despite ill health: diagnoses and pain before and after personnel support. A prospective study of hospital cleaners/home-help personnel with comparison groups.

The present study sought to elicit the diagnoses behind the pain conditions causing complaints by female hospital cleaners and home-help personnel who were working despite their symptoms. We also wished to describe the prevalence of musculoskeletal diagnoses and the intensity, frequency and location of pain, and changes in the clinical picture and pain after personnel supporting interventions. A prospective study was carried out with intervention groups and non-randomized comparison groups. The hospital cleaners intervention programme comprised occupational organizational measures, competence development, physical and psychosocial working environmental measures and individual and rehabilitation measures on both an individual and a group basis. The home-help programme comprised a 2-week stay at an orthopaedic rehabilitation unit, training of supervisors, comrade massage, purchase of training equipment and stress management. Myalgia/ tendinitis occurred in 61% of shoulder girdle elevators, 18% of rotator cuffs, 16% of dorsal neck muscles and 29% of hip muscles. There was musculoskeletal pain in the lower back in 28% of cases. Referred pain from a musculoskeletal focus occurred in about one-sixth to one-third of individuals with the diagnosis in question. Neurogenic pain occurred in 6% of cases. No fibromyalgia syndrome was found. One-third of individuals felt pain all the time or almost all the time. The mean rated perceived "worst pain" was 70 mm on a visual analogue scale of 1-100 mm. Comparisons between intervention and reference groups indicated that some improvement in the clinical picture can be attained using this kind of general support programme for employees.

Mobility, muscular strength and endurance in the cervical spine in Swedish Air Force pilots.

PURPOSE: Muscle strength, endurance and range of movement of the cervical spine in a group of Swedish Air Force jet pilots (AF) and in a reference group of conscripts doing their military service (RG) were compared. METHODS: We tested 30 (AF) 24-42 yr and 33 (RG) 19-22 yr. A questionnaire was used to document complaints. Maximum voluntary isometric muscle strength of the flexor and extensor muscles of the cervical spine and sub-maximum isometric endurance in the flexor and extensor muscles were measured. RESULTS: Eleven AF (37%) and four RG (12%) had experienced discomfort in the neck within the previous year. The pilots' flexor and extensor muscle strength (47 Nm and 65 Nm) was superior to that of the conscripts (36 Nm and 59 Nm) (p = 0.0001, p = < 0.05, respectively). However, the RG group had greater isometric endurance in the flexor muscles than AF (p = < 0.05) and greater neck rotation (p = <0.005). There was no difference between the two groups in the other variables. CONCLUSION: Differences between the groups with regard to muscle strength and endurance might depend on variations in work-related physical muscle strain, and/or differences in fiber composition in the muscles, which might be reflected by pilot selection procedures.

Health-related quality of life in women at work despite ill-health. A prospective, comparative study of hospital cleaners/home-help staff before and after staff support.

The aims of this prospective, non-randomized, comparative study were to elucidate how 99 female hospital cleaners and home-helps, at work despite ill-health, experienced their quality of life, and to study whether this was affected by a particular programme of staff support. The SF-36 questionnaire was used. This contains questions on physical, mental and social health status. Health status, i.e. experienced health, was assessed by the respondents themselves. Low quality of life relating to the dimensions bodily pain, general health perceptions and vitality proved to apply both to the hospital cleaners and the home-help staff, compared to a normal Swedish female population. No significant differences between the intervention group and the reference group were demonstrated among either the cleaners or the home-helps. Following the intervention/period of customary measures, experienced quality of life was somewhat changed in the groups compared with the normal Swedish female population. This may indicate a certain unspecific improvement in experienced quality of life in both the intervention groups and the reference groups.

Chimeric bovine respiratory syncytial virus with glycoprotein gene substitutions from human respiratory syncytial virus (HRSV): effects on host range and evaluation as a live-attenuated HRSV vaccine.

We recently developed a system for the generation of infectious bovine respiratory syncytial virus (BRSV) from cDNA. Here, we report the recovery of fully viable chimeric recombinant BRSVs (rBRSVs) that carry human respiratory syncytial virus (HRSV) glycoproteins in place of their BRSV counterparts, thus combining the replication machinery of BRSV with the major antigenic determinants of HRSV. A cDNA encoding the BRSV antigenome was modified so that the complete G and F genes, including the gene start and gene end signals, were replaced by their HRSV A2 counterparts. Alternatively, the BRSV F gene alone was replaced by that of HRSV Long. Each antigenomic cDNA directed the successful recovery of recombinant virus, yielding rBRSV/A2 and rBRSV/LongF, respectively. The HRSV G and F proteins or the HRSV F in combination with BRSV G were expressed efficiently in cells infected with the appropriate chimeric virus and were efficiently incorporated into recombinant virions. Whereas BRSV and HRSV grew more efficiently in bovine and human cells, respectively, the chimeric rBRSV/A2 exhibited intermediate growth characteristics in a human cell line and grew better than either parent in a bovine line. The cytopathology induced by the chimera more closely resembled that of BRSV. BRSV was confirmed to be highly restricted for replication in the respiratory tract of chimpanzees, a host that is highly permissive for HRSV. Interestingly, the rBRSV/A2 chimeric virus was somewhat more competent than BRSV for replication in chimpanzees but remained highly restricted compared to HRSV. This showed that the substitution of the G and F glycoproteins alone was not sufficient to induce efficient replication in chimpanzees. Thus, the F and G proteins contribute to the host range restriction of BRSV but are not the major determinants of this phenotype. Although rBRSV/A2 expresses the major neutralization and protective antigens of HRSV, chimpanzees infected with this chimeric virus were not significantly protected against subsequent challenge with wild-type HRSV. This suggests that the growth restriction of rBRSV/A2 was too great to provide adequate antigen expression and that the capacity of this chimeric vaccine candidate for replication in primates will need to be increased by the importation of additional HRSV genes.

Rehabilitative, psychiatric, functional and aesthetic problems in patients treated for burn injuries--a preliminary follow-up study.

Patients consecutively treated for burn injuries for four or more days during 1994 were examined one year after admission by a plastic surgeon, a specialist in rehabilitation medicine and a psychiatrist. Of thirty-nine such patients treated, two were dead, 11 did not present and six thought they had no remaining problems. Aesthetic and functional problems were present in 16 patients, in 11 reconstructive surgery given in one or more sessions was judged to have improved the condition. Of eighteen patients referred to a rehabilitation medicine specialist, 14 were assessed. Nine of these had functional impairments in the burn-injured body regions. A majority had functional impairments, persistent decrease in range of upper extremity motion, reduced muscle force, altered sensibility and itch. One patient suffered from pain. Three patients had occupational handicaps. Work disability occurred in two patients and further two were in need of vocational counselling due to the burn injury. In a subgroup of 11 patients four fulfilled criteria for one or more personality disorders, and two of these also suffered from major depression. Quality of life assessed with the SF-36 was lower than in a normal population. Some of the patients had psychiatric disease and personality disorders. Although rehabilitation started early in the acute phase of treatment, rehabilitation medicine function-increasing measures were needed in several cases. Individual rehabilitation programmes based on the patient's particular features and needs are recommended. The findings support the idea of a multidisciplinary approach for patients with burn injury and indicate that a subgroup of burn injury patients have functional impairments and/or disabilities which can probably be improved with reconstructive surgery and rehabilitation.

Assessment of jet pilots' upper trapezius load calibrated to maximal voluntary contraction and a standardized load.

Electromyographic (EMG) recording of the myoelectrical activity level in the trapezius muscle is often used as one method of assessing neck and shoulder muscle workload. To analyse how the normalization value influences interpretation of upper trapezius load during a work task, two different reference values for normalization were applied - one obtained during a maximum voluntary contraction (MVE) and the other during a standardized muscular load (RVE). Nine jet pilots (ages 30-48 yr) flew two sorties in a 37 Viggen aircraft using either of two types of head garment while 3-D acceleration and muscular activity were recorded. In each sortie twice in the programme a steep left turn at 5-6 +G(Z) was performed. The highest activity level (MVE) obtained during shoulder elevation combined with an isometric heavy resistance (maximum) against arm flexion/abduction was used as one normalization value. Before, between, and after the two flights, 15 s EMG recordings (RVE) during a dumbbell test in the same arm position were also taken. The muscular activity in the upper trapezius during a given task varied a great deal between individuals, but the reliability of the amplitude levels on different occasions during a work day was good, given the same electrode location and application. If muscular activity during a standardized loading force (e.g. dumbbell test) is used to normalize the recordings for workload assessments related to utilized muscular capacity, a subject with high muscular strength and comparatively low workload might in some situations be assessed as having the same workload as, or a higher load than a subject with less strength and a comparatively high workload. While normalization using a standardized force can be used to assess changes in workload, for assessing workload related to the individual's capacity recording the myoelectrical activity during maximal contraction is preferable.

Anterior chest support, muscular activity and subjective rating of exertion during microtome sectioning.

Seven females, six laboratory assistants, participated in the experimental part of the study. The level of muscular activity in different sitting work postures was recorded, using surface electrodes, as full-wave-rectified and low-pass filtered EMG, and normalised. The laboratory assistants also rated the degree of exertion in four different body regions during their ordinary microtome sectioning work, comparing the use of anterior chest support with the use of their usual chair with lumbar support. The use of anterior chest support reduced the muscular activity in the lumbar back muscles but increased it in the shoulder muscles. Perceived exertion in the neck, shoulders and thoracic back regions increased. Anterior chest support does not seem to solve the problem of neck- and-shoulder load-elicited pain during the work of preparing laboratory sections.

Work technique training for patients with chronic pain in neck, shoulder and arm. A questionnaire pilot study after a comprehensive exercise-oriented rehabilitation program.

Syftet med denna studie var att följa upp hur patienter såg på sin arbetsmiljö och arbetsteknik samt hur föreslagna arbetsplatsanpassningar hade genomförts efter deltagande i ett multimodalt intensivträningsinriktat rehabiliteringsprogram. Programmet inkluderade en väsentlig del av individuell ergonomisk analys, individuell ergonomisk rådgivning och specifik arbeetsteknikträning på arbetsterapiavdelningen. Patienterna hade kronisk muskuloskelettal smärta i armen. Efter rehabiliteringsprogrammet skickades ett frågeformulär till 181 patienter, varav 135 patienter (109 kvinnor och 26 män) (75%) svarade. Mer än halften av patienterna rapporterade att de oftere än en gång i veckan tänkte tillbaka på den individuella ergonomiska rådgivningen som gavs i samband med att videofilmen tagen på deras arbetsplats presenterades. Deras skattningar visade på en hög medvetandegrad när det gällde att la mikropauser under arbetet (dvs atl räta upp ryggen kombinerat med muskelavslappning), att arbeta med armarna nära kroppen och att lyfta bördor nära kroppen. Hälften av patienterna hade använt sig av möjligheten att ändra arbetsställning mer än en gång per timme. Resultatet indikerar att patienterna var medvetna om sin arbetsteknik efter deltagandet i rehabiliteringsprogrammet.

Isometric strength in flexors, abductors, and external rotators of the shoulder.

The aim of this study was to map the isometric shoulder muscle strength of 96 men and 90 women randomized from the population register of Stockholm citizens (reference groups), and of 83 male furniture removers and 89 female secretaries (aged 19-65 years, all four groups). Maximum isometric strength of the right-side shoulder flexors (90° joint angle), abductors, and external rotators (0°) was recorded with the subject sitting in a standardized position in an adjustable chair. Women had 43, 55, and 56% of the men's strength in the abductors, flexors, and external rotators respectively. Neither of the female test groups showed any change in maximum isometric strength with increasing age. Men from the reference group showed an age-related difference only in shoulder flexor strength, where the older men (45-65 years) had 89% of the younger men's (19-44 years) strength. The strength values of older furniture removers were 77-83% of the younger colleagues' values in all muscle groups tested. The muscular strength utilization ratio (MUR%) when holding the arm without external load at 90° shoulder flexion was 22-25 MUR% for the male groups and 34 MUR% for the female groups, which shows that the muscular load on the shoulder caused by the weight of the arm is of great importance.

Maximum neck extension strength and relative neck muscular load in different cervical spine positions.

The aim of this project was to study how the isometrical neck extensor strength varies at different joint angles in the sagittal plane in order to calculate what fractions of the maximum strength are used in sitting postures to counteract the load moment induced by the weight of the head and neck segments. Ten female subjects sat with the torso fixed in a special device. The resistive force during maximum neck extension was recorded with a strain gauge in four different positions of the lower cervical spine; extended, vertical, slightly flexed and much flexed. For each of these four positions the upper cervical spine was kept in three positions-flexed, neutral and extended. Moments of force about the bilateral motion axes of the atlanto-occipital (Occ-C1) joint and the C7-T1 motion segment were calculated. Moment arms were measured from video images. The maximum muscular moment for Occ-C1 did not vary systematically, either with different positions of the lower or upper cervical spine. The mean neck extensor strength for C7-T, was lowest in the extended lower cervical spine position. In the vertical, slightly flexed or much flexed position little or no variation in strength was seen. However, the fraction of the strength (% MUR) utilized to counteract the load moment induced by the weight of the head and neck in the different postures showed higher utilization ratios when the head-and-neck was flexed (about 10 and 17% MUR, respectively) than when it was kept in a vertical position (about 2% MUR). The results strongly indicate that the flexed cervical spine position produces higher muscular load than vertical, even when taking muscular strength into account, and should thus be avoided during prolonged sitting.

On neck muscle activity and load reduction in sitting postures. An electromyographic and biomechanical study with applications in ergonomics and rehabilitation.

In this study of the biomechanics and muscular function of the cervical spine, skilled women workers simulated standardized electromechanical assembly work in eight sitting postures. Normalized electromyography was used to quantify activity in neck-and-shoulder muscles. With the whole spine flexed, muscle activity in the cervical erector spinae, trapezius and thoracic erector spinae muscles was higher than when the whole spine was straight and vertical. The posture with the trunk slightly inclined backward and neck vertical gave the lowest activity levels. Flexed neck compared to vertical neck gave higher activity in the cervical erector spinae. Work with abducted arm gave high neck muscle activity. Work postures can thus be optimized to diminish neck muscle load. Two ergonomic acids were studied during the work cycle. Elbow support reduced the activity in the trapezius and thoracic erector spinae/rhomboids muscles in the posture with the whole spine flexed and in the posture with the whole spine vertical. Arm suspension gave mainly similar reduction in these postures, and also a reduction in the cervical erector spinae. In the position with the trunk slightly inclined backward, arm suspension gave a reduction in the trapezius. These findings indicate that arm support or arm suspension can be used to reduce neck muscle load. Three methodological studies related to neck muscle load and normalization were included. 1) Examination of the effect of different isometric maximum test contractions on neck muscles showed that all contractions activated all muscles studied, including those on the contralateral side, to some extent and at various levels. The highest frequency of attained maximum levels was: for neck extension, in cervical erector spinae; for cervical spinae lateral flexion, in splenius and levator scapulae; for arm abduction, in trapezius, and, for shoulder elevation and scapular retraction/elevation, in thoracic erector spinae/rhomboids. Proximal resistance gave higher activity than distal. 2) The relationship between EMG activity and muscular moment was studied in women during submaximal and maximum isometric neck extension. The relationship found was non-linear, with greater increase in activity at high moments in the posterior neck muscles studied. The slightly flexed cervical spine position induced a higher level of activity in erector spinae cervicalis than did the neutral position for a given relative muscular moment. 3) Muscular activity was related to cervical spine position during maximum isometric neck extension. Peak activity in the cervical erector spinae was found in the slightly flexed lower-cervical spine position.(ABSTRACT TRUNCATED AT 400 WORDS)

Activity levels during isometric test contractions of neck and shoulder muscles.

In order to analyse isometric muscle test contractions in the neck and shoulder region, an electromyographic (EMG) study of ten healthy females was undertaken. A series of 13 standardized isometric contractions with manual resistance was performed in the sitting position. Rectified time-averaged EMG was recorded, using surface electrodes. All tests activated all muscles studied to some extent and at various levels, but four different patterns of activation could be identified. Maximum level of activity was obtained: 1) in the cervical erector spinae muscles during neck extension, 2) in the splenius and levator scapulae muscles during lateral flexion of the cervical spine, 3) in the trapezius, pars descendens muscle during abduction of the arm in the plane of the scapula, 4) in the thoracic erector spinae/rhomboids muscles during shoulder elevation or scapular retraction/elevation.

E.m.g./moment relationships in neck muscles during isometric cervical spine extension.

The aim of the study was to describe the e.m.gJmuscular moment (torque) relationships for neck and shoulder muscles during cervical spine extension. Ten healthy women participated. Their average age was 25·6 years. The neck extension muscular moments exerted were measured isometrically in neutral and in flexed lower-cervical spine positions with a strain gauge connected to a sling around the back of the head. The moment about the bilateral axis of the C7 T1 spinal motion segment was calculated as the moment balancing the sum of the moment of the sling resistance force and the moment caused by the gravity forces of the head and neck. Video images were analysed for moment arm length measurements. Simultaneously with the force recording, the e.m.g. activity was recorded through surface electrodes applied unilaterally at six locations in the neck and shoulder region. The rectified low-pass filtered e.m.g. signals were normalized against the highest activity level obtained during a series of standardized isometric test contractions. The results show that a non-linear e.m.g./moment relationship exists in axial musculature of the cervical spine, with a slightly higher increase in e.m.g. levels at high muscular moment values.

Cervical spine position versus e.m.g. activity in neck muscles during maximum isometric neck extension.

The aim of the study was to describe the relationships between cervical spine positions and neck muscle activity during maximum isometric neck extension. Ten healthy women participated (mean age 25·6 years). Maximum isometric neck extensions were performed in 12 different neck positions with resistance applied againstthe back of the head. Surface e.m.g. was recorded from posterior neck muscles at six locations. The e.m.g. signals were rectified, low-pass filtered and normalized. The position of the upper cervical spine did not influence the e.m.g. levels, whereas the lower cervical spine positions did. The e.m.g. levels, in the cervical erector spinae/trapezius were higher in the slightly flexed lower cervical spine position than in the neutral (despite an approximately similar magnitude of muscular moment developed), when the upper cervical spine was in the neutral position. However, when the lower cervical spine was much flexed the e.m.g. level was about the same as that of the neutral lower cervical spine position (with upper cervical spine neutral). The e.m.g. levels of the splenius and the thoracic erector spinae/rhomboids varied in a similar way, but less pronouncedly. These findings are of interest for the method of normalization of e.m.g,. e.g. in studies of work postures and/or movements.

Effects of arm support or suspension on neck and shoulder muscle activity during sedentary work.

The aim of this study was to evaluate the effects on the levels on neck and shoulder muscular activity of ergonomic aids used to support or suspend the arm in different sitting postures, both with and without movement of the arm-hand. Ten skilled women workers performed a standardized simulated work cycle similar to assembling printed circuit boards, in different sitting postures with and without ergonomic aids. The elbow was supported by a loosely-mounted, padded plate. For suspension, a new device, the K-block, was used giving an adjustable, constant suspending force. Full-wave rectified, low-pass filtered, time-averaged and normalized EMG was used. Surface electrodes were applied over six neck and shoulder muscles. The results show that a reduction in the level of activity in neck and shoulder muscles can be obtained with either aid. The reduction, whether caused by suspension or support of the arm, was related to the sitting posture. Elbow support might be more efficient than arm suspension in a sitting posture with the whole spine flexed, while arm suspension might be more efficient when the trunk is inclined slightly backward. Elbow support and, particularly, arm suspension may thus be recommended as technical aids in sedentary assembly work for patients with easily elicited cervical spine and/or shoulder pain. It is also suggested that arm suspension may be used to improve ergonomic conditions at workplaces.

Influence of sitting postures on neck and shoulder e.m.g. during arm-hand work movements.

The aim of the study was to analyze the effect of different sitting postures on the level of activity in some neck and shoulder muscles in a standardized work cycle involving movement of the arm/hand. Ten experienced female workers volunteered in a laboratory study. Full-wave rectified, low-pass filtered, time-averaged and normalized e.m.g. was used. Surface electrodes were applied unilaterally at six locations. The course of the level of muscle activity during the standardized work cycle is presented. There was a tendency to higher level of activity when the arm/hand was moving along the high part of the work object compared to along the low part. The level of activity during the standardized work movement with the arm/hand was significantly influenced by the sitting postures chosen. The highest activity levels were found in the posture with the whole spine flexed. A marked reduction of the level of activity was obtained when a posture with the thoraco-lumbar spine slightly inclined backward was used.