Biomedical subjects

B Gerdle

Publications and source records attributed to B Gerdle.

At least 19 recordsLinked to original sources

PubMed2005

Women with fibromyalgia: work and rehabilitation.

PURPOSE: To explore disability in women with fibromyalgia with a focus on their work situation. METHOD: Review of literature on work status of women with fibromyalgia. RESULTS: Major differences exist between studies in reported disability and in the percentages of women working. Limitations caused by pain, fatigue, decreased muscle strength, and endurance influence work capacity. However, 34 - 77% of the women work. Individual adjustments in the work situation are reported. When the women find a level that matches their ability, they continue to work and find satisfaction in their work role. Many factors besides degree of impairment or disability influence whether clients with longstanding pain can remain in their work role or return to work after sickness leave. CONCLUSION: The total life situation, other commitments, type of work tasks, the ability to influence the work situation, and the physical and psychosocial work environment are important factors in determining whether a person can remain in a work role. More knowledge is needed about how to adjust work conditions for people with partial work ability to the benefit of society and the individual.

Adolescent↗

PubMed2005

Non-invasive monitoring of muscle blood perfusion by photoplethysmography: evaluation of a new application.

AIM: To evaluate a specially developed photoplethysmographic (PPG) technique, using green and near-infrared light sources, for simultaneous non-invasive monitoring of skin and muscle perfusion. METHODS: Evaluation was based on assessments of changes in blood perfusion to various provocations, such as post-exercise hyperaemia and hyperaemia following the application of liniment. The deep penetrating feature of PPG was investigated by measurement of optical radiation inside the muscle. Simultaneous measurements using ultrasound Doppler and the new PPG application were performed to elucidate differences between the two methods. Specific problems related to the influence of skin temperature on blood flow were highlightened, as well. RESULTS: Following static and dynamic contractions an immediate increase in muscle perfusion was shown, without increase in skin perfusion. Liniment application to the skin induced a rapid increase in skin perfusion, but not in muscle. Both similarities and differences in blood flow measured by Ultrasound Doppler and PPG were demonstrated. The radiant power measured inside the muscle, by use of an optical fibre, showed that the near-infrared light penetrates down to the vascular depth inside the muscle. CONCLUSIONS: The results of this study indicate the potentiality of the method for non-invasive measurement of local muscle perfusion, although some considerations still have to be accounted for, such as influence of temperature on blood perfusion.

Adult↗

PubMed2004

Shoulder pain and its consequences in paraplegic spinal cord-injured, wheelchair users.

STUDY DESIGN: Cross-sectional. OBJECTIVES: To describe the consequences of shoulder pain on activity and participation in spinal cord-injured paraplegic wheelchair users. To describe the prevalence and type of shoulder pain. SETTING: Two spinal cord injury (SCI) centres in Sweden. METHODS: All subjects with paraplegia due to an SCI of more than 1 year living in the counties of Uppsala and Linköping, Sweden were contacted by mail and asked to fill in a questionnaire (89 subjects). Those of the responding 56 subjects with current shoulder pain were asked to participate in further examination and interviews. A physiotherapist examined 13 subjects with shoulder pain in order to describe type and site of impairment. To describe consequences of shoulder pain on activity and participation, the Constant Murley Scale (CMS), the Wheelchair Users Shoulder Pain Index (WUSPI) the Klein & Bell adl-index and the Canadian Occupational Performance Measure (COPM) were used. RESULTS: Out of all respondents, 21 had shoulder pain (37.5%). Data from 13 of those subjects were used in the description of type and consequences of shoulder pain. Findings of muscular atrophy, pain, impingement and tendinits were described. We found no difference in ADL-performance with, respectively without, shoulder pain (P=0.08) using the Klein & Bell adl-index. No correlation was found between the various descriptions of impairment, activity limitations and participation restriction (P>0.08). All together 52 problems with occupational performance due to shoulder pain were identified using the COPM. Of these, 54% were related to self-care activities. CONCLUSION: The consequences of shoulder pain in paraplegic wheelchair users are mostly related to wheelchair activities. Since the wheelchair use itself presumably cause shoulder problems, this will become a vicious circle. More research is needed in order to reduce shoulder problems in wheelchair users.

Adult↗

PubMed2003

Test-retest reliability of EMG and peak torque during repetitive maximum concentric knee extensions.

The aim of this study was to investigate the reliability of peak torque and surface electromyography (EMG) variable's root mean square (RMS) and mean frequency (MNF) during an endurance test consisting of repetitive maximum concentric knee extensions. Muscle fatigue has been quantified in several ways, and in isokinetic testing it is based on a set of repetitive contractions. To assess test-retest reliability, two sets of 100 dynamic maximum concentric knee extensions were performed using an isokinetic dynamometer. The two series were separated by 7-8 days. The subjects relaxed during the passive flexion phase. Twenty (10 men and 10 women) clinically healthy subjects volunteered. Peak torque and EMG from rectus femoris, vastus medialis, vastus lateralis and biceps femoris were recorded. RMS and MNF were calculated from the EMG signal. The reliability was calculated with intraclass correlation coefficient ICC (1.1) and standard error of measurements (SEM). The reliability of peak torque was good (ICC=0.93) and SEM showed low values. ICC was good for absolute RMS of rectus femoris (ICC>/=0.80), vastus medialis (ICC>/=0.88) and vastus lateralis (ICC>/=0.82) and MNF of rectus femoris (ICC>/=0.82) and vastus medialis (ICC>/=0.83). Peak torque, and MNF and RMS of rectus femoris and vastus medialis are reliable variables obtained from an isokinetic endurance test of the knee extensors.

Adult↗

PubMed2003

An estimation of the influence of force decrease on the mean power spectral frequency shift of the EMG during repetitive maximum dynamic knee extensions.

Frequency analysis of myoelectric (ME) signals, using the mean power spectral frequency (MNF), has been widely used to characterize peripheral muscle fatigue during isometric contractions assuming constant force. However, during repetitive isokinetic contractions performed with maximum effort, output (force or torque) will decrease markedly during the initial 40-60 contractions, followed by a phase with little or no change. MNF shows a similar pattern. In situations where there exist a significant relationship between MNF and output, part of the decrease in MNF may per se be related to the decrease in force during dynamic contractions. This study estimated force effects on the MNF shifts during repetitive dynamic knee extensions. Twenty healthy volunteers participated in the study and both surface ME signals (from the right vastus lateralis, vastus medialis, and rectus femoris muscles) and the biomechanical signals (force, position, and velocity) of an isokinetic dynamometer were measured. Two tests were performed: (i) 100 repetitive maximum isokinetic contractions of the right knee extensors, and (ii) five gradually increasing static knee extensions before and after (i). The corresponding ME signal time-frequency representations were calculated using the continuous wavelet transform. Compensation of the MNF variables of the repetitive contractions was performed with respect to the individual MNF-force relation based on an average of five gradually increasing contractions. Whether or not compensation was necessary was based on the shape of the MNF-force relationship. A significant compensation of the MNF was found for the repetitive isokinetic contractions. In conclusion, when investigating maximum dynamic contractions, decreases in MNF can be due to mechanisms similar to those found during sustained static contractions (force-independent component of fatigue) and in some subjects due to a direct effect of the change in force (force-dependent component of fatigue). In order to compare MNF shifts during sustained static and repetitive dynamic contractions it is necessary to estimate the force-dependent component of fatigue of dynamic contractions. Our results are preliminary and have to be confirmed in larger experiments using single dynamic contractions when determining the MNF-force relationship of the unfatigued situation.

Adolescent↗

PubMed2001

Wheelchair seating intervention. Results from a client-centred approach.

PURPOSE: The aim of this study was to analyse the effects of wheelchair intervention from a client-centred perspective. METHOD: Results from 38 consecutive active wheelchair users visiting the wheelchair-seating department at the University Hospital in Linköping, Sweden, were analysed and described. All clients had defined problems related to wheelchair seating. Back pain was estimated before intervention and at follow-up, using a Visual Analogue Scale. The effect of intervention on different aspects of wheelchair functionality, seating and occupational performance was estimated by the clients at follow-up. RESULTS: Two initial main problem areas were identified among the group; seating discomfort (87%) and back pain (63%). Back pain was significantly reduced at follow-up (p<0.001). Problems initially defined by the clients, e.g. seating discomfort, were affected positively, in 79% of all clients, as estimated by the clients at follow-up. No significant correlation was found between the initial cause of intervention or the highest ranked wheelchair functionality aspect and final acceptance of intervention. CONCLUSIONS: The results from this study confirm the possibility of reducing, or even eliminating, common secondary problems such as back pain and discomfort, related to wheelchair seating by individually adjusted measures. Further research and development in this field is both necessary and cost-effective.

Adult↗

PubMed2001

Early interdisciplinary rehabilitation programme for whiplash associated disorders.

PURPOSE: To assess the clinical outcomes of a multidisciplinary rehabilitation programme for early intervention of chronic whiplash associated disorders (WAD). The primary aim of the programme was to increase levels of activity and independence in patients suffering WAD. METHODS: Ninety subjects with purported chronic symptoms associated with whiplash associated disorder (WAD) were referred to a multi-centre multi-modal 5- and 8-week rehabilitation programme in 1997-1998, during which prospective and retrospective functional and psychological evaluations were conducted, the follow-up was to 6 months. RESULTS: Subjects indicated they were satisfied with the programme. Retrospective evaluation indicated increased ability to cope with and control pain and, to some extent, psychological aspects. The pain intensity in the neck and upper back were significantly decreased at 6 months follow-up. However, for most of the functional and psychological markers, no significant changes were found. CONCLUSIONS: A multi-modal rehabilitation programme for the chronic suffering attributed to WAD had positive effects according to several aspects of the retrospective evaluations, but according to most of the aspects evaluated prospectively the programme does not appear to have significant benefits.

Adult↗

PubMed2001

Fibre type proportion and fibre size in trapezius muscle biopsies from cleaners with and without myalgia and its correlation with ragged red fibres, cytochrome-c-oxidase-negative fibres, biomechanical output, perception of fatigue, and surface electromyography during repetitive forward flexions.

In the literature enlarged/increased cross-sectional area (CSA) of type I muscle fibres has been reported as a morphological mark of work-related localised myalgia in the descending part of the trapezius muscle of women. These studies did not use enough subjects or lacked an adequate control group. The recording of surface electromyograms (EMG) is central to the research field of work-related myalgia. However, the influence of intrinsic muscle properties such as the effect of muscle fibre distribution upon surface EMG has to be better understood in order properly to evaluate this method as a possible diagnostic and preventive tool. This study had two aims. Firstly, it investigated the muscle fibre distribution and CSA in work-related myalgia in trapezius muscles. Secondly, the multivariate relationships among muscle morphology and histochemistry [ragged-red (RR) fibres, and cytochrome-c-oxidase-negative-fibre changes] EMG, perceived fatigue, and biomechanical output of shoulder flexions were analysed. The raw data have been presented in an earlier study. The participants in this study were 25 female cleaners with work-related myalgia of the trapezius muscle and 25 female cleaners not experiencing work-related myalgia of this muscle. The control group comprised 21 healthy female teachers who had not been exposed to highly repetitive work or static muscle work. Smaller CSA of type II fibres were found in cleaners compared to teachers. In this study the CSA of type I fibres of the trapezius muscles associated with myalgia were no greater than in muscles without myalgia. The prevalence of RR fibres together with age, fibre type proportions, CSA and working as a cleaner correlated with the ability to relax as recorded electromyographically. The relative mean frequency of the EMG of the trapezius muscle correlated with the prevalence of RR fibres, but it did not correlate with the proportions and CSA of different fibre types. Low biomechanical outputs and low signal amplitude increases of the EMG during the test were associated with high proportions of type -IIB fibres. The smaller CSA of type II fibres in cleaners might have reflected a different muscle activation pattern due to different occupational demands in cleaners than in teachers. Morphological or histopathological variables can influence the three EMG variables investigated.

Biomechanical Phenomena↗

PubMed2001

Mean frequency and signal amplitude of the surface EMG of the quadriceps muscles increase with increasing torque--a study using the continuous wavelet transform.

The continuous wavelet transform (CWT), a time-frequency method, was used when calculating mean frequency of the power spectrum (MNF) and signal amplitude (RMS) of the surface EMG to investigate their relationships to force during a gradually increasing knee extension (ramp). Based upon the CWT, MNF was redefined to include time dependence on the EMG signal frequency contents, the short-time MNF (STMNF). Surface EMG was recorded from vastus lateralis, rectus femoris and vastus medialis in 21 clinically healthy subjects during a brief, gradually increasing contraction up to 100% of a maximum voluntary contraction (MVC), with a duration of approximately 10 s. The relationships between the EMG variables and force using linear regression were determined for each subject. For vastus lateralis, we also investigated if certain aspects of the muscle morphology (i.e., proportions and areas of different fibre types) influenced the EMG-force relationship. For the majority of subjects (17-18 out of 21 subjects) there were significant positive correlations between STMNF and force in the three muscles. No sex differences were found in intercepts or regression coefficients of STMNF. The muscle morphology had a significant influence on the STMNF-force intercept and the regression coefficient. Positive and highly significant linear correlations between RMS and force were found for all subjects and all three muscles.In conclusion, time frequency methods can be applied when investigating EMG during brief contractions associated with non-stationarity. In a great majority of the subjects, and in the three muscles, significant linear force dependencies were found for STMNF. Thus, when evaluating muscle fatigue, e.g., in ergonomic situations, it is important to consider the force level as one factor that can influence the results. Morphological variables (fibre proportions and fibre areas) influenced the STMNF-force relationship in vastus lateralis.

Adult↗

PubMed2001

Quantitative sensory testing in fibromyalgia patients and in healthy subjects: identification of subgroups.

OBJECTIVE: To determine perception and pain thresholds in patients with fibromyalgia syndrome and in healthy controls, and to investigate whether patients with fibromyalgia syndrome can be grouped with respect to thermal hyperalgesia and whether these subgroups differ from healthy controls and in clinical appearance. DESIGN: The authors conducted a quasi-experimental clinical study. SUBJECTS: Twenty-nine women patients with fibromyalgia syndrome and 21 healthy pain-free age-matched women participated in the study. METHODS: Quantitative sensory testing using a Thermotest instrument was performed on the dorsum of the left hand. Sleep and pain intensity were rated using visual analog scales. RESULTS: Cold and heat pain but not perception thresholds differed significantly between patients with fibromyalgia syndrome and healthy subjects. Based on thermal pain thresholds, two subgroups could be identified in fibromyalgia syndrome using cluster analysis. CONCLUSION: Patients with fibromyalgia syndrome were subgrouped by quantitative sensory testing (i.e., thermal pain thresholds). Subgroups show clinical differences in pain intensities, number of tender points, and sleep quality. Cold pain threshold was especially linked to these clinical aspects.

Adult↗

PubMed2001

Prospective study of trigeminal sensibility after whiplash trauma.

Trigeminal sensory impairment is frequent in whiplash cases. The pathophysiology is unknown. The purpose of the present investigation was to prospectively study the trigeminal sensibility for temperature and vibration and to evaluate their relationship with the clinical symptoms. Thirty-four of 43 patients with whiplash injury were investigated through quantitative sensory tests with a mean of 6 weeks and 71 months after injury. Sensory disturbances over the trigeminal skin area persisted over the years ( r = 0.764. p < 0.000). At follow-up, a significant correlation ( r = 0.614, p < 0.000) was found between the sensory disturbances and the symptoms related to the central nervous system, whereas no significant relationship was found with the musculoskeletal symptoms. Trigeminal sensory impairment can either be explained by dysfunction in the central nervous system or by inhibitory mechanisms secondary to pain.

Adult↗

PubMed2001

Anterior tibial translation during different isokinetic quadriceps torque in anterior cruciate ligament deficient and nonimpaired individuals.

STUDY DESIGN: Factorial quasi-experimental design. OBJECTIVES: To quantify the effect of different levels of isokinetic concentric and eccentric knee extensor torques on the anterior tibial translation in subjects with anterior cruciate ligament (ACL) deficiency. Electromyogram (EMG) activity of 4 leg muscles was recorded in order to detect any co-activation of extensors and flexors. BACKGROUND: The rehabilitation after an ACL injury is of importance for the functional outcome of the patient. In order to construct a rehabilitation program after that injury, it is important to understand the in vivo relationships between muscle force and tibial translation. METHODS AND MEASURES: Twelve patients with unilateral ACL injury and 11 uninjured volunteers performed 36 repetitions of a quadriceps contraction at different isokinetic concentric and eccentric torque levels, on a KinCom machine (60 degrees x s(-1)), with simultaneous recordings of tibial translation (CA-4000) and EMG activity from quadriceps and hamstrings muscles. Tibial translations and EMG levels were normalized to the maximum of each subject. RESULTS: The individual anterior tibial translation increased with increased quadriceps torque in a similar manner in both quadriceps contraction modes in all legs tested. During concentric mode, translation was similar in all groups, but during eccentric mode, the mean translation was 38% larger in the ACL injured knees. No quadriceps-hamstrings co-activation occurred in any test or group. CONCLUSIONS: An ACL deficient knee can limit the translation within a normal space during concentric muscle activity but not during eccentric activity. That limitation depends on other mechanisms than hamstrings co-activation.

Adolescent↗

PubMed2001

Chronic pain and difficulty in relaxing postural muscles in patients with fibromyalgia and chronic whiplash associated disorders.

OBJECTIVE: To investigate if muscle tension according to the surface electromyogram (EMG) of the shoulder flexors is increased in consecutive patients with fibromyalgia (FM) or chronic whiplash associated disorders (WAD). METHODS: A total of 59 consecutive patients with FM (n = 36) or chronic WAD (n = 23) performed 100 maximal isokinetic contractions combined with surface electromyography of the trapezius and infraspinatus. A randomized group of pain-free female (n = 27) subjects served as control group. Peak torque initially (Pti) and absolute and relative peak torque at endurance level (PTe, PTer) were registered as output variables, together with the EMG level of unnecessary muscle tension, i.e., the signal amplitude ratio (SAR). RESULTS: The patient groups had a higher level of unnecessary tension initially and at the endurance level. The patients had lower absolute output (PTi and PTe), but the relative levels (PTer) did not differ comparing all 3 groups. Subjects with FM had significantly higher body mass index (BMI) than the other groups. BMI did not influence the SAR but correlated positively with PTi. CONCLUSION: The results confirmed earlier findings that groups of patients with chronic pain have increased muscle tension and decreased output during dynamic activity compared to pain-free controls. However, the results indicated there is heterogeneity within groups of patients with the same chronic pain disorder and that not all patients with chronic pain have increased muscle tension.

Adult↗

PubMed2000

A pilot study of body awareness programs in the treatment of fibromyalgia syndrome.

OBJECTIVE: To compare in a pilot study the effect of two physical therapies, the Mensendieck system (MS) and body awareness therapy (BAT) according to Roxendal, in fibromyalgia patients and to investigate differences in effect between the two interventions. METHODS: Twenty female patients were randomized to either MS or BAT in a program lasting 20 weeks. Evaluations were tender point examination and questionnaires, including visual analog scales (pain intensity at worst site, muscular stiffness, evening fatigue, and global health), Fibromyalgia Impact Questionnaire (FIQ), Coping Strategies Questionnaire, Quality of Life Scales, Arthritis Self-Efficacy Scale (ASES), and disability before, immediately after, and at 6 and 18 months follow-up. RESULTS: The BAT group had improved global health at 18 months follow-up, but lower results than the MS group. The MS group had improved FIQ, ASES other symptoms, and pain at worst site at 18 months follow-up. CONCLUSION: In the present pilot study, MS was associated with more positive changes than BAT.

Adaptation, Psychological↗

PubMed2000

The influences of muscle fibre proportions and areas upon EMG during maximal dynamic knee extensions.

This study is an investigation of the relationship between muscle morphology and surface electromyographic (EMG) parameters [mean frequency of the power spectrum (MNF), signal amplitude (root mean square, RMS) and the signal amplitude ratio (SAR; i.e. the ratio between the RMS level during the passive part of the contraction cycle and the RMS level during the active part of the contraction cycle)] during 100 maximal dynamic knee extensions at 90 degrees. s(-1). Each contraction cycle comprised of 1 s of active knee extension and 1 s of passive knee flexion. The surface EMG was recorded from the vastus lateralis muscle. Twenty clinically healthy subjects participated in the study, and muscle biopsy samples of the vastus lateralis were obtained from 19 of those subjects. The relationships between muscle morphology and EMG were investigated at three stages of the test: initially, during the fatigue phase (initial 40 contractions), and at the endurance level (the final 50 contractions). Major findings on correlations are that SAR and MNF tended to correlate positively with the proportion of type 1 fibres, and RMS correlated positively with the proportion of type 2 muscle fibres. The muscle fibre areas showed little correlation with the EMG variables under investigation. The results of the present study showed that the three EMG variables of a dynamic endurance test that were investigated (RMS, MNF and SAR) were clearly correlated with the proportions of the different fibre types, but only to a small extent with fibre areas. These findings contradict some of the theoretical models of the EMG, especially for parameters in the frequency domain.

Adult↗

PubMed2000

Mechanical performance and electromyography during repeated maximal isokinetic shoulder forward flexions in female cleaners with and without myalgia of the trapezius muscle and in healthy controls.

This cross-sectional study aimed at investigating the influence of occupational exposure to static and highly repetitive work involving the neck and shoulder muscles, myalgia of and tender point in the trapezius muscle on biomechanical output, and electromyogram (EMG) variables (mean frequency MNF, signal amplitude and ability to relax) during maximal forward flexions of the shoulder muscles. Groups of 25 cleaners suffering from chronic myalgia of the trapezius muscle, 25 cleaners free from myalgia of the trapezius muscle and 21 teachers performed 150 forward flexions using an isokinetic dynamometer. Perception of fatigue was reported and surface EMG was recorded from four muscles during the endurance test. The cleaners were stronger than the teachers. Myalgia was associated with lower levels of endurance and a high degree of perceived fatigue. The ability to relax the trapezius muscle decreased with age and was even lower in cleaners with and without myalgia. Higher MNF of the deltoid muscle but not of the trapezius muscle was found in the group suffering from myalgia compared to the groups free from myalgia. This cross-sectional study indicated that myalgia of the trapezius muscle did not influence the strength but did influence the endurance of the forward flexor muscles of cleaners. The observed decrease in the ability to relax the trapezius muscle in cleaners compared to healthy teachers might be indicative of a future insufficiency in the muscle. Prospective studies are needed to define the significance of the results presented here.

Cross-Sectional Studies↗

PubMed2000

Lack of gender differences in the ability to relax between repetitive maximum isokinetic shoulder forward flexions: a population-based study among northern Swedes.

The aim of the present study was to analyse the effects of gender and age in a population-based sample of clinically healthy subjects on: (1) strength, endurance and perception of fatigue, (2) mean frequency (MNF) of the electromyogram (EMG), and (3) the ability to relax between active contractions (signal amplitude ratio; SAR) of the surface EMG of an isokinetic shoulder forward flexion test. With this aim we have analysed aspects of the validity of MNF as an indicator of fatigue, using peak torque as a criterion variable. The subjects were 27 men and 28 women (age range: 20-60 years), who were obtained by random sample from the official census lists (participation rate: 66%). The peak torque and surface EMG of two portions of the trapezius, deltoid and infraspinatus muscles were recorded throughout 100 repetitive maximal isokinetic shoulder forward flexions. No significant differences in the perception of fatigue and relative endurance levels of peak torque and work were found between males and females. Males were significantly stronger than females and, on average, females produced approximately 60% of the output of the males; 76% after normalisation for body mass. The men had significantly lower MNF endurance levels for three of the investigated muscles. When controlled for age and body mass, the men had a significantly higher MNF of the deltoid muscle than did the females. These differences were only found for the deltoid muscle. Significant correlations existed between the MNF of the four muscles and biomechanical output, indicating criterion validity for the MNF variable with respect to fatigue. There were no significant effects of gender or age on the ability to relax between repetitive contractions (SAR). The higher prevalence of musculoskeletal complaints of the neck-shoulder region in females cannot be explained by a higher intrinsic muscle tension. Age, gender, body mass index and biomechanical output can have significant effects upon MNF. These effects are important considerations in the interpretation of MNF, for instance in ergonomic situations.

Adult↗

PubMed2000

The prevalences of cytochrome c oxidase negative and superpositive fibres and ragged-red fibres in the trapezius muscle of female cleaners with and without myalgia and of female healthy controls.

The association of cytochrome c oxidase negative fibres (COX-negative) and ragged-red fibres (RR-fibres) with work related trapezius myalgia has been proposed. Hitherto studies have been small or without control groups. The aim of the present study was to investigate the prevalences of RR-fibres and COX-negative fibres in female cleaners with (n=25) and without (n=23) trapezius myalgia and in clinically healthy female teachers (n=21). The cleaners did mainly floor cleaning requiring monotonous loading on the trapezius muscle. A questionnaire covering background data and aspects of pain (prevalence, duration, intensity and influence on daily living) was answered. Biopsies were obtained from the trapezius muscle by an open surgical technique. The three groups did not differ in prevalence of COX-negative or COX-superpositive (i.e. type-I fibres with extremely strong brownish reaction in both the COX and SDH/COX stainings) fibres. The prevalence of COX-negative fibres was age dependent. Two subgroups of RR-fibres were present when stained for COX; COX-negative (73%) and COX-superpositive (26%) fibres. Forty-two percent of the COX-negative fibres were RR-fibres and 79% of the COX-superpositive were RR-fibres. A significantly (P=0.002) higher proportion of the COX-superpositive fibres in the cleaners were RR-fibres compared to the teachers. Multivariate regression analysis revealed that age, occupation as cleaner and a tender point in the trapezius were significantly associated with increased prevalences of RR-fibres; a cleaner with a tender point had a 4.35 higher prevalence of RR-fibres compared to a teacher without a tender point. No correlations between other pain related variables and prevalence of RR-fibres were noted. In conclusion, RR-fibres but not COX-negative or COX-superpositive fibres were correlated with cleaning work tasks and with a tender point in the trapezius.

Activities of Daily Living↗