Jon Ingulf Medbø

Effect of acupuncture treatment on chronic neck and shoulder pain in sedentary female workers: a 6-month and 3-year follow-up study

&NA; The study was carried out to examine whether acupuncture treatment can reduce chronic pain in the neck and shoulders and related headache, and also to examine whether possible effects are long‐lasting. Therefore, 24 female office workers (47±9 years old, mean±SD) who had had neck and shoulder pain for 12±9 years were randomly assigned to a test group (TG) or a control group (CG). Acupuncture was applied 10 times during 3–4 weeks either at presumed anti‐pain acupoints (TG) or at placebo‐points (CG). A physician measured the pain threshold (PPT) in the neck and shoulder regions with algometry before the first treatment, and after the last one and six months after the treatments. Questionnaires on muscle pain and headache were answered at the same occasions and again 3 years after the last treatment. The intensity and frequency of pain fell more for TG than for CG (Pb≤0.04) during the treatment period. Three years after the treatments TG still reported less pain than before the treatments (Pw<0.001), contrary to what CG did (Pb<0.04). The degree of headache fell during the treatment period for both groups, but more for TG than for CG (Pb=0.02). Three years after the treatments the effect still lasted for TG (Pw<0.001) while the degree of headache for CG was back to the pre‐treatment level (Pb<0.001). PPT of some muscles rose during the treatments for TG and remained higher 6 months after the treatments (Pw<0.05), which contrasts the situation for CG. Adequate acupuncture treatment may reduce chronic pain in the neck and shoulders and related headache. The effect lasted for 3 years.

Examination of the Metamax I and II oxygen analysers during exercise studies in the laboratory

The performance of the Metamax I and the Metamax II portable analysers for measuring the O 2 uptake has been examined during exercise. Healthy subjects ran on the treadmill or bicycled on ergometers while the O 2 uptake was measured by the Metamaxes and also by the Douglas bag technique or the Vmax 29 instrument. In the first series of experiments, O 2 uptake was measured by each instrument in turn. In later experiments two or more breathing valves were connected in a series, thus enabling measurement of the O 2 uptake simultaneously by more than one instrument. The O 2 uptake measured by the Metamax analysers rose linearly by the value given by the control methods. However, there were variations of 5% because the relationships differed between subjects. When the data from each subject were examined separately, the error of regression was 0.5 - 1 µmol s -1 kg -1 (2 - 3%), and the error of regression when relating the O 2 uptake to the exercise intensity was similar to that found when using the Douglas bag technique alone. In most cases the lung ventilation reported by the Metamaxes was a few percent less than that given by the control methods, while the fractional extraction of O 2 was higher for the Metamaxes. The respiratory exchange ratios (R-value) reported by the Metamaxes were in good agreement with those of the control methods in the range 0.9 - 1.0 only; for this parameter, the Metamaxes do not seem to be reliable for exercise testing. The O 2 uptake and the R-value were also calculated from the raw data reported by the Metamaxes. The calculated values differed somewhat from those reported by the instruments, and the calculated values were more in agreement with those obtained by the Douglas bag technique than those reported by the instrument. This study suggests that the O 2 uptake reported by the Metamaxes is precisely measured within subjects but that there are some systematic errors as well as variations between subjects.

Effect of intensive acupuncture on pain-related social and psychological variables for women with chronic neck and shoulder pain – an RCT with six month and three year follow up

Objectives This study examines whether intensive acupuncture treatment can improve several social and psychological variables for women with chronic pain in the neck and shoulders, and whether possible effects are long-lasting. The effects on pain have been reported elsewhere. Methods Twenty-four female office workers (47±9 years old, mean ± SD) who had had neck and shoulder pain for 12±9 years, were randomly assigned to a test group or a control group. Acupuncture was applied 10 times during three to four weeks either at presumed acupuncture points for pain (test group) or at sham points (control group). In addition, acupressure was given to patients between treatments, at either real or sham points. Questionnaires for social and psychological variables were completed before each treatment, just after the course, and six months and three years later. Results The pain-related activity impairment at work was significantly less in the test group than the controls by the end of treatment (P<0.04). Also there were significant differences between the groups for quality of sleep, anxiety, depression and satisfaction with life (P<0.05). At six months and three years follow ups the acupuncture group showed further improvements in most variables and was again significantly different from the control group. Conclusion Intensive acupuncture treatment may improve activity at work and several relevant social and psychological variables for women with chronic pain in the neck and shoulders. The effect may last for at least three years.

Effect of strenuous strength training on the Na-K pump concentration in skeletal muscle of well-trained men.

Abstract This study examined how strenuous strength training affected the Na-K pump concentration in the knee extensor muscle of well-trained men and whether leg muscle strength and endurance was related to the pump concentration. First, the pump concentration, taken as 3H-ouabain binding, was measured in top alpine skiers since strength training is important to them. Second, well-trained subjects carried out strenuous eccentric resistance training either 1, 2, or 3 times · week−1 for 3 months. The Na-K pump concentration, the maximal muscle strength in a full squat lift (one repetition maximum, 1 RM), and the muscle endurance, taken as the number of full squat lifts of a mass of 70% of the 1 RM load, were measured before and after the training period. The mean pump concentration of the alpine skiers was 425 (SEM 11) nmol · kg−1 wet muscle mass. The subjects in part two increased their maximal strength in a dose-dependent manner. The muscle endurance increased for all subjects but independently of the training programme. From a mean starting value of 356 (SEM 6) nmol · kg−1 the mean Na-K pump concentration increased by 54 (SEM 15) nmol · kg−1 (+15%, P < 0.001) when the results for all subjects were pooled. The effect was larger for those who had trained twice a week than for those who had trained only once a week (P=0.025), suggesting that the effect of strength training depended on the amount of training carried out. The muscle strength and endurance were not related to the pump concentration, suggesting that the pumping power of this enzyme did not limit the performance during heavy lifting. However, the individual improvements in the endurance test during the training period correlated with the individual changes in the pump concentration (rSpearman=0.5; P=0.01) which could mean that a common factor both increases the pump concentration and makes the muscles more adapted to repeated heavy lifting.

Energy cost of the Trondheim firefighter test for experienced firefighters.

Aim. The aim of this study was to measure aerobic demands of fire fighting activities including exercise in the heat. Methods. Twenty-two experienced firefighters performed the Trondheim test simulating fire fighting tasks including work in the heat. Maximal oxygen uptake (VO2 max), heart rate (HR) and ventilation were recorded continuously. Data were compared with results obtained during a treadmill test during which the participants were dressed as smoke divers. Results. The participants completed physical parts of the Trondheim test in ~12 min (range: 7.5–17.4). Time to complete the test was closely related to the participant’s VO2max. HR of ~170 beats/min and pulmonary ventilation of ~100 L/min were higher than at lactate threshold (LT) during laboratory tests. VO2 averaged over the test’s physical part was 35 ± 7 ml/min/kg, which was at the same or below the level corresponding to the participants’ LT. Physically fit participants completed the test faster than less fit participants. Slower and physically less fit participants consumed more air and used more oxygen than faster and physically more fit participants. Conclusion. The Trondheim test is physically demanding; it distinguishes physically fit and less fit participants.

Examination of the Moxus Modular Metabolic System by the Douglas-bag technique

The purpose of this study was to examine the performance of the Moxus Modular Metabolic System from AEI Technologies, Inc. using the Douglas-bag method as reference. To achieve this, eight moderately trained subjects cycled for 5 min at constant powers from 50 to 300 W in increments of 50 W. The O₂ uptake was measured simultaneously by both systems during the last minute of each stage. The O₂ uptake reported by the Moxus system was 83 ± 78 mL·min⁻¹ higher (mean ± SD; ≈3%, +62 µmol·s⁻¹, P < 0.001) than that reported by the Douglas-bag method; the bias varied by ≈2% between the subjects. The higher O₂ uptake of the Moxus system was a consequence of 1.4% ± 3.0% higher reported ventilation and 2% ± 3% higher reported O₂ extraction per volume of air breathed. The respiratory exchange ratio (R value) reported by the Moxus system rose proportionally to that of the Douglas-bag method and was 1% ± 2% higher for the range examined (0.75-1.10). Repeated tests of the maximal O₂ uptake showed a variability (coefficient of variation) of 2.5%. The study concluded that measurements by the Moxus system showed some bias and residual variation and, in addition, some systematic differences between the subjects in the O₂ uptake. The R value was reported quite accurately with moderate random error. Although there were some computer software and hardware instability problems that need to be solved, the Moxus system worked quite well and provided data more reliable than those of most commercial instruments.

New examination of the performance of the MetaMax I metabolic analyser with the Douglas-bag technique.

Abstract Purpose. To examine the performance of the MetaMax® I metabolic analyser of Cortex Biophysik, running a recent version of the software (MetaSoft v. 1.11.05), using the Douglas-bag method as reference. Experiments. First, 182 measurements of the maximal O2 uptake on school children were analysed both by a former version of the software (MetaMax Analysis) and by a recent version (MetaSoft). In further experiments, seven grown-up subjects of different fitness levels cycled for 5 min at constant powers between 50 and 350 W while the O2 uptake was measured simultaneously by the MetaMax I and the Douglas-bag method during the last minute of altogether 39 exercises. Results. The calculated maximal O2 uptake of the 182 school children was on average 3% lower when the data were reanalysed by MetaSoft than when analysed by the former version of the software. There was in addition a 2% variation. In further experiments on grown-up subjects the O2 uptake reported by the MetaMax I did not differ from that reported by the Douglas-bag system when data for all subjects were pooled, and the random error was 4%. However, the relationships differed slightly between the subjects (p = 0.005), and consequently the random error within each subject was 2–3%. The respiratory exchange ratio (R-value) reported by the MetaMax I differed systematically from that of the control method. However, a reliable R-value could be calculated from the instruments raw data. Conclusions. Our data suggest that the MetaMax I running MetaSoft reports unbiased values of the O2 uptake and with moderate random error.

Performance on a work-simulating firefighter test versus approved laboratory tests for firefighters and applicants.

Aim. Firefighters must meet minimum physical demands. The Norwegian Labour Inspection Authority (NLIA) has approved a standardised treadmill walking test and 3 simple strength tests for smoke divers. The results of the Trondheim test were compared with those of the NLIA tests taking into account possible effects of age, experience level and gender. Methods. Four groups of participants took part in the tests: 19 young experienced firefighters, 24 senior male firefighters and inexperienced applicants, 12 male and 8 female. Results. Oxygen uptake (VO2) at exhaustion rose linearly by the duration of the treadmill test. Time spent on the Trondheim test was closely related to performance time and peak VO2 on the treadmill test. Senior experienced firefighters did not perform better than equally fit young applicants. However, female applicants performed poorer on the Trondheim test than on the treadmill test. Performance on the Trondheim test was not closely related to muscle strength beyond a minimum. Conclusion. Firefighters completing the Trondheim test in under 19 min fit the requirements of the NLIA treadmill test. The Trondheim test can be used as an alternative to the NLIA tests for testing aerobic fitness but not for muscular strength. Women’s result of the Trondheim test were poorer than the results of the NLIA treadmill test, probably because of their lower body mass.

Association between perceived present working conditions and demands versus attitude to early retirement among construction workers.

BACKGROUND Early retirement is an increasing problem in the construction industry. There is limited information about causes leading employees to leave working life early. We have compared construction workers present situation with their perception of future demands at work to avoid early retirement. METHODS All 87 employees in a medium-sized Norwegian construction company participated in the study. All were men and answered questionnaires on health and pain, work ability, mechanical exposure, psychosocial conditions, and demands regarding future working conditions. RESULTS Most workers showed good work ability, irrespective of age. Many reported high levels of mechanical exposure at work. The level of musculoskeletal pain was higher in the middle-aged (30-50 year old) age groups and seniors aged over 50 years than among the youngest workers less than 30 years of age. All workers reported that good health was important for continued working. Most workers stated that future work must not be too physically demanding. Many workers reported relatively low job satisfaction; consequently an interesting job was rated as important for continuing work. Good social conditions were a high priority. CONCLUSIONS According to the examined construction workers, good health and reduced levels of mechanical exposure at work are essential to avoid early retirement.

Lactate elimination and glycogen resynthesis after intense bicycling

Objective. Muscles break down glycogen to lactate during intense exercise, and in the recovery period, glycogen reappears while lactate disappears. The purpose of this study was to examine to what extent lactate is resynthesized to glycogen within the formerly active muscles themselves in man. Material and methods. Fifteen healthy young men cycled for 2 min to exhaustion. Muscle biopsies were taken from the knee extensor muscle before the exercise, just after the ride, and again after 45 min of recovery. In addition, blood samples were taken from the femoral artery and vein, and the leg blood flow was measured using the ultrasound Doppler technique. The muscle biopsies were analysed for glycogen, lactate and other metabolites, and the blood samples were analysed for lactate and glucose. The exchanges of lactate and glucose of the leg were assessed by multiplying the measured arterio–venous (a–v) differences by the blood flow. Results. During the exercise the muscles broke down 20±4 mmol glycogen kg−1 wet muscle mass and produced 26±1 mmol lactate kg−1. In the recovery period after 24±1 mmol lactate kg−1 had disappeared, of which 48 % was released to the blood, 52 % disappeared within the muscle. An R‐value of 0.62 across the leg suggests that none of the lactate was oxidized. Altogether, 10±3 mmol glycogen kg−1 reappeared during recovery. Glucose uptake accounted for 2 mmol kg−1 and glycolytic intermediates (G‐6‐P and free glucose) accounted for 4 mmol kg−1; 4 mmol glycogen kg−1 (42 %) reappeared from unknown sources. Conclusions. The present data are compatible with the idea that around half of the lactate produced during intense bicycling is resynthesized to glycogen within the working muscles themselves in the recovery period after the bicycling.