Long-term strength training for community-dwelling people over 75: impact on muscle function, functional ability and life style

The objective was to determine the impact of a 1-year mixed strength-training programme on muscle function, functional ability, physical activity and life style. Twice-a-week hospital-based exercise classes and a once-a-week home session were conducted. Nineteen healthy community-dwelling training (T) men (76.6 +/- 3.1 years), 19 women (77.5 +/- 4.0 years) and 20 matched controls (C) participated in this study. Training was given with a two multi-gym machines for the lower limbs (Sitting calf and Leg press, TECHNOGYM, Italy) at 60% of the repetition maximum (1 RM) and at home it was with elastic bands. The following were the measurements made: muscle function-maximum isometric strength of the knee extensors (KE) and ankle plantar flexors (PF) measured with a Cybex Norm dynamometer, leg extensor power (LEP) with the Nottingham Power Rig; functional abilities-functional reach, chair rise, bed rise, 6-min walking test, stair climbing, get up and go, one-leg standing; physical activity-aerobic activities over 3 MET intensity (AA3), intensity classes; life-style-mean daily energy expenditure (MDEE). Significant gains in muscle function and functional abilities in both training females and males were observed, but females improved significantly more than males. Males (T + C) showed higher AA3 times than females (T + C) (P = 0.02), with females significantly more involved in light-intensity activities. We observed a 60% increase (t = 2.45) in AA3 time in T, but no increase in C. Trained males increased Class 2 physical activity time by 146% (t = 2.82) and trained females by 16% (t = 2.23). MDEE increased by 10% (t=2.62) in trained males. Our long-term mixed programme can improve muscle function and functional abilities in elderly females and functional abilities in males. It can positively affect the amount of habitual physical activity and the life-style of males and females over 75.

Effects of a partially supervised training program in subjects over 75 years of age

BACKGROUND AND AIMS

Partially supervised training programs may be preferable than class-based ones in older subjects because the adherence rate is more likely to be good and they cost less. The main purpose of this investigation was to provide some evidence of the effectiveness of a 4-month partially supervised training program. We compared it with a class-based program focusing on the knee extensor (KE) and ankle plantar flexor (APF) muscles.

METHODS

We selected for the study 14 subjects over 75 years of age (75+), age range 75 to 83 years with a mean age of 77.8, and 14 subjects over 65 years of age (65+), age range 65 to 72 years, mean age 66.3 years. They were moderately physically active subjects, free from neurological, cardiovascular, metabolic or inflammatory diseases. The two groups underwent two 4-month training sessions 3 days a week, including: warm-up, aerobics, strength training, cool-down exercises. 65+ subjects underwent a class-based program three times a week. 75+ subjects underwent a partially supervised program consisting of two supervised sessions and one session at home. Strength training was carried out bilaterally with the "Leg Press" and "Sitting Calf" variable-resistance machines (Technogym, Italy). The subjects performed one set of 10 repetitions with a 2-min rest in between. At home, 75+ subjects were instructed to carry out the strength exercises with graded elastic bands (Theraband). Subjects were tested immediately before and after the 4-month training. In addition to weight-lifting ability (1RM), we measured the isometric maximum strength values of KE and APF with a Cybex Norm dynamometer at various angles.

RESULTS

Significant baseline differences between 75+ and 65+ were found at all KE angles except 30 degrees and -20 degrees APF. A significantly increased maximum load (1RM) was observed over the 4-month period. The baseline and post-training torque-angle relationships for APF and KE in the two groups showed higher post-training gains in 75+ at all angles except at -20 degrees APF, although a statistically significant difference (p < 0.005) between the groups was only found at 30 degrees KE.

CONCLUSION

Our baseline data confirm the decay in torque capacity in subjects aged 75+ compared with 65+. The partially supervised training for 75+ subjects showed better responses in terms of relative strength gain than for 65+ subjects, and it appears effective in counteracting the age-related physiological and functional decay which appears to be particularly evident around that age.

Muscle function and functional ability improves more in community-dwelling older women with a mixed-strength training programme

BACKGROUND

Supervised training can reach a limited number of elderly people.

OBJECTIVE

To determine the impact of a 1-year mixed-strength training programme on muscle function (MF), functional ability (FA) and physical activity (PA).

SETTING

Twice-a-week hospital-based exercise classes and a once-a-week home session.

PARTICIPANTS

twenty-eight healthy community-dwelling men and women on the training programme and 20 controls aged over 75 years.

METHODS

Training with two multi-gym machines for the lower limbs at 60% of the repetition maximum (1RM). At-home subjects used elastic bands.

MEASUREMENTS

Maximum isometric strength of knee extensors (KE), ankle plantar flexors (PF), leg extensor power (LEP), functional reach (FR), chair rise 1 (CR1) and 10 times (CR10), bed rise (BR), six-minute walking test (6MWT), stair climbing (SC), get-up-and-go (GU&G), one-leg standing (1LS). PA was assessed with the Paqap questionnaire.

RESULTS

Women were significantly weaker than men at baseline: -47% for KE and -59% for PF. Training induced significant gains in MF and FA in the training females; males improved significantly only in FA. PA levels increased non-significantly (2%) in all of the training group.

CONCLUSIONS

Long-term mixed-strength programmes can improve MF and FA in elderly females, and FA in elderly males.

[De Quervain's tenosynovitis and work with hand tools: a case study]

Work-related musculoskeletal disorders of the upper limbs are a frequent complaint and their pathogenetic mechanism is often related to mechanical overload of the body region involved without traumatic events. The occupational origin of such disorders is much debated, since the clinical pictures are often not specific and may be found in subjects who do not perform hazardous work tasks. A better understanding of the relationship between clinical symptoms, diagnosis, and functional capacity would provide a deeper knowledge in decision making for return to work and rehabilitation strategies. In this paper we present a case study of a worker using scissors who developed De Quervain's syndrome in the dominant hand. A methodology for the biomechanical investigation of the work task and the possible occupational aetiology of the clinical picture are discussed according to the findings of the specific literature.

Impact of physical training and detraining on endothelium-dependent vasodilation in patients with recent acute myocardial infarction

BACKGROUND

There is evidence that aerobic exercise improves endothelial function in healthy subjects as well as in patients with chronic heart failure. However, it is unknown whether this effect occurs in patients with recent myocardial infarction (AMI).

METHODS

Fifty-two patients with a recent first uncomplicated AMI underwent endothelial function evaluation before and after 3 months of moderate aerobic exercise training. We measured brachial artery vasomotor reactivity using flow-mediated dilation (FMD), a cold pressor (CP) test, and sublingual nitroglycerin. Patients were randomized into 2 groups: 28 patients (G1) underwent training, while 24 patients (G2) served as controls. Brachial artery vasomotor reactivity was reassessed after 1 month of detraining (DT).

RESULTS

At baseline the FMD was 1.66% +/- 4.11% in G1 and 2.04% +/- 3.4% in G2 (P = NS) and vasoconstriction was evident after a CP test. The diameter reduction was -4.1% +/- 3.89% in G1 and -4.39% +/- 5.67% in G2 (P = NS). At follow-up the FMD had increased to 9.39% +/- 4.87% in G1 (P <.01) and to 4.4% +/- 3.9% in G2 (P <.01 vs G1). Vasoconstriction during a CP test was observed only in G2. Endothelium-independent vasodilation was unchanged in both groups. Effort tolerance increased by 32% in G1 patients (P <.01 versus G2) and was correlated with FMD change (R = 0.51, P <.01). After detraining the FMD was significantly reduced in G1 (P <.01) and a further vasoconstriction was evident after CP testing.

CONCLUSIONS

Exercise training improves endothelium-dependent vasodilation in post-AMI patients. This improvement is associated with a significant increase in exercise tolerance. These benefits disappeared after detraining.

Effect of aging on human muscle architecture

The effect of aging on human gastrocnemius medialis (GM) muscle architecture was evaluated by comparing morphometric measurements on 14 young (aged 27-42 yr) and on 16 older (aged 70-81 yr) physically active men, matched for height, body mass, and physical activity. GM muscle anatomic cross-sectional area (ACSA) and volume (Vol) were measured by computerized tomography, and GM fascicle length (Lf) and pennation angle (theta) were assessed by ultrasonography. GM physiological cross-sectional area (PCSA) was calculated as the ratio of Vol/Lf. In the elderly, ACSA and Vol were, respectively, 19.1% (P < 0.005) and 25.4% (P < 0.001) smaller than in the young adults. Also, Lf and were found to be smaller in the elderly group by 10.2% (P < 0.01) and 13.2% (P < 0.01), respectively. When the data for the young and elderly adults were pooled together, significantly correlated with ACSA (P < 0.05). Because of the reduced Vol and Lf in the elderly group, the resulting PCSA was found to be 15.2% (P < 0.05) smaller. In conclusion, this study demonstrates that aging significantly affects human skeletal muscle architecture. These structural alterations are expected to have implications for muscle function in old age.

Strength and power changes of the human plantar flexors and knee extensors in response to resistance training in old age

AIM

The aim of the present study was to assess and compare the improvements of muscle strength and power induced by a 16-week resistive programme in a population of 16 older men aged 65-81 years.

METHODS

Training was performed three times per week at an intensity of 80% of one repetition maximum (1RM) and consisted of both calf raise and leg press exercises. Before-, during- and after-training, maximum isometric and isokinetic torques, maximum power, 1RM, muscle cross-sectional area (CSA) and electromyographic activity (EMG) of the plantar flexors (PF) and knee extensors (KE) were examined.

RESULTS

For the KE and PF, respectively, training resulted in a 29.9 +/- 4.4% (mean +/- SE) and 21.6 +/- 5.4% increase in 1RM (P < 0.001-0.01), a 19.4 +/- 4.3 and 12.4 +/- 4.7% (P < 0.001-0.05) increase in maximum isometric torque, and a 24.1 +/- 6.3 and 33.1 +/- 10.9% (P < 0.05) increase in maximum muscle power, calculated from torque-angular velocity curves. The large increase in torque and power was partly accounted by a significant increase in the CSA of the PF (5.0 +/- 0.7%) and KE (7.4 +/- 0.7%), while no significant changes in integrated EMG activity of vastus lateralis and soleus muscles, and in extrapolated maximum shortening velocity were found. After training, a significant increase in torque/CSA (10.3 +/- 4%, P < 0.05) was found for the KE but not for the PF.

CONCLUSION

Hence, hypertrophy cannot alone justify the increase in torque, and other factors, such as an increase in individual fibre-specific tension (in the case of KE), a decrease in antagonist muscles' coactivation, an improved co-ordination and an increased neural drive of the other heads of quadriceps may have contributed to the increments in strength. The significant increase in muscle power seems particularly noteworthy with respect to daily activities involving the displacement of the body over time, namely, the generation of muscle power.

Plantar flexor activation capacity and H reflex in older adults: adaptations to strength training

The purpose of this study was to investigate whether the voluntary neural drive and the excitability of the reflex arc could be modulated by training, even in old age. To this aim, the effects of a 16-wk strengthening program on plantar flexor voluntary activation (VA) and on the maximum Hoffman reflex (H(max))-to-maximum M wave (M(max)) ratio were investigated in 14 elderly men (65-80 yr). After training, isometric maximum voluntary contraction (MVC) increased by 18% (P < 0.05) and weight-lifting ability by 24% (P < 0.001). Twitch contraction time decreased by 8% (P < 0.01), but no changes in half relaxation time and in peak twitch torque were observed. The VA, assessed by twitch interpolation, increased from 95 to 98% (P < 0.05). Pretraining VA, also evaluated from the expected MVC for total twitch occlusion, was 7% higher (P < 0.01) than MVC. This discrepancy persisted after training. The interpolated twitch torque-voluntary torque relationship was fitted by a nonlinear model and was found to deviate from linearity for torque levels >65% MVC. Compared with younger men (24-35 yr), the H(max)- to M(max) ratio and nerve conduction velocity (H index) of the older group were significantly lower (42%, P < 0.05; and 29%, P < 0.001, respectively) and were not modulated by training. In conclusion, older men seem to preserve a high VA of plantar flexors. However, the impaired functionality of the reflex pathway with aging and the lack of modulation with exercise suggest that the decrease in the H(max)- to M(max) ratio and H index may be related to degenerative phenomena.

The role of work simulation tests in a comprehensive cardiac rehabilitation program

BACKGROUND

One of the goals of a comprehensive cardiac rehabilitation (CR) program is the patient's return to his or her usual activities. The aims of this paper were to implement an occupational evaluation protocol in a CR and to assess patients' hemodynamic responses and ventricular arrhythmias during work simulation tests.

METHODS

After an 8-week outpatient CR, 132 patients performed work simulation, lifting (MH-L) and carrying (MH-C) tests. ECG, heart rate and blood pressure were constantly monitored.

RESULTS

The comparison of physiological responses during work simulation and a standard exercise testing provided the following results: 1) maximal heart rate, blood pressure and double product values during WS and MH tests were significantly lower (p < 0.001) than those measured during exercise testing; 2) higher (p < 0.001) double product values were achieved during MH-C as compared to MH-L and work simulation; 3) arrhythmias were more frequent during MH-L as compared to exercise test (p < 0.001). The increment of double product was reached much faster during work simulation and MH tests as compared to exercise testing: according to the multivariate analysis this was a predictor of a greater incidence of arrhythmias. The incidence of arrhythmias during work simulation tests and MH was significantly higher in patients with reduced tolerance to effort, valvular replacement, arrhythmias during holter monitoring, low ejection fraction and effort silent ischaemia.

CONCLUSIONS

Work simulation test provide a more personal functional assessment, complementary to the exercise testing. It appears particularly useful in patients with higher functional impairment who are at a higher risk of arrhythmias.

Effectiveness of a home-based strengthening program for elderly males in Italy. A preliminary study

BACKGROUND AND AIMS

The practice of regular physical exercise has been shown to be effective in slowing the age-related progressive functional deterioration. Most exercise trials have been conducted with supervised training programs. The purpose of this study was to investigate the effectiveness of a 4-month home-based strength training on strength, function and personal satisfaction.

METHODS

Ten elderly men (mean age 68.5 years) were enrolled for home-based training one month after completing a 4-month supervised program; 12 age-matched men served as the control group. Subjects were asked to perform 3 sessions a week consisting of six resistance exercises with elastic bands involving the major muscle groups of the upper and lower limbs. We had calculated the correlation between the elongation and resistance of the elastic bands. The subjects were instructed to keep a diary reporting the execution of the session. We measured dynamic concentric strength of the muscle groups involved in the resistance exercises and maximal isometric strength of the knee extensors and elbow flexors before and after the 4-month home training. The Satisfaction Profile (SAT-P) questionnaire was administered before and one month after the completion of the training program for assessing personal satisfaction.

RESULTS

The final to baseline comparison showed a non-significant decrease in mean isometric maximal strength values for knee extensors and elbow flexors in the control group, while the exercise group significantly (p=0.001) improved the average baseline values. Maximal dynamic concentric strength values decreased significantly in the control group, while significant improvements were observed in the exercising subjects. The SAT-P questionnaire did not show any difference in either group from baseline. The adherence-to-protocol rate based on self-report was 78%.

CONCLUSIONS

Home training with elastic bands appears to be an effective low-cost modality of maintaining strength and function in an elderly population.

The use of subjective rating of exertion in Ergonomics

In Ergonomics, the use of psychophysical methods for subjectively evaluating work tasks and determining acceptable loads has become more common. Daily activities at the work site are studied not only with physiological methods but also with perceptual estimation and production methods. The psychophysical methods are of special interest in field studies of short-term work tasks for which valid physiological measurements are difficult to obtain. The perceived exertion, difficulty and fatigue that a person experiences in a certain work situation is an important sign of a real or objective load. Measurement of the physical load with physiological parameters is not sufficient since it does not take into consideration the particular difficulty of the performance or the capacity of the individual. It is often difficult from technical and biomechanical analyses to understand the seriousness of a difficulty that a person experiences. Physiological determinations give important information, but they may be insufficient due to the technical problems in obtaining relevant but simple measurements for short-term activities or activities involving special movement patterns. Perceptual estimations using Borg's scales give important information because the severity of a task's difficulty depends on the individual doing the work. Observation is the most simple and used means to assess job demands. Other evaluations integrating observation are the followings: indirect estimation of energy expenditure based on prediction equations or direct measurement of oxygen consumption; measurements of forces, angles and biomechanical parameters; measurements of physiological and neurophysiological parameters during tasks. It is recommended that determinations of performances of occupational activities assess rating of perceived exertion and integrate these measurements of intensity levels with those of activity's type, duration and frequency. A better estimate of the degree of physical activity of individuals thus can be obtained.

Effects of a 16-week progressive high-intensity strength training (HIST) on indexes of bone turnover in men over 65 years: a randomized controlled study

The aim of the present study was to evaluate the effects of a 16-week progressive high-intensity strength training (HIST) program on peripheral markers of bone turnover (bone Gla protein, BGP; bone alkaline phosphatase, B-AP; N-terminal propeptide of type I procollagen, PINP; C-terminal cross-linked telopeptide of type I collagen, ICTP) in healthy, elderly men over 65 yr of age. Thirty healthy men (aged 65-81 yr), performing light to moderate daily physical activity, were randomly divided into two groups. Group 1 (no.=16) followed a supervised 16-week progressive HIST program, while subjects of group 2 (no.=14), used as controls, were requested to maintain their habitual level of physical activity for 16 weeks. HIST program consisted of 6 different sets of exercise (2 involving the major muscle groups of the lower limb and 4 involving those of the upper limb). Three sessions/ week, during which 10 repetitions of each exercise set were completed, were performed. Lower limb exercises shifted from 50 to 80% of the one maximal repetition (1 MR) during the first month of the protocol and were thereafter maintained at an intensity of 80% 1 MR throughout the training. Upper limb exercises shifted from 40 to 65% of 1 MR with a similar pattern. All sessions were preceded by 15 min of cycloergometer exercise at 50% of maximal oxygen uptake and by a warm-up of 15 repetitions at 20% of 1 MR of each exercise set. The HIST program did not significantly change BGP (mean SE, before: 15.6 +/- 1.2 microg/l vs after: 16.0 +/- 1.2 microg/l, NS) and PINP levels (before: 44.6 +/- 6.7 microg/l vs after: 43.1 +/- 6.0 microg/l, NS). On the contrary, serum B-AP significantly increased (before: 50.2 +/- 6.1 IU/l vs after: 62.3 +/- 7.0 lU/l, p<0.001) and serum ICTP slightly reduced (before: 4.0 +/- 0.3 microg/l vs after: 3.8 +/- 0.3 microg/l, p<0.05). When bone turnover was expressed as the ratio between bone formation to bone resorption (B-AP/ICTP ratio), a significant improvement in this ratio was found in all subjects of group 1 (before: 12.9 +/- 1.3 lU/microg vs after: 17.3 +/- 1.5 IU/microg, p<0.0001), while no significant changes were observed in Group 2. No significant changes of IGF-I levels were observed after the HIST program (before: 94.9 +/- 9.4 microg/l vs after: 89.9 +/- 9.7 microg/l). No significant changes of BGP, PINP, B-AP, ICTP, B-AP-ICTP ratio and IGF-I levels were observed in controls (group 2) during the 16 weeks of observation. Although the positive effects of a progressive HIST program on B-AP levels and B-AP-ICTP ratio seem promising, the support of bone mass measurement and the determination of other bone markers are requested to better identify exercise protocol (duration, intensity) for elderly people.

[Efficacy of a chair with magnets in the prevention of musculo-skeletal disorders caused by prolonged sitting]

The aim of the present paper was to evaluate the effectiveness of a sitting system based on the application of magnetic fields in the prevention of posture-related musculoskeletal disorders. We studied 5 healthy male volunteers during laboratory simulation tests including 60-minute sessions of "driving" and computer-work. Two subjects performed a 60-minute driving test on an isotonic dynamometer with a steering wheel, in which they had to steer for 2 min and drive normally for 3 min, alternatively. They repeated the test with and without the magnet-based sitting system. Three subjects performed a 60-minute computer-work test in a seated position with and without the magnet-based sitting system. EMG activity was registered in the trapezius muscles and at L1 and L5 lumbar level bilaterally with surface electrodes. The EMG trapezius activity continuously recorded was analysed with the APDF method, as proposed by Jonsson. Before and after the tests, the subjects performed a 60-sec isometric back extension at 60% MVC with a specific back dynamometer, while paraspinal EMG was recorded. The slope of decay of the median frequency of the EMG power spectrum was then calculated as an index of localised muscle fatigue. The results showed a decreased myoelectric activity both at shoulder and lumbar level by using the magnet-based sitting system for prolonged seated work tasks. Thus, the system appears to be an effective tool in preventing muscle contractures secondary to prolonged, constrained positions.

[Physical exercise in the prevention of musculoskeletal diseases in the elderly worker]

This paper reviews the impact of ageing on physical work capacity in the elderly worker and the benefits of exercise programmes designed for the prevention of musculo-skeletal complaints. Physical work capacity generally declines significantly after 50 years of age as a consequence of a reduction in aerobic capacity and muscle strength. The latter is accompanied by a decline in the fatigue threshold. This, in combination with a reduced recovery capacity after exercise, may lead to chronic overload of muscles and tendons in the elderly worker. Thus, it has been proposed that physical exercise programmes may prevent the onset of musculo-skeletal disorders. The effectiveness of different physical exercise programmes proposed in the literature for the prevention of musculo-skeletal disorders is reviewed here. The adoption of an active life-style and the rational use of ergonomic interventions, such as automatization of certain work processes, also appear to be crucial in minimizing the impact of ageing on work ability and capacity in the elderly worker.

[Aging and work: health aspects in cleaners]

Over the last few years, studies on the relationship between ageing and work have attracted growing interest due to the increased probability among workers of developing major health problems as a consequence of ageing workers. Negative outcomes for health are possible when an age-related imbalance appears between physical workload and physical work capacity. Cleaning could be considered as a paradigm for studying the relationship between ageing and physically demanding jobs. Cleaning workers show a high proportion of ageing women who are at the bottom level of the social-status class and are generally poorly educated with low income and social support level. This study, particularly aimed at highlighting the presence of musculo-skeletal disorders, was conducted by means of standardized questionnaires and protocols for collecting anamnestic and clinical data. The results show an increased prevalence of disorders of elbow, wrist/hand and cervical spine which could be caused by work organization and non-ergonomic tools. On the basis of the experience gained it was possible to propose solutions for the ageing working population concerning the workload, health surveillance methods and the ergonomic measures as regards organization, work place and tools.

[A project for the occupational reintegration of impaired subjects]

In this paper we have explained the criteria for an integrated socio-medical intervention (Local Health Care Institution, Cooperation, Scientific Institute of Care and Research) within the frame of a Communitary Initiative titled "Local network for return to work of persons with social disadvantage". The goal of the Initiative is to "create and experiment new facilities to support intervention strategies for return-to-work, and to start a virtuous circle matching the demands of both the disadvantaged persons and the local labour market". In the paper we describe the functional evaluations, performed in the Medical Center of Pavia by specialists in the field of Rehabilitation, Psychology and Ergonomy, and the following return-to-work phase, performed by operators of the Cooperation.

[Multifactorial ergonomic evaluation of the hospital nursing activity in assisting not self-sufficient patients]

8 Institutes of Health Care and Research of Northern-Central Italy participated in the study, which consisted of on-site investigations, interviews with the chief-nurse, and monitoring of physiological and subjective variables. We studied the most critical phases in the laboratory, by means of video-graphical systems for biomechanical and postural analysis. The outlined profile shows a demanding activity, yielding important risk factors relative to musculoskeletal lesions. The preventive attitude (education, training) must be implemented by ergonomic interventions, aimed to minimize the risk related to manual handling.

Work-related posttraumatic upper limb disorder. A case report

In this paper we describe a patient with mor-sensory loss in the right forearm and hand, which persisted more than 2 years after work-related crush trauma of the left hand. Radiographic and electromyographic investigations, somatosensory evoked potentials, CT scans of the encephalus as well as the Minnesota Multiphasic Personality Inventory and the Roarschach test have been performed. On the basis of these investigations, we think this represents a case of conversion disorder with somatic features. Included is a brief overview of other psychological illness with physical findings involving the upper limb.

[Ergonomic evaluation of the physical tasks in "precision fusion" operations]

In the present paper we performed an "on-site" ergonomic analysis of the work tasks in in-plant industrial workers. Specific work cycles have been identified and analysed. We measured spatial and temporal parameters of the different actions performed by the workers, and we then defined the related risk levels according to the internationally accepted guide-lines. The results obtained indicate the need of an ergonomic intervention with the aim of providing structural changes in the work station.

[An ergonomic study of postures of toll collectors]

The working activities of operators in the workstations along the italian motor ways involve repetitive movements of upper limbs and neck with asymmetric postures of the trunk. The tasks examined are characterized by factors potentially dangerous for developing musculo-skeletal disorders, such as repetitivity, and prolonged constrained postures. It is therefore crucial that dimensional and structural characteristics of the workplace are adequately designed, with regard to the anthropometric parameters and the type of activity performed. The results of our "on-site" investigation, using an observational method (OCRA), dedicated computerized modules for postural analysis (software "Vision 3000", Promatek, Ltd.), and recordings of myoelectrical activity (surface EMG) in the muscles of the shoulder girdle, have shown the need of a partial re-designing of the man-workstation system under investigation.

[Evaluation of the capacity of work using upper limbs after radical latero-cervical surgery]

Evaluation of arm work capacity after radical neck surgery. The aim of this paper is to describe an approach for the assessment of work capacity in patients who underwent radical neck surgery, including those treated with radiation therapy. Nine male patients, who underwent radical neck surgery 2 months before being referred to our Unit, participated in the study. In addition to manual muscle strength test, we performed the following functional evaluations: 0-100 Constant scale for shoulder function; maximal shoulder strength in adduction/abduction and intrarotation/extrarotation; instrumental. We measured maximal isokinetic strength (10 repetitions) with a computerized dynamometer (Lido WorkSET) set at 100 degrees/sec. During the rehabilitation phase, the patients' mechanical parameters, the perception of effort, pain or discomfort, and the range of movement were monitored while performing daily/occupational task individually chosen on the simulator (Lido WorkSET) under isotonic conditions. On this basis, patients were encouraged to return to levels of daily physical activities compatible with the individual tolerable work load. The second evaluation at 2 month confirmed that the integrated rehabilitation protocol successfully increased patients' capacities and "trust" in their physical capacity. According to the literature, the use of isokinetic and isotonic exercise programs appears to decrease shoulder rehabilitation time. In our experience an excellent compliance has been noted. One of the advantages of the method proposed is to provide quantitative reports of the functional capacity and therefore to facilitate return-to-work of patients who underwent radical neck surgery.

Work capacity of the upper limbs after mastectomy

Cancer patients are now more often long-term survivors and their needs for returning to social and productive activities have become a primary focus of intervention. The purpose of the present study was to propose an objective evaluation test for predicting endurance capacity in breast cancer patients after surgery, in order to optimize return to work or previous daily activities, and for monitoring changes during rehabilitation. Twenty female patients (mean age: 44 +/- 5), who underwent radical breast surgery 2 months before being referred to our Unit, participated in the study. In addition to the measures of the circumferences in the arm-forearm and manual muscle strength test, we performed the following functional evaluations: 0-100 Constant scale for shoulder function; instrumental evaluation of daily/occupational upper limb activities (Lido WorkSET). We monitored the mechanical parameters, the perception of effort, pain or discomfort, and the range of movement while performing a 3-minute steady daily/occupational task chosen by the subject. Patients were asked to perform the 3-minute test at three different intensities ("moderate", "somewhat hard", "hard") until the perception of fatigue, pain or discomfort was rated > 3 on the 10 point Borg's scale. The 'power-duration' product (Watt x min) defined by the three tests (see Fig. 1) represented the individual tolerable work load, since subjective indicators of pain/discomfort remained within tolerable limits during the exertion. On this basis, patients were encouraged to return to levels of daily physical activities compatible with the individual tolerable work load. The second evaluation, although no statistical analysis was performed, confirmed that the "guided" daily activity in a 2-month period increased patients' capacities and "trust" in their physical capacity.

Tolerability to prolonged lifting tasks. A validation of the recommended limits

Prolonged physical exertion is subjectively regulated by the perception of effort. This preliminary study was conducted to validate the use of subjective perceptions of effort in assessing objectively tolerable workloads for prolonged lifting tasks. Ten healthy male subjects tested their maximal lifting capacity (MLC) on a lift dynamometer (LidoLift, Loredan Biomed., West Sacramento, CA) and underwent incremental and 30-minute endurance lifting tests. Cardiorespiratory parameters were monitored with an oxygen uptake analyzer, mechanical parameters were calculated using a computerized dynamometer. Ratings of perceived exertion were given on Borg's 10-point scale. Physiological responses to repetitive lifting were matched with subjective perceptions. A single-variable statistical regression for power functions was performed to obtain the individual "iso-perception" curves as functions of the mechanical work exerted. We found that the "iso-perception" curve corresponding to a "moderate" perception of effort may represent the individual "tolerance threshold" for prolonged lifting tasks, since physiological responses at this level of intensity did not change significantly and the respiratory exchange ratio was less than one. The individually tolerable weight for lifting tasks lasting 30 min has been expressed as a percentage of the isoinertial MLC value and compared with the currently recommended limits for prolonged lifting tasks (Italian legislation D.L. 626/94). On the basis of our preliminary results a "tolerance threshold" of 20% MLC has been proposed for prolonged lifting tasks.

A field methodology for ergonomic analysis in occupational manual materials handling

A methodology is presented for the 'on-site' evaluation of work-related physical activities. In a first session, video recordings were made of six industrial plant workers during their routine occupational tasks. Heart rate (HR) and subjective perception of effort were monitored. The video recordings were then analysed with appropriate software to determine the musculo-skeletal load ('Vision 3000', Promatek, Montreal) and to evaluate energy expenditure ('Energy', University of Michigan). The indirect estimates of energy expenditure were validated in a second session by monitoring the six subjects' oxygen consumption (VO2) during the same activities with a portable telemetric oxygen uptake analyser (Cosmed 'K2', Rome). No statistically significant differences were found between direct measurements of VO2 and the computerised estimates of energy expenditure. Biomechanical parameters obtained in the two sessions did not differ. Therefore, we conclude that the 'Energy' programme and the 'Vision 3000' program provide a fast and reliable profile of job requirements.