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Background Dupuytren’s contracture was recently designated a prescribed occupational disease when it occurs in patients with previous hand–arm vibration (HAV) exposure. Aims The aims of this study were to describe the impact of self-reported HAV exposure on upper limb function and satisfaction following surgery for Dupuytren’s contracture. Methods Paired pre- and postoperative Quick version of Disabilities of the Arm, Shoulder and Hand (QuickDASH) and patient satisfaction questionnaires were prospectively collected from all patients undergoing surgery for Dupuytren’s contracture over a 6-year period. Patients self-reported HAV exposure duration. Results Results were available for 425 hands (65%) at mean 13 months postoperatively. There were 111 patients (26%) that reported HAV exposure. The prevalence of HAV exposure was significantly greater in male compared with female patients (32% versus 4%; P < 0.001). A statistically significant difference in preoperative (difference 7.47; 95% confidence interval 4.78–10.17; P < 0.001) and postoperative QuickDASH score (difference 6.78; 95% confidence interval 2.69–10.88; P < 0.001) was observed between the two groups, but difference in QuickDASH improvement was not significantly different (difference 1.76; 95% confidence interval −1.58 to 5.10; P > 0.05). No significant difference in satisfaction rate or return to work was observed between the two groups. Conclusions Previous HAV exposure influenced the pre and postoperative function in patients undergoing surgery for Dupuytren’s contracture, but had no effect on satisfaction or return to work. Further prospective research will be required to determine whether the introduction of a compensatory framework will have a more profound effect on the functional outcomes of surgery.

ObjectiveTo estimate the prevalence of hand-arm vibration (HAV) in Australian workplaces.MethodsThe Australian Workplace Exposure Survey (AWES)—Hearing was a cross-sectional telephone survey of Australian workers conducted in 2016–2017. Respondents were asked about the time spent using tools or performing tasks known to be associated with HAV during their most recent working day. We created a library of HAV magnitude levels for each tool/task and estimated each worker’s daily HAV exposure level using standard formulae. We categorized each worker as to whether they exceeded the daily occupational limits of 2.5 and 5.0 m/s2. Results were extrapolated to the Australian working population using a raked weighting method.ResultsIn our sample of 4991 workers, 5.4% of men and 0.7% of women exceeded the HAV action limit of 2.5 m/s2 on their most recent working day. We estimate that 3.8% of the Australian workforce exceeds the HAV limit of 2.5 m/s2 and 0.8% exceeds the 5 m/s2 limit. Men were more likely to exceed the HAV limits than women, as were those with trade qualifications, and those who worked in remote locations. Workers in the construction, farming, and automobile industries had the highest prevalence of HAV exposure. Tool groups that contributed to higher exposure levels included: compactors, rollers, and tampers; power hammers and jackhammers; and underground mining equipment.ConclusionsHAV is common in the Australian working population. Given the health risks associated with this exposure, reduction strategies and interventions should be developed, with engineering controls as the starting point for exposure reduction strategies.

Background Hearing loss is one of the most prevalent worker health conditions worldwide. Although the effect of noise exposure on hearing is well researched, other workplace exposures may account for significant hearing loss. The aim of this review was to determine whether occupational hand–arm vibration exposure through use of power or pneumatic tools, independent of noise exposure, is associated with permanent hearing loss. Do workers suffer from hand–arm vibration–induced hearing loss? Methods Peer-reviewed articles published in English between 1981 and 2020 were identified through five online databases with five search keywords. Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, including online database search methodology, study selection, article exclusion, and assessment of potential study design confounders and biases, were followed. Results Database searches retrieved 697 articles. Fifteen articles that reported 17 studies met the criteria for review. All but two studies revealed statistically significant associations between occupational exposure to hand–arm vibration and hearing loss. The majority of the study results revealed associations between hand–arm vibration and hearing loss, independent of potential age and noise confounders. Conclusion Few studies have examined the association between occupational exposure to hand–arm vibration and hearing loss. Dose response data were limited as only one study measured vibration intensity and duration. Although the majority of studies identified statistically significant associations, causal relationships could not be determined. Further research using standardized and uniform measurement protocols is needed to confirm whether the association between occupational exposure to hand–arm vibration and permanent hearing loss is causal and the mechanism(s).

BackgroundTesting of vibration perception threshold (VPT) at the fingertips as a quantitative measure of tactile sensitivity is a commonly used tool in diagnosing hand–arm vibration syndrome. There is limited research on dose–response relationships between hand–arm vibration (HAV) exposure and VPT on an individual level.AimsAssess possible dose–response relationships on an individual level between HAV exposure and VPT at the fingertips.MethodsWe assessed average daily vibration exposure (m/s2A8) and cumulative lifetime HAV exposure for 104 participants from different departments in a road maintenance company based on vibration measurements and questionnaires. VPT was measured based on the technical method described in ISO 13091-1:2005 using octave frequencies 8–500 Hz. We investigated associations using linear regression models with significance level p≤0.05.ResultsThe participants were either exposed to rock drills (n=33), impact wrenches (n=52) or none of these tools (n=19). Exposure to rock drills and impact wrenches was associated with elevated VPT for all seven test frequencies in the second and fifth fingers of both hands. A dose–response with the daily exposure measure m/s2(A8) was found based on 1.2 m/s2(A8) for impact wrenches, and 5.4 m/s2(A8) for rock drills. A stronger association was found with the cumulative exposure for rock drills compared with impact wrenches, and for the second finger compared with the fifth finger.ConclusionsHAV exposure was associated with elevated VPT, also at exposure levels below the common exposure action value of 2.5 m/s2(A8). Lowering the HAV exposure can contribute to prevent increasing VPTs in these workers.

Background Non-automated tool handles transmit a large magnitude of vibration to operators' hands, causing discomfort and pain. Therefore, the need for a better handle design is a matter of prime concern to overcome musculoskeletal disorders such as hand-arm vibration syndrome. Objective This study aimed to examine the influence of handle shapes in reducing the transmission of hand-arm vibration. Methods Seven different handles were designed and fabricated using 3D printing technology at the SSN College of Engineering, with consideration for the anatomical shape of the hand. The frequency-weighted Root Mean Square (RMS) values of the vibration levels transmitted were recorded at the wrist of twelve subjects, unaffected by musculoskeletal disorders. Subjective ratings of vibration and comfort perception were measured using the Borg Scale of Perceived Exertion. Results The total vibration value (ahv) of each of the six novel prototype handles (B-G) was compared to that of the reference handle denoted handle-A. The vibration reductions for handles B to G respectively were 0.542 m/s2 (14.59%), 0.481 m/s2 (12.95%), 0.351 m/s2 (9.45%), 0.270 m/s2 (7.27%), 0.407 m/s2 (10.96%) and 0.192 m/s2 (5.17%). Conclusions A significant level of vibration reduction was achieved by the prototype handles. Qualitative feedback from the study subjects suggests that they were not aware of the levels of vibration being transmitted to the hand with each handle.

Objectives To assess the hazard of tool vibrations, we need valid exposure measurements. The use of hand-attached accelerometers (vibration sensors) to measure hand-arm vibrations (HAVs) has become a popular approach. However, according to International Standard ISO 5349-2, the preferred attachment of accelerometers is at the tool handle. We compared measures of HAV between hand- and tool-attached accelerometers in rock drilling. Methods We measured HAV in five rock drillers using jackleg drills in normal working operations with simultaneous measures of both hand-attached and tool-attached accelerometers. Five to seven measurement cycles of 15 s were executed on each worker, resulting in a total of 29 measurement cycles. To identify possible differences in working technique, we recorded videos of tool handle handgrips during drilling. Results There was a significant difference (9.5 m s−2; P ≤ 0.05) in vibration magnitudes measured by the tool-attached accelerometers compared with the hand-attached accelerometers. The hand-attached accelerometer showed a lower vibration magnitude for all workers (range of difference: 2.3–14.6). The variation between the two accelerometer attachments was larger between workers than within workers (ICC = 0.68). Conclusions For measurements of HAV from jackleg drills, the use of hand-attached accelerometers may cause a lower recorded vibration level compared with tool-attached accelerometers. This difference is likely to vary depending on how workers grip the tool handle, and a misclassification of exposure will occur if workers grip the tool handle in a way that makes the accelerometer lose contact with the vibrating surface. Individual differences in how workers grip the tool handles should be considered when assessing HAV.

Objective: To investigate whether low molecular organic biomarkers could be identified in blood samples from vibration exposed workers using a metabolomics. Methods: The study population consisted of 38 metalworkers. All participants underwent a standardized medical examination. Blood samples were collected before and after work shift and analyzed with gas chromatography time-of-flight mass spectrometry. Multivariate modeling (orthogonal partial least-squares analysis with discriminant analysis [OPLS-DA]) were used to verify differences in metabolic profiles. Results: Twenty-two study participants reported vascular symptoms judged as vibration-related. The metabolic profile from participants with vibration-induced white fingers (VWF) was distinctly separated from participants without VWF, both before and after vibration exposure. Conclusion: Metabolites that differed between the groups were identified both before and after exposure. Some of these metabolites might be indicators of health effects from exposure to vibrations. This is the first time that a metabolomic approach has been used in workers exposed to vibrations.

During recent years the number of tennis athletes has increased significantly. When playing tennis, the human body is exposed to many situations which can lead to human injuries, such as the so-called tennis elbow (lateral epicondylitis). In this work a biomechanical analysis of tennis athletes, particularly during the service, was performed, considering three different types of over-grip and the presence of one anti-vibrator device. One part of the study evaluates the exposure to hand-arm vibration of the athlete, based on the European Directive 2002/44/EC concerning the minimum health and safety requirements, regarding the exposure of workers to risks from physical agents. The second part of the study considers an infrared thermography analysis in order to identify signs of risk of injury, particularly tennis elbow, one of the most common injuries in this sport. The results show that the presence of the anti-vibrator influences the vibration values greatly in the case of athletes with more experience and also for athletes with less performance. The presence of the Cork and/or Tourna on the racket grip does not have any significant effect on the hand-arm vibration (HAV), similarly in the case of athletes with the best performance and athletes with less technique. The results indicated that the infrared thermography technique may be used to identify the risk of injuries in tennis players.

Hand-arm vibration (HAV) from hand-held vibrating machines increases the risk of injury in the form of vasoconstriction in the fingers, commonly named as vibration induced white fingers (VWF). Cold temperature may increase that risk. This experimental study examined and compared the effects of the skin temperature of the hands during and after exposure to HAV in thermoneutral and cold conditions. Fourteen subjects were exposed to three conditions: 25°C with HAV, 5°C with HAV or 5°C without HAV. Their skin temperatures were continuously recorded for the thumbs, index fingers, palms, and back of hands. After 20 min of acclimatization, the subjects held, for five min, two handles where the right handle could vibrate at 5 m/s2 and the left was stationary. Finally, they released their grip and stood still for 10 more min. HAV had no additional cooling effect in cold during gripping of the handles. After the subjects released the handles there was only a HAV-induced cooling effect in the left palm with on average 0.5°C colder skin temperature. A single exposure to HAV will not cause an injury such as VWF, but as the present study show: short-term exposure to HAV causes some changes in skin temperature.

Objectives of this study are to analyze the HAV exposures of chipping hammer operators from field measurements and to investigate the potential of various types of gloves in reducing the exposures. HAV exposures of twelve male operators were measured at four different operating conditions: bare hand, wearing normal workman gloves, wearing heavy workman gloves and wearing vibration reducing gloves. From the measurements, 8 h exposure values were determined and assessed against standards. The total vibration values were determined and effectiveness in vibration attenuation by gloves was compared. It was found that all most all operators, HAV exposure levels exceeded the exposure action value (EAV) and about 83% of the operators exceeded the exposure limit values (ELV). A reduction in the total vibration magnitude was observed with protective gloves: 8.3% with normal workman gloves, 14.6% with heavy workman gloves and 40% with vibration-reducing gloves. To confirm the effectiveness of the vibration reducing gloves, further field investigations are required with simultaneous measurements by considering parameters affecting HAV (i.e., hand forces and postures).

Teaching professionals regularly use the chalk board eraser or duster throughout their life which leads to several unnoticed musculoskeletal disorders. The purpose of this study was to provide an alternate design for the existing Indian model chalk board eraser, because current eraser design causes noticeable amount of biomechanical load on the wrist, hand and shoulder region when its frequency of usage was high and repetitive. Initially, pilot study was conducted through an online modified Nordic questionnaire among 60 college professors to identify the risky regions of the body due to the use of existing chalk board eraser. This was followed by an experimental trial using surface Electromyography Sensors (sEMG) in which the muscle behaviour was evaluated during the chalkboard erasing process employing three newly designed dusters and a traditional duster. The results revealed that Model A designed with a large palm rest to align the palm and the forearm had better usability and the musculoskeletal distress was reduced when compared with the traditional duster. Whereas Model C designed with slip guards to improve the gripping forces was found to have better performance rating after Model A. Model B provided with separate handle was found to be the worst performer when compared with the conventional duster. Results suggested that providing an improved palm rest and slip guards such as grooves reduces the musculoskeletal distress.

Work with vibrating tools is common in many industries. Exposure to hand-arm vibrations is associated with a risk of hand injury in the form of: Vascular disorders, nerve malfunction, and effects on the musculoskeletal system. The aim of this study was to investigate the prevalence of hand-arm vibration symptoms among employees at a mechanical company, as well as to follow-up with patients presenting symptoms and evaluate the effects of certain proposed measures. We found that 21% of the employees were judged to have vibration-related problems even though the exposure to vibrations was judged to be relatively low. There seems to be an over-representation of Carpal tunnel syndrome among participants; this may suggest that ergonomic conditions at the investigated company, such as grinding with flexed wrists, are unfavorable. Relevance to industry Regular screening for early signs of vibration-related damage, even if workers are subject to only moderate vibration exposure, is an important part of preventing the aggravation of health problems.

An experimental study has been performed on the effect of exposure to noise (N), vibration (V), and combined noise and vibration (NV), on the distortion product otoacoustic emission (DPOAE) level. The aim of the study is investigating the possible synergistic effect of noise and vibration, increasing the risk of damage to the hearing function due to noise only. Twelve normal-hearing volunteers were randomly exposed to hand arm vibration (HAV) only, noise only, and HAV and noise simultaneously. The exposure consisted of five consecutive sessions interspersed with quiet periods. DPOAEs were recorded during the quiet intervals following each exposure session, and during recovery, and compared to their baseline level, and among different test treatments. An ad hoc acquisition system developed in Labview was used to record high frequency-resolution DPOAE spectra in a suitably short time. Time-frequency filtering, based on the wavelet transform, was used to separate the DPOAE components coming from different generation mechanisms. The three test treatments, N, V, and NV, yielded significantly different results. The condition affecting most significantly all DPOAE component levels was the exposure to vibration only, causing a statistically significant increase of the signal level during all the exposure periods, with a decreasing trend during recovery. Also the exposure to noise only, N, caused a DPOAE level increase, statistically significant for the long latency (LL) DPOAE component. Only when exposure to noise was in combination with vibration, the zero-latency (ZL) component was clearly suppressed during the exposure. The results suggest a synergistic adverse effect of noise and vibration on the cochlear function. Relevance to industry The simultaneous exposure to noise and hand arm vibration is a very common industrial scenario. The risk that exposure to mild noise levels could interfere with the exposure to vibration, enhancing the adverse effect on the hearing function, should be considered to optimize prevention strategies at the workplace.

Generally, and particularly at sports, the human body is constantly exposed to physical requests and to tests in many different situations. Although the practice of sports is considered a healthy act, there are limits and, when these limits are reached, the benefits of sport can turn into problems. Thus, the biodynamic response method is increasingly being used to study the human injuries induced by external vibrations. Moreover, the European Directive 2002/44/EC on the minimum health and safety requirements, regarding worker exposure to risks from physical agents (e.g. vibration), limit the exposure to vibrations. The aim of this study is to analyze the exposure level of cross motorcycle and of cycling drivers to hand-arm vibration (HAV) and to whole-body vibration (WBV). For this research, vibration levels of a common 200 cc cross motorcycle were experimentally measured and the maximum driving time that could be safely used in a stone road was established. Moreover, bicycle vibration measurements were performed using two different bicycles: a road cycling bike; a bike for track cycling. The road bike was evaluated at three road scenarios: asphalt; paved; and stone road pavement. The track bike was evaluated in track cycling and rollers. In the case of cycling the results indicate that impacts and transient vibrations lead to a higher musculoskeletal request particularly in what concerns shoulders, arms, wrists, knees and spine.

This study aimed to examine the effects of exertion force on endurance time, muscular activity and hand/arm tremor during holding. Fifteen healthy young males were recruited as participants. The independent variable was exertion force (20%, 40%, 60% and 80% maximum holding capacity). The dependent variables were endurance time, muscular activity and hand/arm tremor. The results showed that endurance time decreased with exertion force while muscular activity and hand/arm tremor increased with exertion force. Hand/arm tremor increased with holding time. Endurance time of 40%, 60% and 80% maximum holding capacity was approximately 22.7%, 12.0% and 5.6% of that of 20% maximum holding capacity, respectively. The rms (root mean square) acceleration of hand/arm tremor of the final phase of holding was 2.27-, 1.33-, 1.20- and 1.73-fold of that of the initial phase of holding for 20%, 40%, 60% and 80% maximum holding capacity, respectively.

PURPOSE: To provide an updated epidemiological validation for a supplementary method for assessing the risk of vascular disorders from hand-transmitted vibration. METHODS: The occurrence of vibration-induced white finger (VWF) in the vibration-exposed workers of the Italian cohort of the EU VIBRISKS study was related to measures of daily vibration exposure expressed in terms of r.m.s. acceleration magnitude normalised to an 8-h day, frequency weighted according to either the frequency weighting Wh defined in international standard ISO 5349-1:2001 [Ah(8) in ms- 2] or the hand-arm vascular frequency weighting Wp proposed in the ISO technical report (TR) 18570:2017 [Ap(8) in ms- 2]. To estimate a threshold value for vascular hand-arm vibration risk, the Wp-weighted vibration exposure value Ep,d (in ms- 1.5) was calculated according to the ISO/TR document. The difference in the predictions of VWF between the exposure measures calculated with the frequency weightings Wh or Wp was investigated by means of logistic modelling. RESULTS: Measures of daily vibration exposure constructed with the frequency weighting Wp [Ap(8) and Ep,d], which gives more importance to intermediate- and high-frequency vibration, were better predictors of the occurrence of VWF in the vibration-exposed workers than the metric derived from the conventional ISO frequency weighting Wh [Ah(8)]. There was some epidemiological evidence for a threshold value of Ep,d for the onset of VWF in the vibration-exposed workers. CONCLUSIONS: Measures of daily vibration exposure evaluated with the vascular weighting Wp performed better for the predictions of VWF than those obtained with the frequency weighting Wh recommended in ISO 5349-1.

Background: Occupational exposure to hand-transmitted vibration (HTV) is known to cause neurological symptoms such as numbness, reduced manual dexterity, grip strength and sensory perception. The purpose of this longitudinal study was to compare thermotactile perception thresholds for cold (TPTC) and warmth (TPTW) among vibration exposed manual workers and unexposed white collar workers during a follow-up period of 16 years to elucidate if long-term vibration exposure is related to a change in TPT over time. Methods: The study group consisted of male workers at a production workshop at which some of them were exposed to HTV. They were investigated in 1992 and followed-up in 2008. All participants were physically examined and performed TPT bilaterally at the middle and distal phalanges of the second finger. Two different vibration exposure dosages were calculated for each individual, i.e. the individual cumulative lifetime dose (mh/s2) or a lifetime 8-h equivalent daily exposure (m/s(2)). Results: A significant mean threshold difference was found for all subjects of about 4-5 degrees C and 1-2 degrees C in TPTW and TPTC, respectively, between follow-up and baseline. No significant mean difference in TPTC between vibration exposed and non-exposed workers at each occasion could be stated to exist. For TPTW a small but significant difference was found for the right index finger only. Age was strongly related to thermotactile perception threshold. The 8-h equivalent exposure level (A (8)) dropped from about 1.3 m/s2 in 1992 to about 0.7 m/s(2) in 2008. Conclusions: A lifetime 8-h equivalent daily exposure to hand-transmitted vibration less than 1.3 m/s(2) does not have a significant effect on thermotactile perception. Age, however, has a significant impact on the change of temperature perception thresholds why this covariate has to be considered when using TPT as a tool for health screening.

Olive harvesting with hand-held beaters is a repetitive work, tiring and time consuming (more than 4–5 h/day). Operators work with vibrating tools in not natural body postures: they are therefore exposed to various risks, especially at the upper limbs. Unfortunately, also if in the agriculture sector the number of the declared upper limb disorders increased in the last years, hand-arm vibration and incongruent upper limb postures are not yet well perceived. In this work, the hand-arm vibration exposure and the OCRA index were calculated for five operators which used three different electric olive beaters. In all the observed tests both the hand-arm vibration and the OCRA scores produced results over the admitted limits. A(8) ranged between 8.6 ms -2 and 25.4 ms -2 , far from the 5 ms -2 daily exposure limit values admitted by the European law (European Directive 2002/44). The OCRA checklist values ranged from a minimum value of 13.32 (red light level and light risk) for the left limb and a maximum of 34.41 (violet, high level and high risk) for the right limb. Relevance to industry This paper describes the analysis of the combined risks to hand-arm vibration and to upper limb disorders in a typical agricultural harvesting task with a manual handled tool powered by electric engine. Tests were carried out during the olive harvesting with five operators using three different hand-held machines. Both vibration and OCRA parameters were acquired. Results showed that in all the observed tests both the hand-arm vibration and the OCRA scores were over the admitted limits. Beaters transmitted vibration to both the operators’ hand-arm system, but operators did not declare to perceive vibration at the right upper limb (because it was less affected by the vibration stimulus than the left one). To acquire reliable values for the upper limb biomechanical risk detection it should be necessary to use measured vibration data in field, avoiding personal judgments. When it is not possible to measure the vibration level, the employer should use the machine instruction, where the manufacturer should have written the vibration total value to which the hand-arm system is subjected, if it exceeds 2,5 m/s 2 (European Directive 2006/42). When this information is not available in the machine instruction, the employer may refers to other sources (European Directive 2002/44), as databases provided by government or institutional bodies, including vibration values obtained by research specialists and vibration consultants.

New regression model for predicting hand‐arm vibration (HAV) of Malaysian Army (MA) three‐tonne truck steering wheels: Shamsul Akmar Ab Aziz, et al. Department of Mechanical and Material Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia (UKM), Malaysia OBJECTIVE: The objective of this study was to present a new method for determination of hand‐arm vibration (HAV) in Malaysian Army (MA) three‐tonne truck steering wheels based on changes in vehicle speed using regression model and the statistical analysis method known as Integrated Kurtosis‐Based Algorithm for Z‐Notch Filter Technique Vibro (I‐kaz Vibro). METHODOLOGY: The test was conducted for two different road conditions, tarmac and dirt roads. HAV exposure was measured using a Brüel & Kjær Type 3649 vibration analyzer, which is capable of recording HAV exposures from steering wheels. The data was analyzed using Ikaz Vibro to determine the HAV values in relation to varying speeds of a truck and to determine the degree of data scattering for HAV data signals. RESULTS: Based on the results obtained, HAV experienced by drivers can be determined using the daily vibration exposure A(8), I‐kaz Vibro coefficient (Ƶ (v) (∞)), and the I‐kaz Vibro display. The I‐kaz Vibro displays also showed greater scatterings, indicating that the values of Ƶ (v) (∞) and A(8) were increasing. Prediction of HAV exposure was done using the developed regression model and graphical representations of Ƶ (v) (∞). The results of the regression model showed that Ƶ (∞) increased when the vehicle speed and HAV exposure increased. DISCUSSION: For model validation, predicted and measured noise exposures were compared, and high coefficient of correlation (R (2)) values were obtained, indicating that good agreement was obtained between them. By using the developed regression model, we can easily predict HAV exposure from steering wheels for HAV exposure monitoring.

The hand coordinate systems for measuring vibration exposures and biodynamic responses have been standardized, but they are not actually used in many studies. This contradicts the purpose of the standardization. The objectives of this study were to identify the major sources of this problem, and to help define or identify better coordinate systems for the standardization. This study systematically reviewed the principles and definition methods, and evaluated typical hand coordinate systems. This study confirms that, as accelerometers remain the major technology for vibration measurement, it is reasonable to standardize two types of coordinate systems: a tool-based basicentric (BC) system and an anatomically based biodynamic (BD) system. However, these coordinate systems are not well defined in the current standard. Definition of the standard BC system is confusing, and it can be interpreted differently; as a result, it has been inconsistently applied in various standards and studies. The standard hand BD system is defined using the orientation of the third metacarpal bone. It is neither convenient nor defined based on important biological or biodynamic features. This explains why it is rarely used in practice. To resolve these inconsistencies and deficiencies, we proposed a revised method for defining the realistic handle BC system and an alternative method for defining the hand BD system. A fingertip-based BD system for measuring the principal grip force is also proposed based on an important feature of the grip force confirmed in this study.

European Directive 2002/44/EC defines employers' responsibilities in the risk management of hand-arm vibration (HAV). However, the directive is still not completely implemented in all risk industries. The aim of our study was to determine whether it is possible to improve the recognition and management of the risks of HAV at workplaces with a one-year information campaign. A questionnaire on opinions and measures for controlling HAV exposure at workplaces was sent to all occupational safety representatives and occupational safety managers in the construction and metal industry in Finland (n=1887) and once again to those who responded to the first questionnaire (n=961) one year after the campaign. The campaign increased recognition of HAV in risk assessment from 57.0% to 68.3% (p=.001), increased measures to decrease exposure to HAV from 54.6% to 64.2% (p=.006) and increased the number of programmes to control the risks due to HAV (p

Background: Hand–arm vibration syndrome is an occupational disease caused by exposure to hand–arm transmitted vibration. The Health and Safety Executive has set limits for vibration exposure, including an exposure action value (EAV), where steps should be taken to reduce exposure, and an exposure limit value (ELV), beyond which vibrating equipment must not be used for the rest of the working day. Aims: To measure hand–arm transmitted vibration among orthopaedic surgeons, who routinely use hand-operated saws. Methods: We undertook a cadaveric study measuring vibration associated with a tibial cut using battery-operated saws. Three surgeons undertook three tibial cuts each on cadaveric tibiae. Measurements were taken using a frequency-weighted root mean square acceleration, with the vibration total value calculated as the root of the sums squared in each of the three axes. Results: A mean (SD) vibration magnitude of 1 (0.2) m/s2 in the X-axis, 10.3 (1.9) m/s2 in the Y-axis and 4.2 (1.3) m/s2 in the Z-axis was observed. The weighted root mean squared magnitude of vibration was 11.3 (1.7) m/s2. These results suggest an EAV of 23 min and ELV of 1 h 33 min using this equipment. Conclusions: Our results demonstrate that use of a battery-operated sagittal saw can transmit levels of hand–arm vibration approaching the EAV or ELV through prolonged use. Further study is necessary to quantify this risk and establish whether surveillance is necessary for orthopaedic surgeons.

A biomechanical model is presented, and combined with measurements of tip press force, to estimate total user hand force associated with two pneumatic nail gun trigger systems. The contact actuation trigger (CAT) can fire a nail when the user holds the trigger depressed first and then “bumps” the nail gun tip against the workpiece. With a full sequential actuation trigger (SAT) the user must press the tip against the workpiece prior to activating the trigger. The SAT is demonstrably safer in reducing traumatic injury risk, but increases the duration (and magnitude) of tip force exertion. Time integrated (cumulative) hand force was calculated for a single user from measurements of the tip contact force with the workpiece and transfer time between nails as inputs to a static model of the nail gun and workpiece in two nailing task orientations. The model shows the hand force dependence upon the orientation of the workpiece in addition to the trigger system. Based on standard time allowances from work measurement systems (i.e. Methods-Time Measurement - 1) it is proposed that efficient application of hand force with the SAT in maintaining tip contact can reduce force exertion attributable to the sequential actuation trigger to 2–8% (horizontal nailing) and 9–20% (vertical nailing) of the total hand/arm force. The present model is useful for considering differences in cumulative hand/arm force exposure between the SAT and CAT systems and may explain the appeal of the CAT trigger in reducing the user’s perception of muscular effort.

The Hand Arm Risk assessment Method (HARM) is a simplified risk assessment method for determining musculoskeletal symptoms to the arm, neck and/or shoulder posed by hand-arm tasks of the upper body. The purpose of this study was to evaluate the predictive validity of HARM using data collected from a three year prospective cohort Study on Musculoskeletal disorders, Absenteeism and Health (SMASH). Structured observations of video recordings using HARM were made of 88 participants performing hand-arm tasks. These video recordings were made at baseline of the SMASH study, whereas self-reported musculoskeletal symptoms were assessed both at baseline and during a three year follow-up. The receiver operating characteristic (ROC) curves showed an area under the curve (AUC) of 0.75 (CI: 0.65-0.86) for symptoms at baseline and 0.70 (CI: 0.58-0.83) for symptoms during follow-up. For a HARM score of 50, the sensitivity and specificity were 64% and 79% at baseline and 53% and 82% during follow up. Participants with a HARM score of 50 or more (considered a high risk) had a significantly higher risk of upper limb symptoms than those with a HARM score of less than 50 at baseline (OR=5.31; 95%CI: 2.10-13.39) and 3 year follow-up (OR=5.11; (95%CI: 1.61-16.27). This study has shown that HARM can be used to assess work tasks of the hands and arms and discriminate between tasks that pose a high or low risk of neck or upper limb symptoms. Relevance to industry: The association of HARM results and self-reported neck and upper limb symptoms was studied. The association found both cross sectionally and at follow up shows that the method can be used in industry to distinguish hazardous hand arm tasks from non-hazardous ones. Thus, HARM can support OSH practitioners and industrial engineers in designing healthy workplaces. © 2013 Elsevier B.V.

Prolonged exposure to hand-transmitted vibration from grass-cutting machines has been associated with increasing occurrences of symptoms and signs of occupational diseases related to hand-arm vibration syndrome (HAVS).A cross-sectional study was carried out using an adopted HAVS questionnaire on hand-arm vibration exposure and symptoms distributed to 168 male workers from the grass and turf maintenance industry who use hand-held grass-cutting machines as part of their work. The prevalence ratio and symptom correlation to HAVS between high and low-moderate exposure risk groups were evaluated.There were positive HAVS symptoms relationships between the low-moderate exposure group and the high exposure group among hand-held grass-cutting workers. The prevalence ratio was considered high because there were indicators that fingers turned white and felt numb, 3.63, 95% CI [1.41, 9.39] and 4.24, 95% CI [2.18, 8.27], respectively. Less than 14.3% of workers stated that they were aware of the occupational hand-arm vibration, and it seemed to be related to the finger blanching and numbness.The results suggest that HAVS is under-diagnosed in Malaysia, especially in the agricultural sectors. More information related to safety and health awareness programmes for HAVS exposure is required among hand-held grass-cutting workers.

Evaluation of Protective Gloves and Work- ing Techniques for Reducing Hand-arm Vibration Exposure in the Workplace: Matija MILOSEVIC, et al. Electrical and Computer Engineering Department, Ryerson University, Canada—Objectives: Operation of handheld power tools results in exposure to hand-arm vibrations, which over time lead to numerous health complications. The objective of this study was to evaluate protective equipment and working techniques for the reduction of vibration exposure. Methods: Vibration transmissions were recorded during different work techniques: with one- and two-handed grip, while wearing protective gloves (standard, air and anti-vibra- tion gloves) and while holding a foam-covered tool handle. The effect was examined by analyzing the reduction of transmitted vibrations at the wrist. The vibration transmission was recorded with a portable device using a triaxial accelerometer. Results: The results suggest large and significant reductions of vibra- tion with appropriate safety equipment. Reductions of 85.6% were achieved when anti-vibration gloves were used. Conclusions: Our results indicated that trans- mitted vibrations were affected by several factors and could be measured and significantly reduced. (J Occup Health 2012; 54: 250-253)

Hand-transmitted vibration and the associated potential injuries are dependent on hand-arm posture, hand forces and other factors. This study presents biomechanical models consisting different substructures of the hand-arm system and the trunk of the body in different postures subject to zh-axis vibration. The trunk was considered in order to account for observed and reported considerable vibration at the shoulder and of the head. The models parameters were derived through error minimization using three different target biodynamic functions namely: driving-point mechanical impedance alone; localized vibration transmissibility responses alone; and combined simultaneously measured impedance and transmissibility responses. The results showed that the models’ parameters and responses are strongly dependent on the type of the target function. The models derived using impedance or transmissibility responses target function yield good comparisons with measured impedance or transmissibility responses, respectively, but none adequately characterize both the impedance and transmissibility responses. The models based on combined impedance and transmissibility target functions yield reasonably good comparisons with both measured biodynamic responses and characteristic frequencies. The results suggest that the transmissibility responses characterize the dynamics of the local tissues/muscles of the human hand-arm at different locations, while impedance characterizes the entire hand-arm system with emphasis around the driving-point. The results showed a strong coupling between the human hand-arm system and the whole-body. Relevance to industry Occupational exposure to hand-transmitted vibration has caused health problems in some operators of hand-held power tools. This has resulted in loss of manpower and costs in terms of compensations paid to affected workers. The existing International guidelines (ISO 5349-1, 2001) could not adequately predict some components of the hand-arm vibration syndrome due to lack of knowledge about hand-arm injury mechanism and probably due to neglect of the effect of posture adopted by workers in the assessment method. The biomechanical models for different postures presented in this study could be used to estimate distributed biodynamic responses (vibration power, dynamic forces, vibration intensity and deformation of joints) of the human hand-arm system exposed to vibration. Potential injury assessment based on these distributed biodynamic responses may yield better prediction of different components of the hand-arm injury and enhance understanding of injury mechanism.

The portable petrol driven grass trimmer is identified as a type of machine whose operator can be subjected to large magnitude of hand-arm vibration. These vibrations can cause complex vascular, neurological and musculoskeletal disorder, collectively named as hand-arm vibration syndrome. The vibration total level on the handle of grass trimmer of 11.30 m/s2 was measured, and it has reached the exposure limit value of 5.0 m/s2 for daily vibration exposure A(8). New suspended handles were designed to reduce the vibration level. Three different prototype handles with rubber mounts were designed. Handles were made of different materials, and the distance of rubber mounts were varied. From the study, it was observed that not all the handles with rubber mounts were effective in reducing hand-arm vibration. The reduction of vibration depended on the handle material and distance installed between rubber mount and vibration transmissibility of handle-isolation system. Subjective ratings of perception of vibration were measured, and the results indicated that operators were not fully aware of the level of vibration. A prototype handle that is made of heavier material results in the lowest hand-arm vibration of 2.69 m/s2. The new handle has significantly reduced the vibration total value by 76% compare with the existing commercial handle. Relevance to industry Large numbers of workers are employed to perform grass trimming job in many developing countries. This paper presents the effect of handle types (commercial and prototype) on the commonly used grass trimmer.

This study examined and compared the effect on temporary threshold shift in hearing (TTS) in healthy subjects of noise and hand-arm vibration (HAV) combined and separately using controlled and authentic exposure conditions. This study also investigated the effect on TTS in hearing in relation to gender after such exposures.Twenty-two healthy subjects (11 men/women, mean age 22 years, range 18-31 years) were exposed both separately and in combination with HAV (6.7 m/s(2)), using vibrating handles and to noise (99dB(A)) using headphones, for 20 min. The HAV and noise were reproduced from recordings from angular grinder in operation. Hearing thresholds at 1, 4, and 8 kHz were measured before and up to 30 min after exposure.Combined exposure to noise and HAV created significantly greater TTS in hearing than HAV exposure at 4 and 8 kHz alone. After exposure to HAV, there was no significant change in hearing threshold. At 1 kHz, there was a significant difference between noise and HAV exposure in TTS in hearing. There was no significant difference between combined exposure and noise exposure for any test frequency. There was no significant difference in TTS in hearing in relation to gender for 1, 4, and 8 kHz for HAV, noise, or a combined exposure.The results indicate that there is no difference in the TTS in hearing after combined exposure compared to noise exposure alone. HAV exposure did not change the hearing threshold. The TTS in hearing did not differ significantly in relation to gender after HAV, noise, or combined exposure.

Hand–arm vibration measurements are necessary for vibration exposure risk assessment and for the determination of vibration emission values in hand-guided machines. It has been reported that there is a high degree of uncertainty associated with this kind of measurement. The main goal of the present work is to investigate which factors cause uncertainty in hand–arm vibration evaluation and how much they contribute to the total uncertainty of the measurements. Some experiments were carried out in order to evaluate separately the factors relating to instrumentation and the methods of fixing accelerometers. The experiments were performed with handles belonging to real machines while being handheld by an operator. The results of this investigation show that the fixing method and the accelerometer behaviour are the two main sources of uncertainty. The total uncertainty of the measurements in this work, considering both instrumentation and fixing method, reaches up to 8% of the values measured. It is concluded that the adaptors for fixing the accelerometer with metallic stripe hose clips cause less uncertainty than handheld adaptors and should therefore be used as the first option. Relevance to industry A good accuracy in hand–arm measurements is the key for a correct assessment of the risk of developing HAVS (Hand–Arm Vibration Syndrome). Knowledge of the uncertainty factors will help the technicians who carry out the measurements to improve their quality.

Vibrating machines are used in a variety of occupations. Exposure to hand-arm vibration can cause vascular, neurological, and muscular symptoms in the hands and arms. This qualitative study provides a deeper understanding of the consequences of vibration injuries in women. In depth interviews were conducted with eight women with vibration injuries. The women were metal and wood product assemblers and dental personnel. The transcribed interviews were analyzed in accordance with the grounded theory method. The core category in the findings was "another life". This was constructed by the categories "consequences for everyday activities", "work performance", "household duties", "leisure", and "self perception" and shows that the injury had affected most parts of the women's lives and decreased their quality of life. The importance of well-functioning hands in all activities was highlighted. Reduced hand function due to numbness, muscle weakness, and pain caused restricted abilities to perform activities at work, at home, and during leisure time. The women described impact on their self-perception, as the injury had affected them in their roles as a worker, mother, and woman. The findings indicate that a vibration injury is a multidimensional problem that can affect every aspect of an individual's life. Health care providers should be aware of these complex consequences.

This study focuses on the acute effects of vibration and how vibrations influence the measures of the thermal perception thresholds during different vibration magnitudes, frequencies, and durations.The fingers of ten healthy subjects, five males and five females, were exposed to vibration under 16 conditions with a combination of different frequency, intensity and exposure time. The vibration frequency was 31.5 and 125 Hz and exposure lasted between 2 and 16 min. The energy-equivalent frequency weighted acceleration, according to ISO 5349-1, for the experimental time of 16 min was 2.5 or 5.0 m/s(2) (r.m.s.), corresponding to a 8-h equivalent acceleration, A(8) of 0.46 and 0.92 m/s(2), respectively. A measure of the thermal perception of cold and warmth was conducted before the different exposures to vibration. Immediately after the vibration exposure the acute effect was measured continuously on the exposed index finger for the first 75 s, followed by 30 s of measures at every minute for a maximum of 10 min. If the subject's thermal thresholds had not recovered, the measures continued for a maximum of 30 min with measurements taken every 5 min.For all experimental conditions and 30 s after exposure, the mean changes of the thresholds compared with the pre-test were found to be 0.05 and -0.67 degrees C for the warmth and cold thresholds, respectively. The effect of the vibration exposure was only significant on the cold threshold and only for the first minute after exposure when the threshold was decreased. The warmth threshold was not significantly affected at all. The frequency and the exposure time of the vibration stimuli had no significant influence on the perception thresholds for the sensation of cold or warmth. Increased equivalent frequency weighted acceleration resulted in a significant decrease of the subjects' cold threshold, not the warmth. The thresholds were unaffected when changes in the vibration magnitude were expressed as the frequency weighted acceleration or the unweighted acceleration.When testing for the thermotactile thresholds, exposure to vibration on the day of a test might influence the results. Until further knowledge is obtained the previous praxis of 2 h avoidance of vibration exposure before assessment is recommended.

There are several occupational illnesses related with vibration transmission from power hand tools to hand–arm system. International Standards have been developed to evaluate the risk of injury after exposure to this kind of vibrations; nevertheless, the current standards recognise that some aspects need to be investigated, such as the influence of vibration transmission direction, arm posture or hand grip force. To investigate these aspects an instrumented hand tool has been constructed by the author to measure the hand grip force and the energy transmission to the operator. The vibration applied is generated and controlled by an electro-dynamic shaker. The results of the experiment allow the authors to describe the dissipative model of hand–arm system, and therefore propose new frequency filters to weigh the accelerations obtained in tools depending on vibration transmission direction to hand–arm system. Relevant to industry The methodology proposed in this study provides a better evaluation of health risks associated with exposure to hand-transmitted vibration from power tools. The results obtained can also be used in handle design for new tools, which is more effective than personal protective equipment solutions, in order to minimise potential harm to operator's health.

Objectives The aim of the present study was to investigate the possible increase in hand tremor in relation to hand-arm vibration (HAV) exposure in a cohort of exposed and unexposed workers. Methods Participants were 178 male workers with or without exposure to HAV. The study is cross-sectional regarding the outcome of tremor and has a longitudinal design with respect to exposure. The dose of HAV exposure was collected via questionnaires and measurements at several follow-ups. The CATSYS Tremor Pen® was used for measuring postural tremor. Multiple linear regression methods were used to analyze associations between different tremor variables and HAV exposure, along with predictor variables with biological relevance. Results There were no statistically significant associations between the different tremor variables and cumulative HAV or current exposure. Age was a statistically significant predictor of variation in tremor outcomes for three of the four tremor variables, whereas nicotine use was a statistically significant predictor of either left or right hand or both hands for all four tremor variables. Conclusions In the present study, there was no evidence of an exposure–response association between HAV exposure and measured postural tremor. Increase in age and nicotine use appeared to be the strongest predictors of tremor.

This study examined onset time for reported vascular and neurological symptoms in relation to the vibration load in a group of workers exposed to vibration.Information on the self-stated year for the first occurrence of symptoms was collected by means of questionnaires. During interviews data were obtained on self-stated estimations of daily exposure time, type of tool, and number of months or years with different exposures. The estimations of the vibration magnitudes of exposure were based on conducted measurements. From these data, the individual vibration exposure at the time of onset of symptoms was calculated.The incidence was 25.6 and 32.9 per 1000 exposure years for vascular and neurological symptoms, respectively, in the group of workers. The first onset of symptoms appeared after an average of 12 years of exposure. For the workers, the symptoms of vascular or neurological disorders started after about the same number of exposure years. The calculated accumulated acceleration correlated best with the onset time of symptoms.It was concluded that, since the workers' exposure to vibration was below the action level established in the European vibration directive, the results suggest that the action level is not a safe level for avoiding vascular and neurological symptoms.

There are fewer women than men working in occupations with high exposure to hand–arm vibration. Still there are tens of thousands of women employed in these occupations. The aim of this study was to investigate the gender differences in the subjective experience of hand–arm vibration. Absolute vibrotactile threshold measurements at four frequencies (8, 31.5, 63 and 125 Hz) in 20 participants (10 males, 10 females) were obtained as well as perceived intensity and discomfort ratings of hand–arm vibration made at four intensity levels (0.16, 0.5, 1.6 and 5 m/s 2 ) for each frequency. No gender differences were found for threshold measurements. However, ratings of both perceived intensity and discomfort were higher for females. Females were significantly more subjectively sensitive than males to stronger physical intensity levels at the higher frequencies. Further, predicted rating values based on ISO frequency weighting underestimated female responses significantly more than male responses to perceived intensity. The results seen here indicate that there should be greater considerations to gender differences in studies of hand–arm vibration. Relevance to industry Results from this study demonstrate differential effects in subjective responses to hand–arm vibration in males and females. This may have implications for ISO frequency weighting currently used in industrial hygiene evaluations.

The influence of hand–arm posture on the biodynamic responses under zh-axis vibration is investigated in terms of driving point mechanical impedance and absorbed power under various combinations of hand grip and push forces, handle sizes and excitation levels. Laboratory measurements of the biodynamic responses were performed on seven healthy male subjects exposed to two levels of broadband random vibration in the 8–1000 Hz frequency range using three instrumented cylindrical handles of different diameter (30, 40 and 50 mm), and different grip (10, 30 and 50 N) and push (25, 50 and 75 N) forces. The experiments involved grasping the handle with two different postures, consisting in flexed forearm with elbow angle of 90° and extended forearm with elbow angle of 180°, with wrist being in the neutral position for both postures. The results revealed remarkable effects of the hand–arm posture on both the mechanical impedance and the absorbed power characteristics. The low-frequency apparent mass magnitude of the hand–arm with the extended forearm posture was observed to be approximately three times than that with the flexed forearm posture. Furthermore, the effects of handle size, and push and grip forces on the biodynamic responses of the human hand–arm exposed to vibration were observed to be more significant for the extended forearm posture. This posture revealed considerably higher coupling with the vibrating handle and a damper-like behavior of the hand–arm system in the very low-frequency range. This posture also resulted in considerably higher power absorption than the flexed forearm posture for the majority of the combinations of hand forces considered. Depending on the handle size, excitation level, and hand forces, the total power absorbed by the hand–arm with an extended hand–arm could be up to 96% higher than that with the flexed elbow. From the results, it is evident that the hand–arm posture strongly affects the biodynamic response, when exposed to zh-axis vibration. Relevance to industry Operators assume considerable variations in the hand–arm posture while operating hand-held power tools. Such variations coupled with variations in the hand forces imparted on the tool handle could cause considerably different biodynamic responses of the hand–arm system. The current International Standard describes the range of idealized biodynamic response in terms of the driving-point mechanical impedance under a fixed posture involving 90° elbow angle (ISO-10068, 1998). The standard on the assessment of anti-vibration gloves also requires the same posture (ISO-10819, 1996). This study presents the effect of hand–arm posture on the biodynamic responses in terms of both driving-point mechanical impedance and power absorption by the hand–arm system. The influences of hand forces and handle sizes on both measures are also presented. The results of the study clearly suggest high significance of the hand–arm posture in view of the biodynamic responses. The results of the study attained on the driving-point mechanical impedance are expected to provide the vital knowledge and data for enhancing the current standard and its applications. The results attained on the influence of posture on the absorbed power characteristics of the hand–arm system are further expected to enhance our knowledge on the assessment of vibration exposure.

A new frequency weighting method to assess hand-arm vibration exposure is proposed in this paper. The influence of frequency components was first estimated using the method of multivariate analysis, then a simple form of the weighting curve was introduced. Compared with the frequency weighting in the current ISO 5349-1 (2001), the proposed weighting can better explain the relationship between rates of symptoms and vibration exposure among vibrating tool users. Although this new weighting is derived from limited data, it suggests that the current weighting in ISO 5349-1 should be changed to give more weight to the high frequency range and less weight to the low frequency range.

The biodynamic responses of the hand-arm system under x(h)-axis vibration are investigated in terms of the driving point mechanical impedance (DPMI) and absorbed power in a laboratory study. For this purpose, seven healthy male subjects are exposed to two levels of random vibration in the 8-1,000 Hz frequency range, using three instrumented cylindrical handles of different diameters (30, 40 and 50 mm), and different combinations of grip (10, 30 and 50 N) and push (0, 25 and 50 N) forces. The experiments involve grasping the handle while adopting two different postures, involving elbow flexion of 90 degrees and 180 degrees, with wrist in the neutral position for both postures. The analyses of the results revealed peak DPMI magnitude and absorbed power responses near 25 Hz and 150 Hz, for majority of the test conditions considered. The frequency corresponding to the peak response increased with increasing hand forces. Unlike the absorbed power, the DPMI response was mostly observed to be insensitive to variations in the excitation magnitude. The handle diameter revealed obvious effects on the DPMI magnitude, specifically at frequencies above 250 Hz, which was not evident in the absorbed power due to relatively low velocity at higher frequencies. The influence of hand forces was also evident on the DPMI magnitude response particularly at frequencies. above 100 Hz, while the effect of hand-arm posture on the DPMI magnitude was nearly negligible. The magnitude of power absorbed within the hand and arm was observed to be strongly dependent upon the excitation level over the entire frequency range, while the influence of hand-arm posture on the total absorbed power was observed to be important. The effect of variations in the hand forces on the absorbed power was relatively small for the bent elbow posture, while an increase in either the grip or the push force coupled with the extended arm posture resulted in considerably higher energy absorption. The results suggested that the handle size, hand-arm posture and hand forces, produce coupled effect on the biodynamic response of the hand-arm system.

Measurements of changes in finger skin blood flow with laser Doppler perfusion imaging (LDPI) in response to cold provocation test (10 degrees C, 10 min) were performed in 12 men suffering from vibration induced white finger (VWF) and 13 exposed controls. The mean perfusion values in both groups reduced markedly as a result of immersion of the hand in cold water. In the controls, however, the mean value increased gradually until the end of the cold provocation, while that in the VWF subjects remained at the lowest level. After removal of the hand from the cold water, the skin blood perfusion in the controls recovered rapidly and nearly reached the baseline value. In the VWF subjects, it had a slight increase immediately following the cold immersion but no tendency to rise as the time span increased. Analysis of covariance controlling for possible confounders revealed that the VWF subjects had significantly lower perfusion values compared to the controls in the last several minutes of the cold provocation and the following recovery. These findings suggest that the LDPI technique enables visualizing and quantifying the peripheral vascular effects of cold water immersion on the finger skin blood perfusion and thus has the potential of providing more detailed and acurate information that may help detect the peripheral circulatory impairment in the fingers of vibration-exposed workers.

The frequency weighting for assessing hand-transmitted vibration exposure is critical to obtaining a true dose-response relationship. Any valid weighting must have a solid theoretical foundation. The objectives of this study are to examine the biodynamic foundation for assessing the vibration exposure and to develop a set of biodynamic methods to formulate the frequency weightings for different anatomical locations of the fingers-hand-arm system. The vibration transmissibility measured on the fingers, hand, wrist, elbow, shoulder, and head was used to define the transmitted acceleration-based (TAB) frequency weighting. The apparent masses measured at the fingers and the palm of the hand were used to construct the biodynamic force-based (BFB) weightings. These weightings were compared with the ISO weighting specified in ISO 5349-1 (2001). The results of this study suggest that the frequency weightings for the vibration-induced problems at different anatomical locations of the hand-arm system can be basically divided into three groups: (a) the weighting for the fingers and hand, (b) the weighting for the wrist, elbow, and shoulder, and (c) the weighting for the head. The ISO weighting is highly correlated with the weighting for the second group but not with the first and third groups. The TAB and BFB finger weightings are quite different at frequencies lower than 100 Hz, but they show similar trends at higher frequencies. Both TAB and BFB finger weightings at frequencies higher than 20 Hz are greater than the ISO weighting.

Manufacturers of ergonomic split keyboards promise maximum effectiveness and comfort as well as a reduction of physical complaints. In order to determine the positive effects claimed, a study was carried out during which 10 male subjects (Ss) participated in standardized working tests. They entered text into a PC, alternatingly using a conventional keyboard and an ergonomic keyboard. Electromyographic activity (EA) of 8 muscle groups was simultaneously recorded during altogether 6 working phases with a duration of 10 min, each. Measurements of the maximum activity, EAmax, via maximum voluntary contractions of the 8 muscles – which were necessary for calculating standardized electromyographic activity (sEA) used to represent muscle strain as a percentage – were always taken at the end of the experiment. Muscle strain varied from muscle to muscle but the level of the sEA-values for the different muscles was reproducible and stable. Also, activation of most muscles acting on the shoulder, upper arm, forearm, and the hand showed differences which, though small in amount, could be statistically secured and associated with the keyboard type. The ergonomic design of the tested keyboard led to objectively verifiable and plausible reductions of muscle strain.

Medical surveillance was used in the workplace to determine and monitor the level of hand-arm vibration syndrome (HAVS) and carpal tunnel syndrome (CTS) present in workers exposed to upper extremity vibration. Ergonomic intervention in the form of new tools with lower vibration levels and the use of International Standards Organizaiton (ISO) 10819 antivibration gloves were associated with a decrease in the pathologic findings and symptoms in these workers. Workers without such intervention were more likely to show progression of symptoms and findings. These findings suggest that ergonomic intervention can be effective in controlling the workplace hazard of tool vibration.

BACKGROUND Health surveillance (HS) is required for employees if noise or hand-arm vibration (HAV) exposures are likely to be above exposure action levels. The extent to which employers comply with Health and Safety Executive (HSE) regulations is unclear. AIMS To establish the uptake and quality of HS for noise and HAV in high-risk industries. METHODS A cross-sectional telephone-based questionnaire study involving employers in high-risk industries for noise or HAV. RESULTS A total of 246 and 386 interviews were completed for noise and HAV, respectively. The uptake of HS in the cohorts was 17 and 10%, respectively. Selection of those companies thought to have 'higher risk' increased the uptake to 25 and 18%, respectively. The proportion of companies carrying out HS was strongly related to the size of the company, with smaller companies less likely to provide this for their employees. A large proportion of companies that reported having HS in place had formal procedures for managing exposed workers (90 and 83% for noise and HAV, respectively), received feedback on individual workers (81 and 80%) and some reported that they used this information to inform their risk management process (58 and 63%). The frequency of HS for HAV was in line with that suggested in HSE guidance in 70% of cases, however, for noise, it was often utilized more frequently. CONCLUSIONS While many of the companies appear to be following HSE guidance, there is a significant number that are not. Further initiatives that engage with smaller companies may help increase HS provision.

Summary A frequently encountered exposure profile for hand-arm vibration in contemporary occupational setting comprises workers with a long history of intermittent exposure but without detectable signs of hand-arm vibration syndrome (HAVS). Yet, most of the published studies deal with developed HAVS cases, rarely discussing the biological processes that may be involved in degradation of manual dexterity and grip strength when it can be most beneficial - during the asymptomatic stage. In the present paper, a group of 31 male asymptomatic vibration-exposed workers (according to the Stockholm Workshop Scale) were compared against 30 male controls. They were tested using dynamometry and dexterimetry (modelling coarse and fine manual performance respectively) and cold provocation was done to detect possible differences in manual performance drop on these tests. The results showed reduced manual dexterity but no significant degradation in hand grip strength in the exposed subjects. This suggests that intermittent exposure profile and small cumulative vibration dose could only lead to a measurable deficit in manual dexterity but not hand grip strength even at non-negligible A(8) levels and long term exposures.

The objective of this study is to evaluate the influences of activation mode, torque and horizontal operating distance on hand–arm response while operating in-line pneumatic screwdrivers. Hand–arm response was investigated in terms of finger force exertion, flexor digitorum electromyography, and hand-transmitted vibration. Two activation modes (push-to-start, and trigger-to-start), two torque levels (low, and high) and three horizontal operating distance (far, middle, and near) were evaluated. Thirteen healthy male subjects drove screws into an iron plate with pre-tapped screw holes using in-line pneumatic screwdrivers in randomly ordered experimental conditions. The results indicate that the use of push-to-start mode, not only required a greater holding force involving forearm muscular exertion and middle, ring and small finger forces, but also incurred a greater hand-transmitted vibration than the use of trigger-to-start mode. Higher torque caused a greater hand-transmitted vibration and required a firmer grip than lower torque. A middle distance level (18–30 cm away from the table edge) is recommended as it is found to have the least hand-transmitted vibration and requires less finger force exertion. Relevance to industry The findings on the evaluation of the influence of activation mode, torque, and horizontal operating distance on hand–arm response can provide useful information for the design of assembly tasks using pneumatic screwdrivers as well as the design of powered hand tools.

A Cohort Study on Raynaud''s Phenomenon in Workers Exposed to Low Level Hand-Arm Vibration: Kotaro TOMIDA, et al. Department of Hygiene, School of Medicine, Wakayama Medical University-To clarify the incidence of Raynaud''s phenomenon among workers exposed to low level hand-arm vibration for a long time, a sample cohort of workers mainly operating a bush cleaner (the vibration level was 2-4 m/s2rms) were followed up for a period of 20 yr. The sample cohort consisted of 331 male workers mainly working at maintaining public roads or afforesting and gardening on a farm. The examination was based on questionnaires used in special medical examinations for vibration syndrome from 1977 to 1996. Raynaud''s phenomenon was observed in 11 subjects. The accumulative occurrence rate increased linearly in the case of more than 11 operating years. The mean number of operating years at the occurrence of Raynaud''s phenomenon was 11.7 ± 7.1 yr. The mean total operating time at the occurrence of Raynaud''s phenomenon was 3, 756 h on the geometric average. Stockholm Workshop scale classified 1 subject as Stage 1 (mild), 4 subjects Stage 2 (moderate) and 6 subjects Stage 3 (severe). By the person-year method, the incidence of Raynaud''s phenomenon was 4.48 per 1000 person-year. These findings show that the number of operating years for a bush cleaner should be considered to prevent Raynaud''s phenomenon, even though the hand-arm vibration level is low.

The objective of this study is to evaluate the effects of wearing a glove and wrist support on hand–arm response while operating an in-line pneumatic screwdriver. Hand–arm response was investigated in terms of triggering finger force, flexor digitorum EMG and hand-transmitted vibration. Four glove levels (barehanded, cotton, nylon and open-finger), and two wrist support levels (wearing, and not wearing) were evaluated. Thirteen healthy male subjects drove screws into a horizontally mounted iron plate with pre-tapped screw holes using an in-line pneumatic screwdriver in the randomly ordered experimental conditions. The results indicate that wearing a nylon glove and not using a wrist support is the best combination among the eight evaluated experimental conditions. Wearing a nylon glove reduced 18.2% of the triggering force as compared with the barehanded condition. In addition, wearing a nylon glove had comparatively low forearm muscular exertion, and reduced 16% and 15% of hand-transmitted vibration in the z-axis and the sum of 3-axes as compared with the barehanded condition. The use of a wrist support required a greater triggering force and a 9.9% greater hand-transmitted vibration in the y-axis than when not using a wrist support. Relevance to industry The results of this study can be applied to the design of assembly tasks in the electronic industry to reduce the risk of incurring upper extremity cumulative trauma disorders.

Background The objectives of the study were to examine whether occupational use of vibrating hand-held tools was associated with an impaired vibrotactile perception, whether any exposure-response ...