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瀬尾明彦 作業関連性筋骨格系障害に関わる計測と評価の手法
Seo, A.:Measuring and Evaluating Methods for Work-related Musculoskeletal Disorders
労働科学,81（1）,6〜15,（2005）
　
作業関連性筋骨格系障害に関連する作業要因の計測と負担評価のための主要な手法の現状と課題について概観した。まず取り扱い重量と操作力については、荷物重量の基本的な方法と、ひずみゲージなどによる力測定の方法と実際について述べた。次に筋電図計測について、そのアンプと信号処理の基本、身体構造と手法がもつ電気的な限界、運動単位活動電位による軽負荷作業の評価について述べた。作業姿勢計測については、モーションキャプチャシステムによる方法と各種センサーを利用する方法について述べた。最後に負荷の総合的評価法について、バイオメカニカル解析の各種モデルやパラメータの特徴およびその他の手法について述べた。(図5)（自抄）
キーワード：作業関連性筋骨格系障害，操作力，筋電図，作業姿勢，バイオメカニカルモデル

Akihiko SEO (Department of Intelligent Systems, Graduate School of Engineering, Tokyo Metropolitan Institute of Technology)
Measuring and Evaluating Methods for Work-related Musculoskeletal Disorders
THE JOURNAL OF SCIENCE OF LABOUR,81（1）,6〜15,（2005）
　
Objective methods for measureing and evaluating work-related musculoskeletal disorders are reviewed.　They included measuring weight and force, electromyographic analyses, monitoing postures and motions and biomechanical analyses.　The weight of objects handled is a simple index of the work load on the musculoskeletal system. It is, however, difficult to estimate the total workload when workers are in charge of various kinds of work dealing with various materials. For the measurement of handling force, strain gauges and load cells are often used to detect multi-axial forces and their directions. 　Electromyograms (EMG) can present the physical responses to external loads or forces. The optimum EMG processing can be selected from among signal processing software methods. In analyzing EMG data, attention shonld be paid to the locations of electrodes and the motion of the subject workers for proper estimation. Methods for measuring motor-unit action potentials are also developing to evaluate light workload tasks based on the Cinderella hypothesis. 　Working postures and motions are monitored by motion-capturing systems or by using various types of sensors. The motion-capturing systems use images from video cameras and estimate the real coordinates of target positions by the direct linear transformation method. For ambulatory measurement, the inclinometer by using acceleration sensors and other position sensors are desirable. 　Biomechanical analyses are one of the methods for estimating the total musculoskeletal workload. The outline of the estimation and evaluation of the low back compression force, muscle force estimation by optimizations and by EMG-assisted models as well as parameters for the models are discussed. The relations to the other evaluation methods such as the OWAS method and the NIOSH lifting equations are also briefly discussed.

key words:Work-related musculoskeletal disorders, Handling force, Electromyogram, Working posture, Biomechanical model.

原　邦夫，熊谷信二，山室　朗，小野真理子，武田繁夫， 野口淳平，中明賢二
蒸気・ガス状化学物質の職業性曝露濃度推定数理モデルの検証
Hara, K.et al.:Validation of mathematical models for predicting occupational exposures to vapors and gases used at the workplace.
労働科学,81（1）,16〜31,（2005） 　

化学物質のリスクアセスメントで重要な曝露アセスメントの方法として数理的な曝露濃度推定モデルを利用する方法がある。蒸気・ガス状有機溶剤を使用する職場で曝露濃度の測定結果と，６発生モデルと５分散モデルを組合せた決定論的な曝露濃度推定モデルの推定結果とを比較し，検証した。21の“単位作業”に対して曝露濃度推定モデルを適用したところ，曝露濃度推定モデルを適切に選択することによって様々な作業での曝露濃度の推定がおおよそ可能であることが示唆された。また，曝露濃度推定モデルの選択だけでなく，発生量の把握および発生源からの作業者の距離などが曝露濃度に大きく影響する因子とみられる結果であった。(図5・表9)（自抄）
キーワード：曝露評価，曝露濃度推定モデル，リスクアセスメント，職業性曝露，モデル検証

Kunio HARA (Work Environment Risk Research Group, Research Department, The Institute for Science of Labour), Shinji KUMAGAI (Osaka Prefectural Institute of Public Health), Akira YAMAMURO (Japan Chemical Industry Association (Kao Corporation at present), Mariko ONO-OGASAWARA (National Institute of Industrial Health), Shigeo TAKEDA (Mitsubishi Chemical Corporation ), Junpei NOGUCHI (Research Institute for Risk Communication on Chemicals) , Kenji NAKAAKI (Environmental Health Department, Azabu University) Validation of Mathematical Models for Predicting Occupational Exposures to Vapors and Gases Used at the Workplace
THE JOURNAL OF SCIENCE OF LABOUR,81（1）,16〜31,（2005）

　The assessment of occupational exposure levels is essential in evaluating health risks of workers exposed to chemicals at the workplace. Mathematical models predicting occupational exposure levels have recently been in use as one of practical exposure assessment methods. Several deterministic mathematical models presented recently which consist of a combination of 6 generation models and 5 dispersion models, however, have not been validated yet at the workplace. The objective of this paper was to validate the deterministic mathematical models by comparing the prediction results with the measurement results of occupational exposures to vapors and gases of organic solvents used at the workplace. 　Occupational exposure to vapors and gases and the conditions of workplaces were measured in a spray-painting workplace and two different materials preparation workplaces. The jobs were recorded by the "time-study" method that was a method of recording work done for the job every 30 seconds by following a targeted worker. A totally of 21 "unit jobs" which were separable from each other were selected for validation. 　By adopting 29 deterministic mathematical models to predict exposure levels of 21 "unit jobs", it was discovered that at least a deterministic mathematical model combining a generation model and a dispersion model was applicable to the prediction of occupational exposures to vapors and gases at each "unit job". It was found that not only the selection of a combined deterministic mathematical model but also the prediction of the amount of chemicals generated and the distance of a worker from a generation point affected occupational exposure levels. Further experimental studies for strict validation of 29 deterministic mathematical models in a room environmentally controlled, however, will be needed, because several unmeasured factors (generation rates, distance from generation points and other factors) which would affect occupational exposure levels were involved. key words:Exposure assessment, Exposure prediction model, Risk assessment, Occupational exposure, Model validation.

原　邦夫,中明賢二 国連GHS勧告を利用した職場での化学品管理の方法
Hara,K.et al: A chemical management system using the United Nations Globally Harmonized System of Classification and Labelling of Chemicals in the workplace
労働科学,81（1）,32〜48,（2005）

　国連GHS勧告を職場で有効活用するには，中身の理解はもとより，職場の化学品管理関係者の役割を明確にし，国連GHS勧告を活用した新たな化学品管理システムが必要である。細かな分類は専門家が担当すべきであるが，化学品管理関係者はラベル・SDSの内容と活用方法を理解すべきである。国連GHS勧告と日本の化学品管理の関連法令はその分類・表示方法が異なるため，現時点では職場の自主活動として化学物質マネジメントシステムに国連GHS勧告を組み込むことが望まれる。将来は，国連GHS勧告の危険有害性分類を機軸に様々な化学品管理の関連法令をつなぎ合わす化学物質管理基本ガイドラインの作成が行政に望まれる。(図8・表5)（自抄）
キーワード：国連GHS 勧告，化学物質管理，ハザード分類，ラベル，安全データシート

Kunio HARA (Work Environment Risk Research Group, Research Department, The Institute for Science of Labour) Kenji NAKAAKI (Environmental Health Department, Azabu University)
A Chemical Management System Using the United Nations Globally Harmonized System of Classification and Labelling of Chemicals in the Workplace
THE JOURNAL OF SCIENCE OF LABOUR,81（1）,32〜48,（2005）

　The requirements and conditions for the effective use of the Globally Harmonized System of Classification and Labelling of Chemicals recommended by the United Nations (UN GHS) in the workplace in Japan are discussed. In order to secure its appropriate use, it is critically important, in addition to understanding the content of the UN GHS, to define roles of persons concerned, establish a new chemical management system based on the UN GHS in the workplace, and clarify the differences in classification and labelling criteria between the UN GHS and the Japanese laws related to chemical management. Within the framework of the UN GHS, a system is established in which each chemical or mixture should be classified into one of 26 classes and further categorized as one of 77 categories according to the UN GHS criteria. Thus the chemical or mixtures should be attached with a label corresponding to one of the 77 categories, accompanied by a 16-item safety data sheet (SDS). The classification of chemicals or mixtures according to the UN GHS criteria is, however, so complicated that only specialists involved in chemicals classification should be in charge of the classification. Persons assigned to chemical management in the workplace except such specialists should understand the main points of the GHS and application of labels and safety data sheets to the workplace. There are several differences between the UN GHS and the Japanese laws in classification criteria and labelling methods related to chemical management. Further, it is necessary to incorporate the UN GHS in the chemical management system as part of an autonomous occupational health and safety management system in the workplace. Desirably, such a chemical management system should be an action-oriented system based on the UN GHS. When establishing such a system, the ILO "Chemical control toolkit" will be practical since it conforms to the UN GHS. As laws and regulations that govern the overall management of chemicals are yet to be formed in Japan, it is vital to formulate guidelines based on the UN GHS for chemical management subject to a combination of the relevant Japanese laws. key words:The United Nations Globally Harmonized System of Classifcation and Labelling of Chemicak management, Chemical management, Hazard classification, Labelling, Safety data sheet.

大西明宏
階段降段時のヒールクリアランスと主観量からみた危険度の低い歩行ピッチ
Ohnishi,A:Gait pitch with a low level of danger in stair descent taking into account the heel clearance and subjective evaluation 労働科学,81(2),65〜71,(2005)

　階段の降段時に焦点を当て，降段ピッチと危険度の関係をヒールクリアランスおよび5段階等間隔尺度の主観評定から明らかとすることを目的とした。被験者は若年健常男女それぞれ10名の計20名であった。被験者には踏面30cm，蹴上16cmの寸法で3段の階段を7条件の歩行ピッチで降段させ，それぞれの主観評定を測定した。ヒールクリアランスは3次元動作分析システムを用いて被験者の踵に貼付した赤外線反射マーカー位置を計測した後，踵軌跡から算出した。ヒールクリアランスは基準となる90歩/分以上のピッチで有意に短縮していた。また降段ピッチの増加に伴い危険感が増し，ヒールクリアランスと主観評定値に相関があった。若年健常者において降段時の歩行ピッチの増加が事故を引き起こす要素であること， 90歩/分が最も踵を引っかけ難く，危険感が少ないこともわかった。(図3,表1) （自抄）
キーワード：階段，歩行ピッチ，安全，ヒールクリアランス，主観評定

Akihiro OHNISHI（Kobe College of Medical Welfare Sanda Campus, Physical Therapist Course） Gait Pitch with a Low Level of Danger in Stair Descent Taking into Account the Heel Clearance and Subjective Evaluation
THE JOURNAL OF SCIENCE OF LABOUR,81(2),65〜71,(2005)

　The aim of this study was to investigate the relationship between the gait pitch of descending stairs and the degree of danger related to heel clearance and subjective evaluation. The subjects were ten healthy males and ten healthy females. The heel clearance was estimated on the basis of heel traces recorded. The subjects descended stairs of three steps with the gait pitch varying in seven conditions. Each stair had a size of 30 cm in the tread and 16cm in the riser. The gait pitch of 90 steps/min was used as the standard gait speed. The results for gait pitches of 50, 60, 90, 100, 120, 140 and 160 steps/min were compared with those for 90 steps/min. The heel clearance for these conditions decreased except for that for 90 steps/min. The decrease was especially notable in the fastest pitch. In this pitch, the heel clearance was at the minimum, and the subjective evaluation about the feeling of danger was at the maximum. This was related to the fact that descending at 90 steps/min was unlikely to hook the heel on nosing. There was almost no feeling of danger in the subjective evaluation.
Keyword :Stair, Gait pitch, Safe, Heel clearance, Subjective evaluation

西山勝夫
全身振動の生体影響研究の進歩と許容基準改訂の課題
Nishiyama, K: Review of studies on the effects of human exposure to whole-body vibration and the problem of updating the relevant exposure limits
労働科学,81(2),72〜84,(2005)

　日本産業衛生学会の許容濃度等の勧告に「全身振動の許容基準」が加えられたのは1975年である。当時,同基準が準拠したISO 2631は,その後改訂を重ねた。同基準の改訂の必要性を見極めるために,ISO 2631の1997年改訂以降,2004年5月迄のMedline及びJournal of Sound and Vibrationについて文献レビューを行った。 その結果,新たな知見が集積されつつあるものの,ISO 2631-1:1997あるいは予防のための明解な基準の制定に足りる医学的,科学的根拠はそれほど明らかではなかった。また,ISO 2631-1:1997に対する徹底的な批判論文への反論は見あたらない。 (図3)（自抄）
キーワード：全身振動，衝撃，生体力学，許容基準，腰痛

Katsuo NISHIYAMA（Department of Preventive Medicine, Shiga University of Medical Science） Review of Studies on the Effects of Human Exposure to Whole-body Vibration and the Problem of Updating the Relevant Exposure Limits
THE JOURNAL OF SCIENCE OF LABOUR,81(2),72〜84,(2005)

　In 1975, the Occupational Exposure Limits for Whole Body Vibration was included in the Recommendations of Occupational Exposure Limits issued by the Japan Society for Occupational Health. This recommendation was based on ISO 2631 that was subsequently revised repeatedly. To assess the necessity to revise the JSOH Occupational Exposure Limits for Whole-body Vibration, a scientific literature survey was undertaken by using the electronic databases of Medline and the Journal of Sound and Vibration during the period from 1997 when ISO 2631-1 was revised until May 2004. Text word searches of article titles and abstracts were conducted using the terms "whole-body vibration" and "WBV" and the adoption of the results show that medical or scientific evidences are not sufficient to justify ISO 2631-1 or to develop a clearer standard concerning the occupational exposure limits for whole-body vibration. There is no literature presented to argue against the critical reviews that questioned the validity of ISO 2631-1_: 1997. Furthermore, some literature discusses the reasons in favour of a departure from the traditional paradigm in view of the changing health risks induced by WBV under the reduction in exposure to whole-body vibration-exposure to the lowest possible level. Keywords: Whole-body vibration, Shock, Biomechanics, Exposure limits, Low back pain (LBP)

81巻3号

前原直樹
職場における循環器疾患予防のための労働と生活に係る対策
Maehara, N： The Measures Related to Conditions of Work and Life for Preventing Cardiovascular Diseases in the Workplace
労働科学，81（3），105〜124，（2005）

　労働関連の循環器疾患の発症や進展には労働と生活の諸条件に関連した負荷因子（例えば、長時間労働、頻回な夜勤、過ストレス、等）の大小もさることながら、その負荷によりもたらされる心身の負担およびそれに伴う疲労状態、前駆病態が欠くことができない。従って、職域での循環器疾患の予防策や循環器管理には、労働と生活関連の負荷因子と共に負担の軽減および疲労回復やストレス状態の改善策が必要となり、重要となる。そこで、職域での循環器疾患の予防策を勤務中の休憩や休日配置などによる負担軽減・疲労回復策などsの６事例で具体的に紹介した。（図9，表3）
キーワード；労働関連の循環器疾患，過労，睡眠・休養不足，慢性的な疲労・ストレス状態，労働と生活に係る予防対策

Naoki MAEHARA (Director, The Institute for Science of Labour)
The Measures Related to Conditions of Work and Life for Preventing Cardiovascular Diseases in the Workplace
THE JOURNAR OF SCIENCE OF LABOUR，81（3），105〜124，（2005）

　In occurrence and development of work-related cardiovascular diseases, individual conditions resulting from the stress associated with work and life（for example, long working hours, frequent night work, and excessive work stress, and so on）play vital roles. These conditions include the strain and fatigue induced by the stress as well as symptoms and signs preceding the suffered diseases. 　In occupational health, the control of excessive work becomes urgent, and over-fatigue conditions and loss or lack of sleep are listed as typical factors. At the time of the occurrence and development of myocardial infarction, cerebral hemorrhage or subarachnoid hemorrhage, it is generally shown that findings that suggest the relationship between over-fatigue conditions and loss of sleep are observed in an increasing number of cases. 　In other words, for preventing the incidents of cardiovascular diseases in the workplace on the basis of the previous findings, it becomes important to take measures for supporting recovery from fatigue and reducing the work strain, in addition to the reduction of the stress. 　Effective preventive measures in the workplace in this regards are discussed by presenting six examples. These examples indicated the usefulness of such measures in reduction of the strain and acceleration of the recovery from fatigue during the rest breaks and holidays.

Key words: Work-related cardiovascular disease; Over-fatigue condition; Loss or lack of sleep and rest; Chronic process of fatigue and strain; Preventive measures associated with work and life

黄河、三澤哲夫、肝付邦憲 中国紡績業における女性従業員の労働負担に関する調査研究
He Huang, Misawa, T, Kimotsuki, K： Investigative Study of Burdens and Fatigue of Working Women in the Chinese Textile Industry
労働科学,81（3）,125〜133,（2005）

　中国では、女性は結婚や出産でも仕事を辞めず継続就労することが一般的である。就労女性の作業負荷と生活実態を把握するために、本研究では、紡績工場で勤務する女性従業員32名を対象として、「自覚症しらべ」、「生活時間調査表」などを用いて、質問紙調査を行った。この結果、疲労感は職種によって異なるが、終業時が始業時より大幅に増加した。帰宅後8割以上の女性が家事をする実態が見られた。今後、女性が仕事と家庭を両立させるため、勤務時間の短縮や労働環境の改善など改善策の提案が必要である。（図３）（自抄）
キーワード：女性労働者，紡績工場，自覚症しらべ，生活時間，改善

He HUANG（Graduate School of Management Engineering, Chiba Institute of Technology）, Tetsuo MISAWA (Chiba Institute of Technology), Kuninori KIMOTSUKI (Chiba Institute of Technology)
Investigative Study of Burdens and Fatigue of Working Women in the Chinese Textile Industry
THE JOURNAR OF SCIENCE OF LABOUR,81（3）,125〜133,（2005）

　In China it is common for women to continue working after marriage and childbirth. The purpose of this study is to examine conditions of fatigue of working women and their double burdens of work and family. This study was carried out in a textile factory in Jiangsu Province， China. The factory was mainly composed of three departments: warp-starching， weaving and finishing. The working team formation and working time arrangements varied between different departments. A questionnaire was distributed to 50 female workers in the three departments, and 32 of them replied. The contents of the questionnaire included their attributes, questions of the Todai Health Index and asheet for recording the time spent for daily life activities. They were also asked to fill in a survey sheet of Subjective Fatigue Symptoms and that of Tired Body Parts three times on a working day. 　The results concerning subjective fatigue symptoms were shown that the average rates of those complaining of sleepiness, indisposition, 1anguidness and blurred vision were higher after work than before work, especially with respect to sleepiness and blurred vision. Though the tired parts were different according to the type of occupation, the workers complained frequently of the lower limbs, the back and eyes as tired parts. The records of time allocations of daily life, activities showed that including commuting time, the total time spent at work was over 10 hours on the average on a working day. It was longer than the standard working time. After work about 80 percent of the subjects had to do substantias housework. The average time spent in doing housework, child-care and nursing was over 3 hours. The results of the study revealed that there was a strong need to improve both the working environment and ergonomic conditions in the textile factory. It was also suggested that in order to cope with work and family, a practical strategy should be established to shorten working time and reduce workload for working women in China.

Key-Words: Female worker, Textile factory, Subjective fatigue symptoms, Daily life, KAIZEN (Improvements)

佐々木司, 鈴木一弥, 久保智英, 松元 俊, 松隈洋平
２連続模擬夜勤時にとる仮眠の睡眠構築に及ぼす影響
Sasaki, T et al. : Effects on sleep architecture of naps taken on the simulated two-consecutive night shifts
労働科学, 81（4）, 161〜168, (2005)

8名の男子大学生を対象として2連続模擬夜勤時の夜勤2夜目にとる2時間の仮眠が，夜勤明けの睡眠に及ぼす影響を実験的に検討した。その結果，仮眠はその後の昼眠の睡眠段階4を有意に減少させ，覚醒を有意に増加させた。しかし仮眠に昼眠の最初の4時間を加えた睡眠（6時間）を，仮眠なしの昼眠（6時間）と比較した結果，睡眠段階4と覚醒に有意差は示されなかった。したがって仮眠がその後の昼眠の質を低下させたことは，仮眠の負の効果ではなく，仮眠が昼眠の質を先取りしただけであった。また仮眠は，夜眠の睡眠段階4を有意に増加させた。したがって2連続夜勤時に夜勤ごとにとる仮眠は，睡眠構築の点から推奨されてよい。（図3・表2）（英文）

Tsukasa SASAKI（Work stress research group, The Institute for Science of Labour）, Kazuya SUZUKI（Human-technology interaction research group, The Institute for Science of Labour ）, Tomohide KUBO（Health Science of Life, work and Environment, Department of Environmental Health Science and Health Promotion, Graduate Scholl of Medical Science, Nagoya City University）, Shun MATSUMOTO (Work stress research group, The Institute for Science of Labour ), Yohei MATSUKUMA (Work stress research group, The Institute for Science of Labour ),
Effects on sleep architecture of naps taken on the simulated two-consecutive night shifts
THE JOURNAR OF SCIENCE OF LABOUR,81（4）,161〜168,（2005）

We studied the effects of a two-hour nap taken during the second night of two consecutive night shifts on the sleep architecture of subsequent daytime and nighttime sleep. Eight healthy male university students participated in simulated night shifts under two conditions: one involving napping during the first night but no napping during the second night (the One-Nap condition) and another involving napping on two consecutive nights (the Two-Nap condition). There were no statistical differences in sleep variables during the first night shift including subsequent daytime sleep. On the other hand, the length of stage 4 sleep was significantly decreased and the length of stage W (wakefulness) significantly increased during daytime sleep (six hours) after the second night shift under the Two-Nap condition, compared to daytime sleep (six hours) under the One-Nap condition. However, a comparison of the combined sleep period (six hours) of a nap (two hours) and the first four hours of daytime sleep under the Two-Nap condition versus daytime sleep (six hours) under the One-Nap condition showed no statistically significant differences in the amounts of stage 4 sleep and stage W between the two conditions. Based on these results, we speculate that the widely-credited negative effects of a nap taken during a night shift on subsequent daytime sleep may not mean the negative effects of napping, as is commonly understood, but the preemption of daytime sleep quality. In addition, a nap in the second night of the simulated night shifts significantly increased stage 4 sleep during subsequent nighttime sleep. Therefore, we concluded that a two-hour nap taken on each of two consecutive night shifts should be recommended for night workers from a perspective of sleep architecture.

Key words: Two-consecutive night shift, Nighttime nap, Sleep architecture, Countermeasure to night shift, Experimental study

元橋　綾子，落合　博志,吉田　雄太，菊地　敦，斉藤　良夫
救急出場件数の増加が救急隊員の勤務中の生活活動時間に及ぼす影響に関する調査研究
Motohashi, A：How times for meals, rest Periods and naps on duty of ambulance personnel per one-day shift decrease, with increases in the number of ambulance runs
労働科学, 81（4）, 169〜181, (2005)

T自治体の消防組織で一昼夜勤務に従事する救急隊員について、１日の勤務中の食事、休息、手洗い・シャワー、仮眠の４生活活動の所要時間が1日救急出動件数の増加とともにどのように減少するかを調査した。のべ224名のデータが分析された。出動件数の異なる５つの群をつくり、それらの群に関する分散分析の結果、食事、休息および仮眠の３生活活動の所要時間は出動件数の増加とともに有意に短縮した。しかし、多重比較の結果では、休息、仮眠、食事の順に、有意な相違があった出場件数群が異なっていた。１日の勤務遂行にとってより不可欠な生活活動は、より多くの出場件数でその所要時間の間に有意差が現れることが示唆された。（表３）
キーワード：救急隊員；出場件数；一昼夜勤務制；生活時間調査；仮眠時間

Ayako MOTOHASHI（Health Care Office, Personnel Division, Tokyo Fire Department）， Hiroshi OCHIAI（Research Division 4, Fire Science Laboratory, Tokyo Fire Department）， Yuta YOSHIDA（Research Division 4, Fire Science Laboratory, Tokyo Fire Department）， Atsushi KIKUCHI（Omori Fire Station, Tokyo Fire Department）， Yoshio SAITO （Emeritus Professor, Chuo University）
How times for meals, rest Periods and naps on duty of ambulance personnel per one-day shift decrease, with increases in the number of ambulance runs
THE JOURNAR OF SCIENCE OF LABOUR,81（4）, 169〜181, (2005)

The purpose of the study was to clarify relationships between the number of ambulance runs per day by ambulance parties and times spent by ambulance personnel for their four kinds of personal activities on duty, i.e., having three meals, washing the face/hands and showering, resting, and napping in a sleeping room at night. Their duty hours per shift were 24h and 10min from 08:30 a.m. until 08:40 a.m. of the next day. Among the total 207 ambulance parties of the Tokyo Fire Department in 2002, 10 parties were randomly selected, each pair of which belonged to one of the following five groups: 10 parties with the largest number of ambulance runs (GL), parties with 3500±50 runs (G3500), those with 3000±50 runs (G3000), those with 2300±50 runs (G2300), and 10 parties with the smallest number of runs (GS). The levels of 3500, 3000 and 2300 runs per year have been set by the Fire Department as standards classifying ambulance parties according to ambulance runs per year. A time-budget study was performed for seven successive days in February 2003. Two hundred and thirty ambulance service workers participated in the study. They were given a time-budget sheet each day during the study period and were asked to fill up the sheet mentioning every 10 min for what tasks or for what personal activities on duty they spent their time using 18 categories printed on the sheet. These categories were an ambulance run, 3 run-related tasks to be performed after a run in their fire offices, 10 tasks in which they were obliged to take shares during their duty hours and 4 personal activities mentioned above. Data for 224 persons of the participants were analyzed in the study. As for the four personal activities performed by the ambulance workers during their one-day duty, the results showed that the average times for all the groups were 1h 14min for meals, 16min for washing the face/hands and showering, 1h 21min for resting, and 4h 09min for napping. It was found that the average times for meals and for naps were shorter by 46min and 2h 31min, respectively, than corresponding times allocated according to the working time regulations of the Fire Department. The results of ANOVA comparing between the five groups revealed that the times for meals, rest periods and naps on duty of the ambulance personnel decreased statistically significantly as the number of ambulance runs per day increased. The results of multiple comparison tests showed that two subsequent groups in which the average times for these personal activities were significantly different from each other were GL and G3500 for meals, G3500 and G3000 for naps, G3000 and G2300 for rest periods. This meant that the more indispensable a personal activity on duty for completing a one-day duty of the ambulance work was, the more significant decrease in the time spent for the personal activity was noted with the increasing number of ambulance runs. The average sum of times spent for doing all of the four personal activities on duty for the five groups from GL to GS were 5h 37min, 5h 18min, 7h 02min, 8h 41min and 8h 34min, respectively. The results of ANOVA showed that there were statistically significant differences in the average times between the five groups. The results of multiple comparison tests revealed that there were significant differences between G3500 and G3000, and between G3000 and G2300. There were no significant differences between GL and G3500, and between G2300 and GS. It is suggested that five hours and a half may be the minimum time that an ambulance worker may need for doing all of the four personal activities on duty during their duty hours when the number of ambulance runs exceeds 9.6 per day, i.e., 3500 per year.

Key words：Ambulance men; Number of ambulance runs; 24h duty; Time-budget study; Napping hours


岩佐卓也
男女賃金差別と年功賃金 森ます美『日本の性差別賃金』の検討
Iwasa, T : Sex-based wage discrimination and seniority-based wages
労働科学, 81（4）, 182〜197, (2005)

日本の年功賃金は「属人基準」であり、仕事に対応していないがゆえに性差別的であるとの見解は今日広く共有されている。しかし、代表的な男女賃金差別是正運動を検討するならば、是正の基準または根拠としての年功賃金の重要な役割が明らかとなる。属人基準か仕事基準かという問題は、男女賃金差別の強弱とは別次元の問題であり、年功賃金は本質的に性差別的との主張は、実証的にも理論的にも誤っている。また、この年功賃金に対する誤った評価によって、成果主義が歓迎されるという危険性も存在する。本稿は、以上の点を森ます美『日本の性差別賃金』に即して検討した。（図5）
キーワード 年功賃金；男女賃金差別；人事考課；家族賃金；ジェンダー視点

Takuya IWASA（Faculty of Human Development ,Kobe University）
Sex-based wage discrimination and seniority-based wages
THE JOURNAR OF SCIENCE OF LABOUR,81（4）, 182〜197, (2005)

Today the opinion is generally shared that seniority-based wages in Japan are built on personal attributes rather than on work performance and therefore conducive to gender-based discrimination. However, when we examine typical movements aiming at reforming gender-based wage discrimination, we recognize an important role played by seniority-based wages as valid criteria or justification for advancing the ongoing reform. Therefore the issues as to whether wages are determined by personal attributes or by work performance should be considered to belong to dimensions different from those of the issues as to whether gender-based discrimination is strong or weak. Accordingly, the opinion that seniority-based wages are essentially gender-discriminative does not hold true empirically and theoretically. We should note that this misunderstanding concerning seniority-based wages may lead to a non-evidenced conclusion that pay-for-performance systems are generally desirable. These aspects are examined with reference to the discussion by Masumi Mori concerning gender-based wage discrimination in Japan.

Key word : Seniority-based wages；Sex-based wage discrimination；Personnel rating；Family wage；Gender viewpoint