Feuerstein M, Armstrong T, Hickey P, Lincoln A
Department of Medical and Clinical Psychology, Uniformed Services University of the Health Sciences, Bethesda, Md. 20814, USA.
J Occup Environ Med. 1997 Dec;39(12):1144-53. doi: 10.1097/00043764-199712000-00008.
This case-control study assessed whether office workers who report more severe levels of musculoskeletal symptoms of the upper extremities demonstrate higher levels of keyforce in comparison to controls with less severe symptoms. Office workers reporting working on computer keyboards for four hours per day were classified as cases or controls based upon a median split on a Composite Symptom Severity score (cases = 23, controls = 25). Keyboard force and keying rate were measured during a 15-minute keyboarding task. Measures of task-related discomfort, muscular fatigue, pain, upper extremity symptoms, psychological distress and force were collected at baseline, post-keyboard task, and recovery. Ratings of perceived effort and task credibility were also obtained. Measures of work demands, perceived job stress, and upper extremity strength and flexibility were also collected. The results indicated group equivalence on reported work demands and upper extremity strength. Cases were more likely to receive a medical diagnosis of upper extremity cumulative trauma disorder, awaken from sleep due to symptoms, report higher levels of pain during work, experience greater impact of pain on function, and report higher workload pressure and lower support. Cases generated significantly higher keyboarding forces than controls, although both groups produced forces well above that required to operate the keyboard (4-5 times activation force). Cases reported higher levels of upper extremity symptoms and discomfort than controls, and these measures were highest after the keyboarding task for both groups. No significant correlation between keyforce and key rate was observed in either group. Results suggest that generation of excessive force while working on a computer keyboard may contribute to the severity of upper extremity symptoms. Clinically, the findings suggest that evaluating how an individual worker performs keyboarding tasks, or his or her workstyle, may be helpful in the management of these symptoms and disorders.
这项病例对照研究评估了与上肢肌肉骨骼症状较轻的对照组相比，报告上肢症状更严重的办公室工作人员是否表现出更高的按键力度。根据综合症状严重程度评分的中位数分割，将报告每天在电脑键盘上工作4小时的办公室工作人员分为病例组或对照组（病例组=23，对照组=25）。在15分钟的键盘操作任务中测量键盘力度和按键速率。在基线、键盘任务后和恢复阶段收集与任务相关的不适、肌肉疲劳、疼痛、上肢症状、心理困扰和力度的测量数据。还获得了主观用力程度和任务可信度的评分。同时收集工作需求、感知到的工作压力以及上肢力量和灵活性的测量数据。结果表明，两组在报告的工作需求和上肢力量方面相当。病例组更有可能被诊断为上肢累积性创伤障碍，因症状从睡眠中醒来，报告工作期间更高程度的疼痛，经历疼痛对功能的更大影响，并报告更高的工作量压力和更低的支持度。病例组产生的键盘力度明显高于对照组，尽管两组产生的力度都远高于操作键盘所需的力度（激活力度的4 - 5倍）。病例组报告的上肢症状和不适程度高于对照组，并且两组在键盘任务后这些测量值都是最高的。两组中均未观察到按键力度与按键速率之间存在显著相关性。结果表明，在使用电脑键盘工作时产生过大的力度可能会导致上肢症状加重。临床上，这些发现表明评估个体工作人员执行键盘任务的方式或其工作风格，可能有助于管理这些症状和疾病。
