Schmidt A J
J Psychosom Res. 1985;29(6):639-45. doi: 10.1016/0022-3999(85)90073-x.
An experimental group of 39 chronic low back pain (CLBP) patients and an equal number of control subjects matched for age and sex were tested with a standardized back stress physical test. The subjects were given no indication of the performance expected and no feedback was given during the test. The test was repeated with a high frame of reference and feedback offered to the subjects. In the latter condition the control group improved their performance in contrast to the CLBP group. The poorer performance of the CLBP patients in both conditions was unrelated to pain increase, post-test pain level or poor physical condition. However, there is a clear relationship between performance and pre-test pain level, especially in the feedback condition. In this condition, it also seems that increasing pain level during the test is used as a 'rationalization' for the built-in failure experience. Compared to the control group the CLBP patients were less able to estimate their physiological level of exertion and were inclined to overrate their actual effort.
一个由39名慢性腰痛（CLBP）患者组成的实验组和数量相等、年龄与性别匹配的对照组接受了标准化背部压力体能测试。测试前未向受试者说明预期表现，测试过程中也未给予反馈。之后以高参照标准重复测试并向受试者提供反馈。在后一种情况下，对照组相比CLBP组改善了他们的表现。CLBP患者在两种情况下表现较差均与疼痛加剧、测试后疼痛水平或身体状况不佳无关。然而，表现与测试前疼痛水平之间存在明显关系，尤其是在有反馈的情况下。在这种情况下，测试期间疼痛水平的增加似乎也被用作对内在失败体验的“合理化解释”。与对照组相比，CLBP患者更难以估计自己的生理 exertion 水平，并且倾向于高估自己的实际努力程度。 （注：exertion 在这里根据语境大致可理解为“用力程度”，但原文中这个词表述不太清晰准确）
