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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An analysis was made of parameters of the EMG contraction pattern of the soleus and the tibialis anterior muscle in normal test subjects. Constant isometric contractions were consecutively executed with both muscles during 60 sec under standardized conditions. The EMG was derived with surface electrodes, then converted analogue to digital and analyzed with the aid of a PDP 8/I computer. Values measured were tension, integrated amplitude, peak-to-peak amplitude and number of peaks. The fluctuations in tension exerted (coefficient of variation) were more marked in the tibialis anterior than in the soleus muscle. The difference between males and females in tension exerted was different for different muscles. The EMG pattern showed significant intermuscular differences, as did the fatigue phenomena. One of the causes is the ratio between tonic and phasic motor units. The same applies to intermuscular differences in fatiguability. Different muscles may dominant in different individuals. The above observations can explain the great range of variation in normal values. Comparative clinical studies will require a cataloguing of normal values for all muscles. This study can contribute to this.
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PMID:Automatic digital analysis of the EMG during standardized flexion and extension of the foot. 115 15

The authors report here the results of evaluation experiments designed to explore the effect of viewing distance on visual fatigue. Two kinds of visual content (normal content and content likely to cause visual fatigue) were used by means of physiological measurements of subject responses while viewing a 42-inch PDP display, followed by psychological evaluations in the form of post-experiment interviews. Both experiments showed that visual fatigue reached a minimum at a distance of 3 to 4 times the height of the display (3-4H; 165 cm-220 cm) and that sympathetic nerve activity peaked at around 3H. These results indicate that the ideal viewing distance for minimal visual fatigue and a closer feeling of involvement might be at around 3H.
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PMID:Evaluation of the effect of viewing distance on visual fatigue in a home viewing environment. 2192 86