Mental and Physical Fatigue 1 



able to work it again. Further, when no movement can be made 

 with the weight of say 5 kilograms, another considerable amount 

 of work may be done if the weight is reduced to 4I kilograms. 



Thus we seem to get fatigue to particular conditions. An 

 important fact shown by the experiments is that, when a muscle is 

 fatigued, even light work is more injurious than heavy work done 

 by a fresh muscle. This shows the foolishness and waste, from a 

 business point of view, of working labourers beyond the point of 

 fatigue. 



B. Relation between 

 Muscular and Mental Fatigue. 



The popular idea is that we get rid of mental fatigue by 

 means of muscular exercise. Stated thus, the idea is false. On 

 physiological grounds the presence of fatigue products, whether 

 caused by Mental or Physical work, would be likely to hinder 

 muscular or mental work as the poisonous products spread over 

 the whole system. Slides were shown demonstrating the great 

 effect of vigorous mental work on muscular work ; in some 

 cases the effects of severe mental work continued to result in 

 inferior muscular work for several days, hence in the organisation 

 of school work it is desirable that a period of rest should follow 

 vigorous muscular games or drill. I'he speaker had found that 

 among large numbers of training college students gymnastics were 

 more fatiguing for mental work than mental work of another 

 type. 



C. Mental Fatigue. 



Various methods of testing mental fatigue were described, 

 including simple tests which could be applied by teachers in the 

 schools. The effects of pauses in the work were also shown on 

 the basis of experimental tests and the important distinction 

 between boredom and fatigue was emphasized. Indeed, easy 

 work has been found to be more fatiguing in the long run than 

 hard work, owing to the onset of boredom. A theory of fatigue 

 was suggested, namely, that interest is the key which unlocks the 

 normal store of energy. Where there is lack of interest theri? is 



