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1·The distance of the gap needs to be between the outer limits of boredom and overstrain according to Iser.

根据伊瑟尔的观点，这种差距应该在无聊和过度劳累的外部界限之间。

2·Most muscle and spinal injuries are from overstrain.

大多数肌肉损伤和脊椎的问题都来自用力过度。

3·Both endopathic factors and exopathic factors might cause fatigue, but overstrain was the main etiology.

内因、外因均可导致疲劳，但以内伤尤其过劳为主要病因。