It is believed that eccentric movements induce muscle damage or tears within the muscle belly.

通常认为反常运动会引起肌肉创伤以及肌腹内部撕裂。

And they timed the characters' breathing to their dialogue and at the same time let the characters' belly muscles and diaphragm tighten so it would really like they were letting out air while talking.

他们同时对动物们对话时的呼吸进行了校对，让动物们的腹肌和横膈膜收紧，这样一来，他们说话的时候就会真的像在呼气一样。