why do our muscles get tired

today for our reading we had to make a flip grid about what our work why do our muscles get tired? we had to talk to Mr Wong about what we had to do. so we had to read a artical about why do our muscles get tired? so we had to find out words we dont know and find the meaning in our video we are suppost to say 3 words that we din'nt know before and now know right now.