Jun 9, 2014 While doing dumbbell flys tonight I had a sudden and complete loss of power my arm felt like it just collapsed? Folded down and I nearly ended up with a dumbbell in the face? Wtf why? I had all my lymph nodes removed in left breast and arm pit about 5 years ago this wouldn't be it would it? I mean lymph is just a filter system frankly but I've no injury so I can't understand it! It's not the first time, once before during bench press ! Any ideas?