I have begun to experience a total and sudden loss of muscle strngth in my legs, causing me to fall. I am a Healthy 73 yr old male with no health issues until now. This condition began a few weeks ago and occurs an average of 3 times per week. I have identified one suspected trigger. Deep coughing with forceful exhaling can sometimes bring it on. Other than that, it just seems to happen randomly. I had an MRI, but no problems were identified. There is no pain. The episodes last from 5-30 seconds, then all is back to normal for the remainder of the day. It has been suggested I have an EMG, but I feel it would show nothing unless I had an episode during the test (Highly unlikely). Any testing recommendations? My primary doctor is perplexed...me too! Jerry