I've had BFS for 1 year and yes I experienced very large, hard, and frequent jerks during the 1st 8 months in my gluts, lats, deltoids, and pectoral muscles. Strong enough to move the entire joint. I still experience them; although at a reduced frequency. The fasciculations, twitching, buzzing, and vibrations are pretty much non-stop somewhere in my body--- even during sleep. I also experience rippling "myokemia" with tremor in my muscles during partial contraction. I've had two EMG's and both were clean. It's annoying (to say the least) but I've learned, and continue to learn how to live with it.