It's likely different with each person but I can give you an example for me. I was doing some weight training (tricep extensions) and the following day it felt like someone was stabbing my triceps with a knife. Lasted a couple of days. I also try to walk 4 to 5 miles each morning. This can cause some cramping in my quads but it usually doesn't last more than an hour or two. Just pay attention to your body as you are exercising. If you feel muscle groups getting tight or cramping, then you should stop and scale it back a little. With respect to twitching, there are so many things that can set it off and you never know what could trigger hotspots (areas that will twitch non-stop 24/7).