Is breakdancing bad for my muscles?

Patient: I’m into break dancing, especially popping and locking and dimestopping (basically just variations of the robot, very stop and starting type of dances). To do this dance style requires heaps of muscles tensing especially in the pecs, shoulders and arms. In doing this, I keep my my arms and upper body tensed and hold this tense for 10 to 20 mins, whilst moving only my joints. After i do this though, my muscles become really sore, and I heard somewhere that you shouldn’t tense your muscles (like in showing off your biceps) so if this is true, holding a tense must be really bad. But im not sure if thats actually correct. Thanks for your help!! 🙂