Hi There,
I would recommend you to go for Get Smart GYM situated in Swannah City in 13-D next to Rabi Lawn I guess
GYM is mediocre but there is one trainer "Shani Bhai" who is quiet a pro in his approach and I have madea tremendous progess under his training!
You can visit their website, search for "get smart chain of gyms in karachi" on google for their address
Happy Healthy Living