The antenatal physio therapist said to me just sitting still on a ball whilst watching tv can tone your tummy as you are constantly having to keep your balance, so I started with that, and I did my nip and zip exercises and pelvic floor exercises whilst sat on it rather than on a normal chair. I've added a small rocking backwards and forwards with my pelvis motion now I have got my confidence up, but I am still not quite at the bounce stage yet!