Hi Kelli,Daniel and everyone else - I've been doing FB's great HIIT workouts for about 2.5 yrs. In November I suddenly got an agonising back problem - an inflamed joint on the L4/L5 vertebrae & a facet joint cyst, which compressed the root of the sciatic nerve. I couldn't sit, stand, lie down or walk for 2 months. Gradually I recovered. Which of your workouts can I do? Would like to do cardio & HIIT but wary.