Insanity workouts made my knee pain & numb for a period of time so i stopped working out for a month doesn't hurt now but feels odd. is this serious?

Good Question: The insanity work out is hard on knees. The fact that your knee is feeling better is a good sign that no serious damage was done. I suggest avoiding this type of work out in future. Instead, try strength training using weights. When training your legs, keep the amount of weight light and do multiple sets (3 or 4) of high reps (20 reps). This will strengthen you knee without causing injury.

No: Certain exercises put increased strain on the soft tissue structures around the knee. You can end up with collateral ligament strains tendinitis and sometimes you can injure your meniscus. You can start your workouts again but gradually increase your activity level to your tolerance. Some workout programs cause significant increase stresses on the knee like zumba and you have to be careful.