Acid, I think it's important for you to make you you're fully recoved from the throat infection before you start. I expect you were off for more than a week or so. Then you need to get your body (& heart) used to the bike again for a day or two. The muscles need to get into the habit of going round and round. A couple of easy to medium intensity rides spinning the legs until you feel better. You can't really do high intensity training properly without having done lots of low intensity endurance base work. If you have an adequate base then do some shortish (45mins - 1hr15) consistently hard (80 - 90%) rides. intervals can either be longish and slighlty lower in intensity or shorter higher intensity. eg. Increase HR up to 85% for 5 minutes and then recover to 60% for 5 minutes and repeat a number of times. Or increase HR to above 90% for a minute or 2 and recover to 60%. Remember to warm up at 60% for 10 minutes before hard rides and cool down for 10 minutes after. And stretch those muscles.