Optimal training intensity?
 

How do you know when you're training optimally? By "training optimally", I mean you're making the biggest potential gains, getting enough rest and recovery, and stressing your body enough but not too much, while at the same time balancing other requirements like proper nutrition, injury avoidance and healing, weight loss and time constraints.

It's different every day... It depends upon your existing fitness level. Someone who's in shape and have had 2-3 seasons of racing may need to do 20-30 sprints and 4-5 days of intervals a week combined with 120 minutes of hillclimbs. A beginner may only be able to handle 1/10th of that.

Track your training, write it in a journal and do a standardized time-trial once a week. When you're overtrained, you'll have continual fatigue and your TT speeds will cease to increase. Look at your previous week's training-log and back off a bit.

You pay a coach to think about that for you, and the if you really really care, you pay to have him around full time.