Rest is good.

I over trained.
Simply put, I put more stress on my system than the amount of rest and nutrition can make up for. I use a system to calculate the total workload I put on my system; by multiplying the minutes exercised times the heart rate zone.
I.E.
Zone 1 = 15.75 minutes = 15.75 workload
Zone 2 = 73.75 minutes = 147.50 workload
Since everyone has different heart rate zones, this system has a certain reliability to it.
By adding up the total workload for the week, you can have a number to assign to the training you've done. Typically, though I calculate the workload, I don't spend much time looking at the progression of those numbers. Looking back at them, I can correlate those workload numbers to how tired I am. Below is a breakdown of the workload (cycling only) of my training since the first of January:
Week 1 -85
Week 2 -159
Week 3 -175.8
Week 4 -150.55
Week 5 - 465.25
Week 6 -143
Week 7 -692.9
Week 8 -206
Week 9 -345.5
Week 10 -143
Week 11 -693.4
Rather inconsistent, if I do say so myself.
Back to over training. The last few workouts of Week 11, last week, I was unable to get my heart rate up as I had in previous trainings. General disinterest in turning the cranks over. I'd pushed too hard, and I knew it. With that in mind, I skipped my strength training on Monday and the scheduled hour of cycling training on Tuesday.
The result?
For a similar ride, I rode two miles farther, with a average speed of one mph faster.

Rest is good.
Rest in important.
MtM