VDOT

VDOT is at the heart of Jack Daniels Running Formula. Jack Daniels' plans are based around calculating the ideal training paces based on previous race performance. The faster you are in a race, the faster you need to train. Jack Daniels book provides tables of race performances to use to look up a VDOT number. This VDOT number is then used to look up training paces for his plans. I would recommend reading Jack Daniels Running Formula, but there are online VDOT Calculators to make things easier for you.

For the curious, VDOT is based around the fact that your race performance is linked to your velocity at your maximum aerobic capacity. Aerobic capacity is defined by the maximum (max) volume (V) of oxygen (O2) you can absorb. This is written as VO2max, and the velocity at VO2max is vVO2max. VDOT is the VO2max that would result in the given race performance assuming a 'normal' running efficiency. Having a VDOT of 55 does not mean you have a VO2max of 55. Your VO2max could be much higher, but you are inefficient or much lower but you are efficient. Either way, VDOT gives a single number to define your aerobic fitness.