"Training is a case of stress management.  Stress and rest; stress and rest."
                                                       - Brooks Johnson  

It is important for every coach and athlete to know what the purpose of each day’s workout is, and to remember that the goal of training is to provide the least stressful stimulus to elicit the desired adaptation.  Too often I see athletes running workouts faster than they should, because they think faster is better.  But that way of thinking is wrong.  Smart training is about optimization.

The training of distance runners can be divided into the following categories:     

1. Long, Slow Distance (LSD) Runs: Easy, comfortable runs at approximately 70-75% max heart rate (about 1.5-2 minutes per mile slower than current 5K race pace).
Purpose: To increase the number of capillaries perfusing the muscle fibers, increase mitochondrial density, increase red blood cell and hemoglobin concentration and total blood volume, increase the ability of muscles to extract oxygen from the blood, and enhance the ability of the muscles to store more carbohydrate. 

2. Lactate Threshold Workouts: The lactate threshold (LT) is a physiological variable that demarcates the transition between exercise that is purely aerobic and exercise that includes significant oxygen-independent (anaerobic) metabolism.  LT can therefore be considered the fastest speed that you can sustain aerobically.  These workouts are “comfortably hard” runs at LT pace (about 85-90% max heart rate, or about 25-30 seconds per mile slower than current 5K race pace).  I typically use four types of LT workouts with my athletes:

• Continuous runs at LT pace, starting at about 3 miles and increasing up to 7-8 miles for marathoners.

• Intervals run at LT pace with very short rest periods, such as 4 x 1 mile at LT pace with 1:00 rest.

• Short intervals run at slightly faster than LT pace with very short rest periods, such as 2 sets of 4 x 1,000 meters at 10 seconds per mile faster than LT pace with 45 seconds rest and 2:00 rest between sets.

• Long runs (12-16 miles) with the last 3-4 miles at LT pace (I only include this workout with marathoners).

Purpose: To raise the lactate threshold to a higher percentage of your VO2max or, in other words, to increase the speed at which your LT occurs.  This allows you to run faster before you fatigue because it allows you to run faster before anaerobic metabolism begins to play a significant role. 

3. Intervals:
Long “Aerobic” Intervals: Hard runs of 2-5 minutes at 95-100% max heart rate (about 3K race pace for highly trained runners) with relatively short recovery periods that are typically equal to or slightly less than the time spent running.
Purpose: To increase the maximal amount of oxygen the muscles can consume per minute (VO2max).  This is accomplished by increases in the size of the heart's left ventricle, venous return (the return of blood to the heart), stroke volume (the volume of blood pumped out of the left ventricle with each beat), cardiac output (the volume of blood pumped out of the left ventricle each minute), and contractility (the ability of the heart muscle to contract forcefully).

Short “Anaerobic” Intervals: Fast runs of 30 seconds to 2 minutes with recovery periods that are typically 1-2 times as long as the time spent running.
Purposes: To increase speed by recruiting fast-twitch muscle fibers and to enhance buffering capacity of muscle acidosis.

Other Types of Training:

Hills: Hard runs up a hill with a jog or walk down as recovery.
Purposes:To increase strength and power of quadriceps, calves, hip flexors, and gluteus maximus muscles and to improve running economy (the amount of oxygen used at a given pace). 

Fartlek: Swedish term meaning “speed play.”  Continuous runs during which you pick up the pace at specified times.  Distances, intensities, and recovery periods may vary within the same workout.  Could use time or landmarks to determine when to pick up the pace and when to slow down.
Purposes: To learn different paces, work on team tactics, and include variety and fun to the training.