Answered by Bob Glover on Monday, June 1, 2009
It's common for a casual runner to get to the point where he or she just can't go any faster. This most likely occurs because you do all your training aerobically—that is, at a comfortable pace. But when you race, you try to push your body to run at a pace that is not comfortable and that leads to a buildup of lactic acid. Once you go beyond a certain point in lactic buildup (called your lactate threshold) the result is severe muscle fatigue and the inability to hold pace. You need specific training to improve your body's tolerance for faster paces—that is, you need to add speed training on a weekly basis. Speed training makes you a stronger, faster, more efficient runner.
What is speed training? Simply stated, it consists of workouts run at faster than your comfortable pace. Speed training is based on a simple formula: Run at your present race pace or faster for segments that are much shorter than your race distance, with recovery breaks in between to minimize the stress on the body. For an 8-minute-miler aiming to run faster in a 5K, the goal range would be about a 7:00-to-7:45-minute pace, depending on the length of the speed segments. One speed training session per week is enough for most runners.
There are four basic types of speed training: intervals, hill repeats, fartlek, and tempo:
Intervals are usually done on a track but can be done on roads or trails; they consist of cycles of fast running followed by a brisk walk or jog. Some examples of intervals used in 5K training: six half-mile runs at faster than 5K race pace with three-minute recovery jogs; eight quarter-mile runs at faster than 5K pace with two-minute recovery jogs.
Hill repeats are run on short, steep hills, or longer more moderate slopes. In short hill repeats, it should take about 30 to 90 seconds to reach the top, followed by a slow jog down. Do four to eight reps. Long hill repeats should take two to five minutes to reach the top followed by a slow jog back down. Do three to five reps.
Fartlek is a steady run of three to five miles injected with quick bursts (for one to three minutes) of speed at 5K pace and faster, each followed by a recovery period of about three minutes of running at a steady pace.
Tempo is used more for longer races but will still benefit the 5K racer. A basic tempo workout: Run for 20 minutes at a steady pace about 20 to 30 seconds per mile slower than your usual pace.