Goal : Faster Pace

In order to run, bicycle, or swim at a faster pace, you must teach your muscles to move faster, tolerate the discomfort of lactic acid accumulation, and remove the lactic acid faster. You can accomplish this by (1) exercising continuously at a very fast pace or (2) doing very short intervals at a very fast pace interspersed with recovery periods in which you exercise for a short period of time at a very leisurely pace. Interval training refers to doing a fixed number of repetitions over a fixed distance at a fixed pace with a fixed recovery. (The recovery is the slowly exercised distance after each fast burst.) For example, you may run 10 quarter –miles in 100 seconds each, separated by a slow jog of an eighth of a mile between each fast run. If you want to get faster, you may want to include an interval work-out in your program at least once, but not more than three times each week.
Alternate Hard and Easy Days

You’ll improve by doing intervals once or twice a week, but be sure you don’t do them on consecutive days. Every time you exercise vigorously your muscles are injured slightly, and it takes 48 hours for them to recover. It’s a good idea to exercise lightly on the easy day, rather than resting altogether. You may even prefer to switch to another sport for the easy workout. Always listen to your body in order to avoid overuse injuries. If your body feels tight after a recent vigorous workout , you may prefer to take the day off together.
Long and Short Intervals
Long intervals are fast laps that at least two minutes each; these teach you to tolerate the discomfort that accompanies a high level of lactic acid, and also teach your body to eliminate lactic acid faster. The high levels of lactic acid in your bloodstream tire you quickly, so that even great athletes don’t do more than four or six of these long intervals in any average workout.
Short intervals are fast laps that last a maximum of 30 seconds each; these teach your brain to coordinate your muscles at a faster pace. Both long and short intervals are performed almost as fast as you can. Since very little lactic acid accumulates during each short interval, you’ll be able to accomplish a lot more short intervals than long intervals in any workout. Top athletes do as many as 100 repetitions of short intervals in a workout.
Goal: Successful Competition
If you want to compete, interval training is an excellent type of training. Many women who went to school several decades ago lacked the encouragement to become competitive. Casual, recreational exercise was the most they aimed for, even if they were born with a great amount of natural athletic ability. You may be one of these women, and this may be the right time for you to become a competitive athlete. However, no one can select this goal for you. If you have no desire to compete, you don’t need to speed work, and it’s perfectly all right to exercise slowly all the time. Never feel uncomfortable or embarrassed to exercise at your own chosen pace.
On the other hand, many women who were programmed to believe that strenuous exercise was “unfeminine”actually have a good deal of ability. What some of them lack is motivation and confidence. Such women deserve as much encouragement and support as possible to enable them to train properly to develop their skills and meet their goals.