Incorporating some carefully designed faster-paced runs is essential to a program seeking faster performance in your daily training runs and in races you enter. However, the key point to remember is that speed work is an advanced training technique for an experienced runner and not for a true beginner.

For the more accomplished runner, though, incorporating some advanced running techniques is necessary to improve your time from one race to the next. Your best race times are referred to as PRs (personal records) or PBs (personal bests).

In short, don't entertain the notion of adding speed work to your training regimen until you have been running regularly (logging 20–25 miles per week) for a minimum of a year. Doing so without this solid mileage base greatly increases your chance of incurring an injury. If you do decide to focus on this aspect of your running, it is important to read this entire section before beginning any speed workout on your own.

The Risks

Despite the benefit of increasing your speed, incorporating advanced training techniques exponentially increases your risk of injury. You really need to think about whether you are willing, after months of training, to risk injury that prevents you from participating in your chosen event.

Even runners who feel ready to work on improving their speed need to be careful. Speed workouts are sessions in which you need to push yourself. But pushing too hard may result in injury. You have to be smart. Exert yourself — for there is no gain without some physical discomfort — but don't be macho. A mistake here can result in serious, if not languorous, injuries that can keep you from running for weeks or even months at a time.

The Benefits

There are many benefits to adding advanced running techniques to your training beyond merely improving your speed and chocking up faster race times. The physical gains attained through speed work are more numerous than you might think. There's the obvious, which of course is improved strength and speed.

However, these are actually byproducts of the training. With higher intensity training, you now have a better oxygen delivery system. You can run faster and still stay at a comfortable, aerobic (meaning, using air) pace. Your body becomes more efficient at delivering oxygen to your muscles, and your muscles function better while using less oxygen.

When your body exceeds its capacity to use oxygen as fuel, you begin using glycogen as your primary fuel source. A byproduct of this anaerobic (without oxygen) method of energy production is lactic acid.

Rather than your body going into oxygen debt (characterized by that heavy, burning feeling in your legs), in which your muscles tie up due to a buildup of lactic acid from a lack of oxygen, your anaerobic system can be trained as was your cardiovascular system. With specific anaerobic training, you can exceed limits that previously held you back.