Time is a runner's worst enemy. The clock is always ticking.

In racing, a runner's world centers on time. After all, getting to the finish line as fast as possible is what racing is all about.

When it comes to training, time impacts runners on two fronts. First, as covered in the July issue of RTN, it takes a lot time to experience the benefits of training - up to three weeks before a long run is absorbed fully by the body.

While it takes what seems like forever for the body to reap the rewards of a grueling interval or long-run workout, it takes no time at all for the body to begin to lose fitness.

According to Jon Warren, a coach of the popular Houston-based training program The Kenyan Way, it takes only five days to begin to lose fitness.

If an injury or busy schedule forces you to the sidelines for a week or so, say "goodbye" to lot of hard work.

You won't lose all the fitness you've established, but you'll notice a significant difference in your conditioning the next time you strap on the running shoes.

Looking for more beginner tips? Check out the "Beginners Beat" column each month in Runner Triathlete News! Click on the magazine icon above to subscribe today.