2. Warm Up and Cool Down
The chances of having an injury are greater when their muscles are cold. There is a simple physiological reason for this: When you first get up in the morning, your muscles and soft tissues are tight. In fact, your muscles are generally about 10 percent shorter then than their normal resting length.

As you start moving around, your muscles stretch to their normal resting length. When you start to exercise the muscles, they stretch to about 10 percent more than normal resting length. This means that from the time you get out of bed until the muscle is warmed up the muscle stretches as much as 20 percent.

A longer muscle is much less likely to become injured than a short, tight muscle. Further, muscles are designed to move bones on either side of a joint. Through basic laws of physics, a muscle is more efficient and much less likely to become injured when it is longer, since it can exert more force with less effort.

Likewise, it is disastrous to finish a training run and just stop. Many runners try to get the most out of their runs by sprinting the last couple hundred yards or so. Then they stand and try to catch their breath. This is asking for injury. It is also the time when susceptible individuals are most at risk of having a heart attack. Almost all exercise-related heart attacks occur just after runners stop running, not while they're actually running. This is because when you exercise, your body relies on your muscles to help pump or push the blood from your legs to your heart and brain. When you stop running, that muscle action stops and your heart and brain suddenly get less blood and oxygen. (This is an excellent reason for a cooldown period of slow jogging or walking.)

The cooldown helps keep the blood flowing to the muscles and allows your body to work its way down from a state of high exertion to the eventual resting condition. Keep walking for a few minutes, at the very least, after every run until you have cooled down.


3. Stretch Firmly but Gently
The best time to stretch your muscles is not before you exercise but after a run when your muscles are already warmed-up and elongated. Flexibility exercises always stretch the muscles slowly and gradually.

Stretching movements should never be jerky, stiff or hard. The proper way to stretch is to stretch the muscle gradually for 30 seconds at a time to allow it to lengthen. Do this three or four times per area, daily.

If you stretch or pull hard on a muscle, it sets up a reflex where the muscle pulls back, shortening and tightening. This is not what you want. It will give you a stronger muscle, but not a looser, longer, more forgiving muscle.

4. Keep Your Training Schedule Flexible
The easiest way to avoid injuries is never to train hard on a day when you feel any pain when you roll out of bed. As easy and simple as this advice sounds, you'd be amazed how many people ignore it.

Let's say that you are training for a certain race and your training schedule calls for a 10 percent increase in mileage this week. Yet you're feeling a little twinge in your hamstring.

Do you go ahead and follow the schedule? Or do you alter it based on listening to your body?

You know the right answer. Yet many runners insist on adhering to the printed training schedule as if it were gospel. They refuse to deviate by a single mile from that written program, believing any modification of it would ruin their chances of running a good race. In fact, the reverse is true. They're far more likely to miss the race by slavishly following a predetermined schedule than by adapting it to current needs.

All good training schedules assume that you aren't experiencing any unusual pains before, during or after the run. If any of these pains occur, don't hesitate to modify the scheduled workouts.


5. Alternate "Hard" and "Easy" Training
If you try to improve to your maximum potential, some pains are inevitable. These can occur several hours after a hard workout or race--or one or two days later.

All this really means is that you need some recovery time. Then you will be off and running again.

This is why most experts recommend never performing hard workouts two days in a row. Give yourself at least one day of easy running or rest between hard workouts. This is known as the "hard-easy" method of training. If you run fast one day, train slowly the next. If you run long one day, go short the following day.

Never run long two days in a row or fast two days in a row, and don't run long one day and fast the next. You'll simply cancel out the gains of the long or fast workout, because your body is desperately trying to recover. You're stressing weakened tissues that the body is trying to repair.


6. Pace and Space Your Races
You can and must push your limits sometimes in order to progress. But you can't do this too often or by too much.

In other words, you must pace yourself. This is true both for individual runs and over periods of weeks, months and years.

The most important time to pay attention to proper pacing is while racing. At races, you can easily get caught up in the emotion of the crowd and be drawn into starting too fast.

Pacing also has longer-term applications. Racing is very hard and potentially damaging work and you put your future at risk if you race too often. So you must "pace" your races in terms of frequency. Give yourself plenty of time to recover after any race.

The general rule: Take one easy day or rest day for each mile of the race. And certainly don't race again until that period has passed. For example, allow an entire easy week following a 10-K race and an easy month after completing a marathon. Top marathoners believe they can only run two or three good marathons a year; this grueling event takes that great a toll.