There I am, out on my five-mile run in Central Park, headed up one of the many steep inclines scattered along the scenic Park Drive. Suddenly, I feel a throbbing pain in the middle of my right shin. "Oh, no," I think, "not again."

As things turned out I dodged a bullet, but other times I've not been so fortunate. Some questions arise. Why did this injury happen? I wasn't doing anything wrong, so why did I get hurt? What can I do to prevent a recurrence?

The answers to these questions are interrelated. Stuff happens when you exercise. It's as simple as that. I'm a good exerciser. I've been running since the late 1980s and lifting weights since the early 1980s. I've even written a book on fitness and wellness. But I still have injuries. What's going on?

We need a plan for exercise. My strategy, with myself and my patients, is to train hard and train smart. Training hard means maximizing your effort while avoiding overtraining. You train within yourself, doing what you're capable of doing and then slightly more. It's the slightly-more part that results in the strength gains, the endurance gains, and the speed gains.

Training smart means paying attention to what's happening in your body as you train. "Paying attention" is a learned skill. It requires focus and repetition. Visualization is an important part of focus. If you're weight-lifting, visualize the prime mover for that exercise, the muscle for which the exercise is designed. The prime movers for lat pulldowns are, of course, the latissimus dorsi, the broad back muscles that creates the "V" shape. The prime mover for the bench press is the pectoralis group. The prime mover for military presses is the deltoid.

When you're running, visualize a straight, yet fluid spine and strong abdominal muscles. Your head is erect and your chest is open. Visualize a long stride, a soft landing, and a strong pushoff, with your leg kicking straight behind you. Your arms are active yet relaxed, and your shoulders sit comfortably on your rib cage.

Training smart means trusting your instincts, rather than listening to your ego. This is a tough one. At the time, it seems so important to do that last rep. "One more rep, I can do it." Your prime movers are exhausted, so your postural muscles engage, doing the bulk of the work to move the weight, and you injure your neck or lower back. Now you have to avoid lifting for seven to ten days. Was it worth it? Of course not, but I can say from personal experience that this battle between common sense and ego ("looking good") takes place over and over again.

Now, you can do that last rep if you maintain your form. This is another element of the train hard/train smart protocol. Form is everything. If you have to sacrifice form in order to do those last few reps, you may get an unexpected, unwelcome result. Likewise in running. During training, when your form breaks down, that's a signal to slow down and recover your form. If your training is done with attention to good form and good mechanics, you will be more likely, when the time comes, to run a good race at a good pace.

As in much of life, there's a fine line between training hard and overtraining. With greater self-awareness, it becomes more likely that we'll achieve the results we're looking for. Remember, the benefit of training is for the long term.

Dr. David Lemberg, the author of Commitment to Fitness: Real Fitness for Real People, is a board-certified chiropractic orthopedist in his twentieth year of private practice on Manhattan's Upper East Side. He has been published in national trade magazines such as Muscle & Fitness and Dancemagazine, the peer-reviewed Topics in Clinical Chiropractic, the Florida Chiropractic Society Review, and The Chiropractic Journal. Dr. Lemberg is a member of the postgraduate faculty of Los Angeles College of Chiropractic, and for the last ten years has taught orthopedics to chiropractors in venues across the United States and in Canada. He was Clinical Editor of the quarterly journal, Spinal Manipulation, published by the Foundation for Chiropractic Education and Research, from 1990 through 1995.

Commitment to Fitness: Real Fitness for Real People may be ordered through Dr. Lemberg's web site. His office is accepting new patients: 212-535-7429.