Brad Schoenfeld specializes in women's fitness and has authored several books on the topic. In his latest book, Women's Home Workout Bible (Human Kinetics, 2010), Schoenfeld details the Ten Commandments of Fitness, portions of which are shared in this adapted excerpt.

Treat these commandments as if they were inscribed in stone by the fitness gods. They should form the basis of every exercise routine, whether you are training to become an Olympic athlete or are simply looking to tone up and get healthy. Read them over. Follow them to the letter. They'll go a long way toward helping you get the most from all that hard work in your gym.

1. Train According to Your Goals. You shouldn't set foot in your gym without first understanding the principle of specificity. This central tenet of exercise states that in order to achieve a fitness goal, you must make your training specific to that goal. The movements you choose, the energy systems you use, and the intensity of your training should closely parallel what you're trying to accomplish. For example, a 20-something aspiring fitness competitor should train in a manner that optimizes body composition. A postmenopausal woman looking to improve bone density should focus on strength moves that load the skeletal system.
2. Fuel Your Body Before Exercise. Pretraining nutrition is essential for getting the most out of your efforts. Specifically, if you do not begin a workout with an adequate supply of energy for your muscles and brain, you simply cannot perform at your best. Carbohydrate is the primary fuel for high-intensity training. During high-intensity exercise, your body uses energy at a very fast rate, and it can't supply enough oxygen to process fat as a fuel source. It relies instead on glycogen, or stored carbohydrate, which doesn't require oxygen to be broken down for energy. Include protein in your preworkout meal as well. Although it doesn't contribute much in the way of energy, protein has both anabolic and anticatabolic effects on the body. Consuming protein prior to exercise provides your muscles with a steady stream of amino acids, which maximize performance and attenuate the breakdown of muscle tissue. This practice also primes the body for muscle development by significantly increasing the synthesis of muscle protein during the first hour after exercise.
3. Warm Up Before Intense Training. Begin each session with a general warm-up of 5 to 10 minutes of light cardiorespiratory activity. You can use virtually any mode of cardiorespiratory activity, but it's best to opt for one that's specific to the muscles being trained. Jumping jacks are usually a good choice because they involve the entire body. Ditto for elliptical trainers that include upper body action. Work up a slight sweat, and then move on to your routine.
4. Continually Challenge Your Muscles. No two ways about it, the primary reason women fail in their quest to get fit is inadequate intensity of training. Many women simply don't train hard enough to improve their fitness level. They'll use absurdly light weights that don't come close to taxing their muscles (I've actually seen women talking on cell phones and reading magazines while performing arm curls and leg extensions!) and expect to achieve great results. No dice. Such a lackadaisical approach is destined for failure.
5. Train With Proper Form. Perfect form involves performing an exercise so that only the target muscles are used to complete the maneuver. The weight is lifted in the most efficient manner possible, allowing muscles to contract in a direct line with their fibers. There are no extraneous body movements and no hesitations--just one continuous motion as each rep flows smoothly into the next. Unfortunately, people naturally try to take the path of least resistance, lifting weights in the easiest possible fashion rather than in a way conducive to muscular development. Be proactive when working on form and take rep speed, breathing and range of motion into account.
6. Rest After Intense Training. Our bodies need rest, especially after a grueling workout. Exercise doesn't build your muscles, it breaks them down. The stress of intense training causes small tears in the structural components of your muscles. Your body synthesizes protein to repair the damaged muscle tissue while you're resting, setting the stage for muscle development. Shortchange recuperation and your body never has the opportunity to adequately recover from the extreme demands of training.
7. Regiment a Training Schedule. One of the best ways to adhere to your fitness practice is to make exercise a habit. Think of it like brushing your teeth-a necessity, not an option. You should have preset training days. Write them into your schedule, just as you would with an important business meeting or a family function. Unless you have a major crisis, stick to your schedule rigidly.
8. Vary Your Routine. The key to sustaining progress is to constantly change workout variables. This keeps your body off guard, never giving it the opportunity to get accustomed to a particular muscular stress. When your muscles are continually forced to adjust, your results progress at a steady rate.
9. Develop a Mind-to-Muscle Connection. Simply stated, a mind-to-muscle connection is the melding of mind and muscle so that they become one. Visualize the muscle you are training and feel that muscle contract throughout each repetition. Rather than thinking about where you feel a muscle working, you must picture where you are supposed to feel the stimulus. A mind-to-muscle connection is beneficial on two levels. First, it ensures that your target muscles perform the majority of work during an exercise. Without this connection, your supporting muscles and connective tissue tend to dominate the lift, which diminishes results. Second, when you've mentally locked into a movement, your form tends to automatically fall into place. This both improves exercise performance and reduces the possibility of injury.
10. Know the Major Muscle Groups. Like it or not, you need to know the composition of your muscles in order to get the most from your training efforts. This knowledge helps you visualize each muscle during training, fostering a better mind-to-muscle connection. It also makes you aware of the path that weight must travel to target specific muscles, improving your ability to train with proper form. Finally, it allows you to hone in on muscular imbalances, assessing which muscles need improvement and which don't.

Schoenfeld offers detail on all of these commandments in Women's Home Workout Bible. For more information, visit www.HumanKinetics.com.