Compound or isolation exercises: which is better? The truth is that neither one is "better;" each are different tools in your workout arsenal, suited to different tasks. However, isolation exercises are often used too early and too often-especially by beginners.

A compound exercise requires two or more different joints to move. For example, when you do a squat, your ankles, knees, and hip joints bend-if you're doing it right. With an isolation exercise, only one joint moves at a time-as with bicep curls, for example. Even if you do the exercise with both arms, you're still only bending the same type of joint-so it's still an isolation movement.

Are you getting as much from your workouts as you could be? Here are a few facts about compound and isolation exercises that will help you determine where and when it's appropriate to use each one.

Compound exercises build muscle more efficiently. In nature, we never really use just one muscle. We use many when we're performing strenuous tasks. Think about how many joints bend when you're moving boxes into your new house, for example. Then think about how many times you've performed a movement equivalent to a calf isolation exercise in life-it's pretty likely you'll say "never."

Because it's natural for our bodies to use multiple muscles at the same time, our bodies have evolved to make the most out of every exercise that uses multiple joints. Compound exercises involve more motor units (those are motor neurons and their surrounding muscle fibers) than isolation exercises do. The more of these you involve in an exercise, the more you encourage muscle growth and strength increases. The more motor units you use in each exercise, the more you're encouraging your body to grow and become stronger. An isolation exercise just doesn't give you as much bang for your buck.

Isolation exercises target specific muscle groups. An isolation exercise, on the other hand, focuses on a single muscle group. Bicep and tricep curls, flyes, lateral raises-these are all isolation exercises. Many machines are for isolation exercises, although you can still do them with free weights and a few machines allow for compound exercises.

Some body builders aren't as strong as they could be. It's an urban legend that body builders aren't as strong as they look. There's a grain of truth to that, however. Body builders generally work out to win physique contests, not lift heavy weights. Because of this, they often rely on isolation exercises to sculpt their muscles-and if they do it too soon, they won't give their bodies time to develop their maximum strength potential, even if they look ripped.

Isolation exercises should be used after you've been working out for a while. If you want to prevent yourself from being weak on practical strength-no matter how ripped your physique-don't start isolation exercises too soon. These exercises should come into play after you've been working out for a while and can tell which parts of your body are lagging behind. For example, if you've been working out for half a year on a routine based on compound exercises, you'll probably find that a part of your body-say, your calves-is still a little small. That's because in the compound lift, other muscles are doing most of the work. Then you can use isolation exercises to target those spots. But you won't be able to choose the right exercises until you've had time to build strength and notice where you need the extra attention.

Most professional athletes rely on compound exercises. For example, NFL football players. They need strength, and chances are they hardly ever use isolation exercises-it doesn't matter how they look; it just matters how they perform. A player who works out using mostly isolation exercises will be less strong than one who uses mostly compound exercises-and on the football field, you risk injury if you're significantly weaker than your opponents. Still, a lot of football players have great physiques-and the strength to back it up.

When you rely on compound exercises, you can get in and out of the gym more quickly. You get more results out of compound exercises, so you have to do fewer reps at the gym. As a matter of fact, multiple sets of compound exercises are often not a good idea-especially when you're just starting out. These exercises are much more intense than isolation exercises, and overdoing it can cause overtraining and risk of injury. As long as you're exercising your body to the point where it physically cannot perform another rep-at least for a second-you're making gains.

Isolation exercises force weaker muscles to perform. One problem with compound exercises is that because they recruit several different muscle groups, some groups tend to do more work than others. For example, let's say you've been using a bench press to work out your chest and arms. Your triceps are still weak after several months of working out. That's because your chest muscles are stronger at this point, and they're doing most of the work. You can use an isolation exercise to force the triceps to work on their own, building strength in this area.

Isolation exercises should be used to "sculpt" the body after you've built a solid base. Open up a body building magazine, and chances are you'll see famous body builders' workouts-mostly featuring isolation exercises. Pro bodybuilders do a lot of isolation exercises to increase definition. Beginners seldom get good results from them-it's why so many aspiring body builders get discouraged.

Isolation and compound exercises are both good for different things. The problem comes when you use isolation exercises too soon, or when you rely entirely on compound exercises and allow smaller muscle groups to stay weak. Use both and in the right order, and you'll be able to get the most from your workout routine.

About the author

Jean Lam is the webmaster of Body Building Resource which provides articles on weight training, nutrition and fitness, body building book and DVDs.