By Vaughn Gray

Building muscle mass isn’t just for guys looking to up their bench press and grow their biceps. Building muscle is a great way to raise your metabolism, helping you shed unwanted fat and keep it off. And for most athletes, a degree of bulk, and the strength and power that comes with it, can pay huge dividends in terms of performance. Packing on a few extra pounds of muscle can also help fill out your physique. The keys to building muscle are the same as the keys to other exercise goals: First be sure to train smart. Then worry about training hard. Let these simple principles guide the way:

Muscle Building Principles

1. Never Sacrifice Form

It’s tempting to try to squeeze in a few extra reps by compromising form, but, in the long run, it does more harm than good. Poor form taxes joints, and, in many cases, joint strength becomes the limiting factor on muscle growth as your body won’t let you work and develop your muscles beyond what your ligaments and tendons can withstand (ever notice how week a limb with an injured joint feels?). In addition, you should only be training to absolute failure once every month or so (see the action steps below). Forcing extra reps with bad form week after week will overtax your muscles as well. Finally, good form contributes to better muscle balance, and a balanced body is more aesthetic and more functional than an imbalanced body. Our Weight Lifting Form Tutorial will show you proper form for a variety of exercises for every major muscle group.

2. First Integrate, Then Isolate

To maximize muscular gains, you want to perform a combination of compound lifts and isolation lifts. Perform compound lifts first, and follow with isolation lifts. Compound lifts use multiple muscle groups, like a bench press, which uses the chest, shoulders, and tricpes. Isolation lifts, conversely, use only one muscle group, like a chest fly, which mostly isolates the pecs.  In compound lifts, you can generally move more weight than you can in isolation lifts, which increases the total mechanical stress on your muscles. The high levels of mechanical stress created by compound lifting send powerful signals to your cells, which up the levels of anabolic muscle building hormones, leading to larger, stronger muscles.

When designing the compound lifting portion of your workout, choose "functional" exercises like squats, dumbbell chest presses, and standing overhead presses (see our Weight Lifting Form Tutorial for descriptions of these exercises). A functional exercise is an exercise motion that the body is designed to perform. A lot of the exercises in any given gym, like leg presses, leg extensions, hamstring curls, and abdominal crunch machines, are non-functional exercises and should generally be avoided. Take a look at our Improving Posture and Alignment Tutorial  to learn more about functional exercise.

Follow your compound lifts like chest presses and overhead shoulder presses with isolations motion like chest flys and side laterals. Isolation motions place targeted stress on one muscle group, allwoing you to fatigue that specific muscle group more effectively. The more thorough, targeted muscle fatigue acheived in isolation lifts works synergisticly with the greater overall mechanical stress created by compound lifts to maximize muscular growth. 

By way of example, an ideal chest and triceps workout would start off with 2 or 3 compound motions like dumbbell chest presses, incline bench presses, and cable crosses, and finish with isolation motions like dumbbell flys for your pecs and nosebreakers for your triceps. An ideal back and biceps workout would start with compound motions like pull ups and cable rows, and finish with lsolation motions like bent rows (which largely isolate the back musculature and place less stress on the bicpes) and biceps curls.

Generally speaking, you should avoid working your legs in isolation unless you are a pure body builder. Isolating your hamstrings or quads may contribute a bit to development, but these muscles are meant to be used as a group, and isolating your leg muscles with machines can impair their coordinated function and predispose you to injury. This is more true of the quads, hamstrings, and glutes, and less true of teh calves, which handle isolation better. If you are a bodybuilder looking purely to develop greater muscle mass and tone, just be sure to limit the amount of machine-based isolation exercises you do, and concentrate mostly on functional exercises involving free weights and cables.