The first thing to keep in mind when you’re beginning a fitness plan is that you need to be safe. Many people overdo their workouts right out of the gate, challenging their muscles with as much weight as they can bear. But what they don’t realize is their likelihood of injury is greatly increased by starting out this way.

A safer and more reliable way to begin building muscle is to start slow. Even if your main concern is how to build muscle the fastest way you can, you should take it easy at first because if you sustain an injury you’ll have to wait until you heal before working out again, and this will put you back to square one.

Therefore, you should start with exercises that target muscle groups instead of specific muscles–in other words, compound exercises. Additionally, calisthenic exercises (those that rely on your body weight instead of external forms of resistance like weights or exercise machines) are generally safer, more practical, and of course cheaper. This doesn’t mean that you should never use weights or exercise machines, because you should. You just need to prepare your body first by developing the support muscles that muscle-isolation exercises are designed to ignore.

Push-ups, for example, are a safe way to build your triceps, pectorals, abdominals, and even deltoids. And because they don’t require extra equipment, you can do them in your own home whenever you want to without buying anything to get started. Compound calisthenics will also provide you with more practical strength than isolation exercises.