You know you can't just waltz into the gym and do whatever looks hard. You need a solid goal, and then you need a plan on how to get there—safely. Without those two things, you'll end up looking exactly the same as (if not worse than) you do right now. Worse, you could get injured, which would mean a lot of pain, inconvenience, and time out of the gym. We called in L.A. coach Jason Feruggia to get the four most important rules for safe muscle gains, so you can get the most out of your plan.

Balance

You won’t make any progress if you’re hurt. A program that doesn’t include at least as many sets of pulling exercises as it does pushing will set you up for a shoulder injury. You also need time for recovery, so make sure your workouts are spaced appropriately and don’t lift heavy more than three times a week. “If you’re over 35, it’s never necessary to go heavy,” Ferruggia says.

Challenge

There’s a reason squats and bench presses are used frequently in studies that measure muscle and strength—they work. Base your program around hard exercises that work the most muscles, such as squats, presses, rows, chinups, deadlifts, and all their variations.

Specificity

If your goal is to boost your bench press, you need to train on the bench frequently and target your weak points. Doing a high-rep circuit routine won’t help you bench more. Focus on one goal at a time.

Variety

“Switch up variables in your workouts every one to four weeks,” Ferruggia says. “The more advanced you are, the more frequently you should change things.”