If you blew off your workout routine for a week (or two, or three—no judgment!), getting back to your pre-hiatus fitness level can be challenging. Whether an injury, illness, vacation, or overbooked social life is to blame, having to revert to square one at the gym is a drag—but tempting as it might be, you shouldn't jump right back in to where you left off. Here, three smart tips from trainer Rob Sulaver for starting over at the gym safely.

1. Accept where you're at

Don't try to pick up where you left off just because you think you should be in better shape (a recipe for injury). "You're starting over, so you have to expect that you'll be weaker and slower," says Sulaver. "Be kind to yourself and to your body and you'll eventually get back to where you were."

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2. Revisit the basics

A good rule of thumb: Start with about 10 percent less than the weight you previously used, and rest after a couple of sets—then see how you feel and adjust accordingly. "If you were using 25-pound weights for four sets at your peak, you might try slightly over 22 pounds—or, if that's unavailable, whatever is the next lightest—for two or three sets the first week back," suggests Sulaver.

3. Map out your plan

Do so not only in your head but also on paper (or in your phone). "By scheduling your workouts and knowing exactly what you're going to do when you get to the gym, you'll be more efficient and less likely to blow it off altogether," says Sulaver. The more specific you are—weight, sets, reps, cardio, weekly goals—the better your rebound will go.