1) Not Paying Attention
People often say they like boot camp classes because someone tells them what to do. "I confess: I love the person who gets so into the workout that she doesn't hear me," says Alexandra Allred, lead instructor at the Main Street Gym in Midlothian, TX. "She came to work, to sweat, to put in full effort and embrace the entire training experience." But if being in the zone borders on zoning out, you could miss corrections that can protect you—or others—from injury. It's essential to stay present and aware, both of your own body and of your surroundings, rather than going on some kind of exercise-induced autopilot. That means both hearing the instructor's cues and observing your own form and being aware of your neighbors in the class. No one likes a space hog—or being smacked or kicked by a flailing limb.
2) Rushing Through the Moves
News flash: A 45-minute class or a 60-second interval won't go any faster because you're moving on hyperdrive. "The goal with timed workouts is to do every rep properly first and foremost—not to get in X amount of reps," says Derek Durkin, instructor at Barry's Bootcamp in Boston "Using poor form to race through will often lead to injury, and even chronic injuries."
3) Not Taking Advantage of Modifications
There's a learning curve in terms of training your body to move a certain way. Even regular boot campers can benefit from sometimes taking it down a notch, in favor of perfecting the range of motion or improving a particular skill. If the instructor doesn't offer a way to scale it back, ask for one. And get into the habit of mentioning to an unfamiliar instructor before class begins if you have any physical limitations (a bad knee, a trick shoulder), so he or she can work with you to keep the moves safe and effective for you.
4) Playing it Too Safe
On the other hand, if you've been doing the same versions of the same moves with the same weights for months, it's time to challenge yourself. Good instructors will notice if you're ready for the next step, but if you're feeling up for it, grab an extra set of heavier weights (ahem, you won't get bulky), or attempt those on-your-toes pushups—worst case, you can slip back into your comfort zone for the last set.
5) Not Eating Right
Boot camp is demanding. Yes, that should be a no-brainer statement. But Allred can easily spot those who aren't eating right. "They slow down, can't keep up, can't lift as much or jump as high—and they end up burning fewer calories," she says. "They can't go as long as they could've if they would only eat properly." On the flip side, returning all those calories you burned back to your bod in the form of a large post-workout protein shake also defeats the purpose.
6) Skipping the Stretch
We know you're busy. You raced out mid-conversation with your boss to make it on time to class, and you have a date for skinny margs with your girlfriends right after. But not only is it bad form to blast out of class before it's over, it's bad for your form literally. Boot camp, like any high-intensity interval class, pushes up your heart rate and taxes every muscle. Your body worked hard for the preceding 40 minutes, now reward it with some much-needed recovery. That tequila happy hour can take five.