By Corrie Pikul

Starting to feel like your workouts aren't working? Here's what you might be doing wrong.

Loading Slideshow...
  • You're De-Stressing Between Sets

    Chilling out between weight sets is one of the most common mistakes Bob spots at his boot camps and the gym. To increase strength, you need to do your second and third sets of 8 to 10 reps with slightly fatigued muscles. If you have enough time to vent to your workout partner, then your muscles have enough time to recover. Instead of taking a break, Bob suggests, take a brief "pause" that lasts for just 15 to 30 seconds. "Any more than that and you'll lose the benefit you gained from the previous set," he says.

  • You've Devoted Yourself Exclusively To Bikram Yoga

    Since ditching the gym for the yoga studio, you may have improved your flexibility, but Bob says your cardio has probably slipped, and your overall fitness level may not be as high as you think. Bikram can't provide the perfect workout -- and neither can running, cycling, swimming or any other activity you do exclusively. In his book <a href="http://www.amazon.com/20-Years-Younger-Look-Feel/dp/0316133787/ref=sr_1_1?ie=UTF8&qid=1329426387&sr=8-1"><em>20 Years Younger</em></a>, Bob found that the people in the absolute best shape were those who switched between three to five different exercises each week. That's the best way to work as many muscles as possible and avoid injuries from overuse, he says.

  • You're Obsessing Over Your Biceps

    Bob often sees people lingering over super-slow biceps curls and then complaining that they don't have time to work other parts of their arms. "Biceps are one of the least functional muscles for real life," he says, pointing out that we rely more on our triceps for putting boxes on shelves, pushing up out of an office chair or reaching into the back seat of a car. He recommends mixing popular biceps exercises with moves that work the <a href="http://www.oprah.com/health/Triceps-Extension-Triceps-Exercise-Video">triceps</a>, <a href="http://www.oprah.com/health/Shoulder-Press-Strength-Training-Exercise-Video">shoulders</a> and <a href="http://www.oprah.com/health/The-10-Best-New-Exercises-for-Women/10">back</a>.

  • You're Not Obsessing Over Your Abs

    Although everyone covets a six-pack, Bob says that the core tends to be the most underexercised part of the body. After 30 minutes of cardio, 20 of weights and 10 more of stretching, who has the time? But Bob says the abdominal muscles stabilize the body and protect the back, and they're key to preventing injuries and taking a workout to the next level. Experts estimate that as many as 80 percent of us will experience back problems at some time in our lives, so it's worth <a href="http://www.oprah.com/health/Essential-Exercises-Push-Ups-Downward-Dog-Squats-Planks/3">making time for planks</a> and other core exercises.

  • You Think That Taking The Stairs Replaces The StairMaster

    Bob is always fielding questions about getting fit on the go or maximizing calorie burn during the workday. While he strongly recommends squeezing in activity whenever and wherever we can, it's important to remember that small changes like standing while talking on the phone are meant to help compensate for our increasingly sedentary lifestyles. Walking up one flight of stairs can't replace 30 challenging minutes at the gym. Bob says that to lose weight and get in great shape, you need to squeeze in at least five vigorous workouts a week.

  • You're As Addicted To Your New Fitness App As You Are (Or Were) To Angry Birds

    Tracking your workouts can be highly motivating, but with advanced apps that let you monitor every step, bite and sip and then compare your progress with your friends', this can turn into an addiction where the goal is to get the best score, not necessarily the best workout. Bob suggests taking a look at your fitness goals (to lose weight? to finish a race? to develop more muscle?) and making sure that your app is actually the best tool for achieving them.

  • You're Counting Bars And Sports Drinks As "Energy" Instead Of Food

    You may not realize that the high-carb energy bar you stashed in your gym duffel has 250 calories. Bob says it can take as much time and effort to work off one of these sports snacks as a candy bar. Adjust your total calorie consumption and your workout time -- or eat half the bar.

  • 15 Minutes Into Your Workout, You Still Feel Fantastic

    One of the best ways to break out of a plateau is to increase the intensity of your workouts, says Bob, but this may not be easy. To find out if you're working hard enough,<a href="http://www.thebestlife.com/healthy-diet-articles-and-more/nonmember_article_articles.php?st=&id=264&pg"> imagine a scale</a> from 0 to 10, with 0 being how you feel at rest, and 10 being an all-out sprint to the finish line. Aim for a 7 or 8, where you're breathing heavily and not able to comfortably carry on a conversation. So if you feel as though you could keep going forever, it's time to crank it up.

  • Your Favorite Machine May Be A Slacker

    Not all machines are created equal. For example, Bob says, you get the most challenging elliptical workout from machines that force you to lift your knees as if you were running (instead of letting you slide your feet back and forth) and that have arm handles with at least the same amount of resistance as the pedals. Other machines that take your workout to the next level: stair climbers with real steps, spin bikes that are sturdy and offer a smooth ride as well as a wide range of resistance settings, and stationary bikes with moving arm handles and wind resistance.

As a reminder, always consult your doctor for medical advice and treatment before starting any program.