According to the American Council on Exercise, the No. 1 reason people give for not exercising is "lack of time." Not far behind is a "lack of results" once they do start exercising. Don't waste your precious time exercising, avoid these five common mistakes and you won't be wasting your time and even see remarkable results.

1. Not setting specific, attainable goals. There are so many reasons to participate in regular exercise. However, you must acquire your very own goals specific to your needs and wants if you are going to succeed in your program. Make a list of reasons you exercise and then attach specific goals to each exercise. For example, if your reason for exercise is to reduce body fat then a specific goal you can attach to that is exercising on the elliptical trainer for 30 minutes 4 times a week at 80% of your maximum heart rate. You need to review your goals often. I recommend that my clients check their schedule at the beginning of each week to make sure you allot time to exercise. Also, it is proven that if you share your goals with a friend you will be more likely to follow through. It is all about being held accountable.

2. Skipping the warm-up. In 5-10 minutes a proper warm up will increase your metabolic rate to get oxygen to the working muscles, fire up your core body temperature to enhance caloric burn, plus help prevent injury & lessen fatigue. Don't skip the warm up.

3. Lack of variety. Variety will help you achieve results, prevent boredom and reduce the likelihood of overuse injuries. Once you master a workout, you'll see diminishing fitness gains unless you mix it up. Are you fixated on one mode of cardio? If you are addicted to the elliptical machine, then it will benefit you to try different programs on the machine. There are so many ways you can vary the machine exercises from different levels of intensity to different programs like cross-training or fat-burning. Trying different cardio activities will most likely increase aerobic endurance as you challenge new muscles and give those overworked ones a well-deserved rest.

4. Switch gears. The body has two types of energy producing systems. There is the aerobic system which allows you to perform at a moderate pace mile after mile and uses oxygen to convert carbohydrates to energy. And there is the anaerobic system which fuels short bursts of activity, like sprints or jumps, by drawing on energy from carbohydrates stored in the muscles. To achieve maximum fitness gains it is important to train both systems. This type of training is commonly referred to as interval training. Interval training refers to alternating between short bursts of intense activity with active recovery.

5. Not paying attention. It is imperative that your posture is correct during each training session. Most common posture mistakes are: knees jutting beyond ankles, shoulders shrugged, pelvis untucked and loose abdominals. Always be aware of your posture! I cannot stress that enough. If you work on exercise equipment like the treadmill or elliptical be sure you do not lean on the equipment.