Are you working out faithfully three times or more a week but getting no results? There are a variety of things you can do to get out of your rut. First of all, give yourself some applause for sticking with it; it is no easy task. Secondly, you may need to re-evaluate your goals; chances are you are not going to look like a supermodel, so ease up on yourself. You can be sure you are getting health benefits and more energy, even if the scale seems stuck.
The best way to get out of a rut is to change things up. I cannot tell you how many people I see at the gym who do the exact same workout every day. Not only is this mind numbing, but your body adjusts to routine and stops improving. Try a treadmill instead of a bike, take a sculpting class instead of Pilates, hire a personal trainer or rent a fitness DVD. Take it outside; even in the winter an outdoor workout can make the mundane new. Download some new music: Google “workout music” and you can find a variety of sites where you can stream or download tunes guaranteed to rev up any workout. If you absolute refuse to change your basics there are still things you can do to reinvigorate your muscles (and your brain):
Do your workouts in reverse: You still need to warm-up first and stretch after, but if you reverse the order of your exercises you will be surprised at how different it feels.
Change the tempo: One day do each exercise very slowly. This is amazingly difficult as it takes momentum out of the picture and forces your muscles to do more work.
Do one and a quarters: Lift the weight for a full range of motion, release it a quarter, then complete the exercise: (For a bicep curl bring the weight to your shoulder, lower the weight a quarter of the way, bring it back to your shoulder, then lower it back all the way). This is another way to increase intensity without changing the exercise.
Train in pyramids: Do one set with very light weights for 16-20 reps, increase the weight and do another set of 8-12 reps, increase the weight again, then do 6-8 weights. Next workout go from heavy to light for reverse pyramids.
Try to find something you enjoy; it is hard to get stale if it is something fun. Change it up and do so often; you will rev up your routine and get better results.