Do you always head for the same aerobics class or stationary bike when visiting the gym? Are you listening to the same track and zoning out? Do you feel like nothing is changing?

If nothing changes, then nothing changes. Variety not only keeps your mind engaged, it also accelerates muscle growth because muscles respond the most dramatically to new stimuli. Here's how to mix it up and see new growth with your gym workout.

Change your workout time

If you're used to working out in the morning, switch to mid-afternoon or evening. Similarly, if you're currently on a five-day schedule with two days off, try working out every other day. If you have plenty of time and are physically ready, try working out twice in the same day to supercharge your progress. Shorter workouts can be more intense, so hit it hard!

Shake up your diet

Great physiques are made in the kitchen as much as in the gym. Without incremental tweaks to your diet, you'll never see any significant progress. Add the good, and slowly trim away at poor habits.

If you're a slow muscle gainer, add some protein after your strength workout, and if you can't quite see your abdominals yet, consider cutting back on refined carbs and sweets. Keep a journal and note what is working for you.

Change your loads

Do you usually perform high-rep, low-weight reps? Go heavy on the same sets, alternating each week. Conversely, if you’re used to lifting heavy, try doing a high-rep workout instead, pushing yourself at the end of each extension and contraction to increase your range of motion.

Another way to stimulate your muscles is to alter the speed of the movement. For example, during squats you can lower your body slowly and then use a burst of speed on the extension. For the next set, do the opposite.

Use that dashboard

Experiment with different settings and programs on those cardio machines! Treadmills, ellipticals, and bikes can be turned into high intensity interval (HIIT) powerhouses. Plan a workout using three different machines (or an AMT), staggering in some intense abdominal work between each session. Focus on good posture and spine alignment to challenge your core while in motion.

Introduce new methods

Is there an intriguing piece of equipment or a power move that you've been wanting to master? Have you always wanted to learn how to perform a squat or dead-lift? Make a note of what you'd like to learn and make an appointment with a trainer. Master a new move or machine every month, and you'll definitely see the change you crave.

Master compound moves

Compound movements are the building blocks of any serious fitness program. Done properly, they build muscle, increase explosive strength, burn fat and train the entire system holistically.

Basic compound moves include squats, bench presses, dead-lifts, rows, pull-ups, chin-ups, military presses and overhead presses. By building your workouts around these power moves, you'll build a balanced and functional physique.

Even some seasoned exercisers may have to work hard to master the proper form, but it is well worth it to do so. There is equipment and training that can help you develop the strength and flexibility to perform these strength staples correctly. Don’t be afraid to approach a trainer with the goal of mastering these moves, and practice diligently -- you will succeed.

Your workout program should never quite become routine. Of course, there may be days when you want to take that class that fits like an old shoe or zone out on the elliptical machine to your favorite tunes. But, in general, you should strive to keep things as varied as possible. Don't try to introduce too much novelty all at once, but add incrementally and stay curious and engaged.

If you could master one new fitness skill, what would it be?