The only way to add shape and tone to a muscle is to exercise it – stress it out – stimulate it. If you don’t use it you will lose it theory! We all know that squats, lunges and leg presses will give us that shape and tone we want for our backside. But wouldn’t it be great to get those same benefits when you do your aerobic workout? Especially when we know so many of our clients, both male and female are looking to add shape and tone to their rear-ends.

Treadmills, stair steppers, elliptical machines and stationary bikes are great for aerobic conditioning and are highly recommended. But those machines don’t activate or stimulate our hamstrings and gluts enough to add shape and tone to our butt muscles. Almost everyone wants a nice, shapely, toned bottom and strength training will definitely address that when properly performed. But did you know that all your hours on those indoor aerobic machines add nothing to your gluts.

When you walk, jog or climb stairs you stimulate all the muscles of the lower body. The continual contraction of the quadriceps, hamstrings and gluteus is what moves us down the road or track. The various exercise machines that are designed to simulate running, climbing and biking are great for the aerobic part of the workout. Unfortunately, due to the design of the machine - the equipment ends up doing all the work we want our hamstrings and gluteus to do. This is why they are not great for adding tone and shape to our bottoms.  Don't get me wrong, I think they are great for aerobic conditioning, but don't expect to tone up your butt muscles with them!

Let’s first look at the basic walking or jogging movement to better understand why those machines don’t help tighten up our gluts. When you step forward with your lead leg, it is the hip flexor and quadricp muscle that contracts and extends your leg forward. As your front foot hits the ground…what pulls you forward is the contraction of your hamstrings and glut muscles. The continual contraction of all the muscles around the thigh makes walking a complete workout for the lower body.

As we compare the same movement with the treadmill you will see that the contraction of the quadriceps to extent the leg forward are the same. The problem or weakness of this exercise on a treadmill - for toning is the simple fact that as your foot hits the ground, instead of having to contract the hamstrings and gluts to propel the body forward. The machine will automatically throw your lead leg – back! Because of the mechanical action of the machine, the hamstrings and gluts don’t get stimulated. And if you don’t use it or stress it – you don’t tone it!

The shortcomings for the treadmill and all other aerobic machines are a result of the very nature of the apparatus. When you look at a stair stepper you will see that instead of having to contract your hams and gluts to propel your body up the stairs….it is the weight of your "lead" leg that causes the foot pedal to descend. Even though it feels like you are going up a flight of stairs – it’s not the same thing. Like the treadmill you are not stimulating the gluts anywhere close to the level that they need to be in order to stress them. It’s like doing the proverbial "12 ounce" curls…..we can do those all day and they won’t add any shape to our biceps.

As far as the elliptical machine and stationary bike – they have the same inherent problems. Step forward on the elliptical machine or press down on your bike pedal and without having to contract the hams and gluts the other leg is ready to activate the quadriceps again. Again you are basically omitting the need of the hamstrings and gluts muscles to perform these exercises. I know some cyclists that do activate their hamstrings when they pedal, by pulling the pedal around. But it is only the well trained, elite cyclist who rides with "clips" that gets that benefit. They are still not activating or stressing their gluteus muscles.

Look at the physique of a runner, sprinter and that of a cyclist. You will see that those runners who actually train on "mother earth" have well developed quads, hams and gluteus. Cyclists on the other hand have much larger quadriceps in proportion to their hamstrings, because the primary stroking motion is done with the quads.

Don’t get me wrong. I am a big fan of these machines for training, but I always try to encourage my patients/clients to get their aerobic training on ‘mother earth." When you do that you can kill two birds with one stone…..the aerobic benefits along with the toning benefits of our gluteus maximus.  If you want to add shape and tone to your back side, try interval running, sprint work or doing some real stairs.

Dr. Len Lopez is a nutrition and fitness expert and author of To Burn or Not to Burn – Fat is the Question, and "5 STEPS Closer." He is the host of Action Steps for Health and a frequent guest on radio and television. His approach to health and fitness is based on TEE-Time Philosophy of getting the most for your Time, Energy and Effort. Use the online health quizzes and check to see if you are staying in your fat-burning zone at DrLenLopez.com or call 972.458.0099