Those who are tired of their skinny legs will try anything that comes to mind to build up some mass.

Holding onto a treadmill allows one to “walk” at a high incline and fast speed for sustained periods.

Walking on a 15 percent and especially higher incline, and at speeds around 4 mph – while holding on — can create the illusion of lots of heavy leg work.

A sustained pace at 15 percent incline and 4 mph is very difficult without holding on.

People with scrawny legs may get it in their head that walking, even while holding on, will build up the legs because the incline is high and the speed is brisk.

Do Not Be Deceived

If you’re holding onto something for support while moving your legs, ask yourself if it’s even remotely possible that you’re working hard enough to build mass. The answer is NO.

Furthermore, any kind of steady, sustained aerobic activity, even if you’re not cheating (holding on), taps into only the slow-twitch muscle fibers.

These fibers are designed for endurance. Hard work doesn’t necessarily translate to building leg mass.

Otherwise, marathon runners – whose training is extended and very taxing on the body — would have bulked up legs.

Aerobic activity will not fix a skinny lower body.

Make-Believe Walking

When people hold onto a treadmill at high inclines and fast speeds, their hands are either on the bar in front or clutching the top of the console.

This makes their body tilt backwards at about the same angle as the incline, which means that the incline is cancelled out. The image below depicts this.

If you walk an incline without holding on, your body will be vertical, forcing increased joint and muscle motion from the butt down – which is why walking up a hill is harder than walking on a flat surface.

Have you tried HIIT?

Dashing up hills or running inclines as fast as you can such that you’re exhausted within 15 to 30 seconds is anaerobic. Anaerobic exercise, by definition, cannot be sustained.

A 100 meter sprint on flat ground is another example.

Anaerobic activity, which includes high intensity interval training and weightlifting, taps into fast-twitch muscle fibers, which are designed for brief bursts of power (absolute speed, speed relative to other factors such as an incline or staircases, and moving heavy weight).

Hopefully you know by now that a sustained walk, whether on a treadmill or mountain trail, will not solve the problem of skinny legs.

To begin building muscle in your lower body, start doing HIIT: high intensity interval training.

Essentially this is alternating those 15-30 second bursts of maximal effort with a few minutes of slow moving recovery.

Because this article topic is about whether or not holding onto a treadmill at fast speeds and high inclines can build up leg muscle, I won’t go into detail about how to build lower extremity muscle with strength training.

I’ll just sum that up briefly but will also provide links to in-depth articles.

First, what not to do:

• Zillions of seated calf raises
• Walking around all day with “calf building” shoes
• Inner and outer thigh machine use

Now, what TO do:

• Squat (ideally the back version – barbell across the back)
• Deadlift
• Leg press
• Weighted stationary or walking lunge

Shutterstock/MilanMarkovic78, pressfoto

Ancillary exercises include the leg extension and hamstring curl. Though these are isolation moves, they can contribute to building mass, which is why it’s not uncommon to see bodybuilders on these machines.

Use the treadmill for cardiovascular training, which should include HIIT.

But do not hold on, as this sabotages your training and can cause many problems such as stalled weight loss, shoulder painloss of balance and bad posture.

Lorra Garrick is a former personal trainer certified through the American Council on Exercise. At Bally Total Fitness she trained women and men of all ages for fat loss, muscle building, fitness and improved health.