Most runners have a love-hate relationship with the treadmill. On the one hand, it's boring and germ-infested. On the other, it's often a necessary evil to get through long winters or rainy mornings.

With any luck, today, on National Running Day, you'll be able to celebrate out of doors, in all of this early-June glory. Working out outside has noted benefits over hitting the gym, including improved energy and a greater likelihood to keep exercising.

But in case you're stuck inside -- and for the indoor runs in your future -- we want to make sure you're doing it right. We asked three fitness experts -- personal trainer Matthew Basso, president of Iron Lotus Personal Training; Jason Karp, Ph.D., an exercise physiologist and the author of Running for Women and Running a Marathon For Dummies and Jay Cardiello, celebrity trainer, author and creator of JCore -- to share their biggest treadmill pet peeves. Below are some of the most common mistakes they see gymgoers make, and what we should be doing instead.

You Crane Your Neck To Watch TV (Or Your Feet)

Anything that throws off your posture, whether it be hunching over to watch your feet or leaning to the left for a better view of the TV, is generally a bad idea. "Your neck is pulled to the right or dropped forward and one part of the musculature is getting stretched while another is getting tightened," says Basso. The longer you're in that position, the higher your risk of injury becomes, he says.

You're also likely to offset your balance, warns Karp. "You're looking to the left or to the right and your body's going to follow a little bit," he says.

Slumping over can also limit your oxygen intake, says Cardiello. To guarantee you're standing your tallest, imagine someone is pouring ice water down your spine, he says.

For those runners who rely on a little screen time at the gym, try to find a treadmill with a screen attached, says Cardiello, so you can face forward with your chin parallel to the ground. If your gym isn't equipped with those machines, head to the back of the room. That will keep your neck as straight as possible while still allowing you to watch overhead TVs, he says. "Keep your head, heart and hips inline when you run," he says. "You're running over the ground, never into the ground." Or the belt, as the case may be.

You're Too Zoned Out

Clearing your mind with your favorite TV show during your run is one thing. Jumping on the treadmill with concrete fitness goals is another. "I think a lot of people who choose to use cardio equipment, yeah, they sweat, but your mind starts to wander," says Basso. "Instead of really being present and focusing on the exercise, your gait, your posture, people lose it there." A too-engrossing book or magazine, or a movie might be too distracting, says Cardiello. "Save the reading for your cooldown."

You Do The Same Thing Over And Over

"One of the biggest mistakes people make [at the gym] is to do the exact same thing every time, and then wonder why they don't see results," says Karp. So shake things up, by varying the intensity, speed or incline. Try a longer and slower run one day, and a shorter and faster one on another visit, he says.

A great way to mix things up and see results sooner is with an interval workout, says Cardiello. Short bursts of higher intensity exercise can up the fat-burning powers of your workouts, improve heart health and more, not to mention save you some time.

And you might also want to consider adding in a little sideways movement, says Basso. Unless you're really coordinated, don't attempt to walk backwards or do anything too fancy on a treadmill. But most people -- at a slow pace -- can handle some lateral shuffling or crossover steps, he says, to work yours muscles in different ways.

You Skip The Warmup

Yes, you're busy. Some days you just want to hop on the treadmill, get it over with and get out. But skipping a warmup can lead to pain and injuries, says Basso. You don't need a lot of time, and you don't need to passively stretch, he says. Instead, take five to seven minutes for an active warmup with a "joint-by-joint approach," he says, that includes hip circles, toe touches and more. "It's more of a priority to keep your mobility and keep yourself out of pain than to start a workout," he says.

You Hold The Bars

Holding onto the handrails on the treadmill might seem like a safety measure, but your workout will suffer, says Karp. Some of your bodyweight will be supported, meaning you won't have to work as hard and you won't burn as many calories, he explains. If you feel like you need to hold on, it's probably because you're going at a slightly faster speed than you're ready for, he says. "Get comfortable without holding on in increments to gain confidence at each speed," he suggests.

You Set The Incline Too Steep

How often do you encounter a steep hill in the outside world that takes you an hour to climb? Exactly. Exercise should be functional, says Basso, and strengthen your muscles for real-world use. Plus, the steeper that incline, the more likely you'll be holding onto the bar to keep yourself on the belt. "If you have to hold on, it's either too fast or too steep," says Karp.

You Trust The Settings

Between the heart-rate monitor grips on the handrail and the button for the "fat-burning" zone, there's not much worth trusting on that digital dashboard. "You can't really rely on those," says Karp. "The mathematical formulas are rough estimates based on a lot of variables," he says. And every runner is different. Since they're probably not accurate to begin with, says Cardiello, don't obsess over the numbers on your machine. "Throw a towel over the display," he says, and you might just find you work a little harder.

You Jump Off With The Belt Moving At Full Speed

It might seem like taking a water break without slowing down the belt saves you time in the longrun, but not if it makes you trip and fall first. "Most people don't have the coordination to do that without risking injury," says Karp. "I see people all the time who come close to falling."