3 Common Workout Mistakes To Avoid This Year (VIDEO)

If you vowed to get in better shape this year, you may have adopted a new workout routine or stepped up your old one to try to make good on that promise. It's a goal that can make a huge difference in your life -- if you're doing your exercises correctly. Some of the most common workout mistakes don't just undermine your efforts; they can actually cause injury -- certainly not a good way to start out a new year.

Fitness expert Jessica Matthews recently stopped by the web series #OWNSHOW to explain three of the more common workout mistakes and share her tips for how to stay injury- and pain-free while you get in shape.

Mistake #1: Using a weight that's too heavy

While you do want to use a weight that challenges and tires your muscles, you don't want to choose something that ends up compromising your form.

"When doing an exercise like bicep curls... the proper form is to do this: Actually let the biceps, the muscles of your arms, do the work," Matthews says while demonstrating in the above video. "If we're using too heavy of a weight, we may see improper form, like using momentum to complete the movement. Our back now is involved, and that can lead to back pain down the road."

Listen closely to your body, she adds. "If you find that your form is suffering, that may be your body giving you a cue to decrease the amount of weight you're using," Matthews says. "We do want to be fatigued or challenged by the last one or two repetitions that we're doing, [but] we want to make sure we're doing all our repetitions with proper form."

When is it time to move to a heavier weight? Matthews explains that here.

Mistake #2: Targeting the same body part each workout

It may be tempting to focus exclusively on the one area you're most desperate to improve upon, but targeting one body part day after day is an over-exercising mistake Matthews urges people to avoid.

"Muscles need time to rest and recover," she says. "If I, say, train my biceps on one day, I want to allow at least 48 hours before I would target that same muscle again. This is going to allow time for recovery, and that's where our results really come from."

Mistake #3: Running as your only form of exercise

Cardio is great. And consistency is good... right? Not quite, Matthews explains.

"I know some people out there may love to do something like running. Every day, you want to go out for a run. That's great, but the problem is running provides the same exact stress to the body over and over and over again," she says.

Instead, Matthews suggests varying your workout routine to keep from getting injured -- or bored. "It's important that we do what's called 'cross-training,'" she says. "That means mixing in other forms of activity, like swimming or using the elliptical and strength-training, in addition to, say, running, if that's your activity of choice."

Same Workout, Way Better Results