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Flexing your arm to lift a weight seems like a simple maneuver, but you might be doing it wrong.
Whether you use a large and complicated system of pulleys and weights to work out, or stick to running and calisthenics, knowing the correct way to exercise is important. Incorrectly performed exercise can mean you're not getting the benefits you're looking for, and can even lead to injury.
"There's almost always a safer alternative to a risky exercise," said Stephen Ball, an associate professor of nutrition and exercise physiology at the University of Missouri. He's created a series of videos that show how to exercise safely.
Here are seven exercises people commonly do incorrectly, and how to do them right.
Standing quad stretchSlide 2 of 15
Standing quad stretch
Though pulling your leg up behind you to stretch your quadriceps seems innocent enough, overflexing the knee that way puts a lot of unnecessary stress on the joint.
"It's very popular, but it's a risky exercise," Ball said, because it can wear out the knees over time and lead to a lot of pain down the road.
Instead, Ball recommended stretching your quads with the kneeling quad stretch. This involves kneeling on both knees and reaching back to touch each ankle in turn, or kneeling on one knee at a time and leaning forward to stretch the quadriceps. Ball said these techniques stretch the quads without hurting the joints.Slide 3 of 15
Squats liftsSlide 4 of 15
A classic lift done in muscle-building workouts, squats require a lot of focus on form and movement to do correctly.
"Never hyperflex or hyperextend your knees," Ball said. Locking your knees upon standing hyperextends the knees, and squatting so deeply that your calf is pressed against the back your thigh hyperflexes the knee, he said.
Hyperflexing and extending create tiny tears, called microtraumas, in joints, which can go unnoticed. "People might do this and never have a problem," Ball said, "but over time, microtraumas can lead to wearing out of joints.
In addition, people frequently try to lift too much weight when they do deep squats, which makes proper form more difficult to maintain, Ball said.Slide 5 of 15
Bench pressSlide 6 of 15
The bench press is possibly the most frequently performed weight lifting exercise at the gym, Ball said. It's popular because the amount of weight a person can bench is an often-cited measure of strength, and because it builds beach muscles such as the pectorals and biceps.
But quite commonly, weight lifters put too much weight on the bar and arch their backs, which puts dangerous stress on the connective tissue of the back and neck, and further, doesn't efficiently work the muscle the exercise is supposed to strengthen, Ball said.
The back, neck and knee joints are particularly vulnerable over time to problems caused by exercise, he said, adding that around 80 percent of people have some sort of back pain during their lives.Slide 7 of 15
Seated pull-downSlide 8 of 15