Fitness buff Adam Marelli admits he never paid much attention to form in his workouts.
Adam says, "I wanted to get through the numbers, when I wasn't doing like a full extension of a sit-up, a full range of motion in a pull-up, or in a push-up."
But once trainer Tracy Berman showed adam how to do his exercises right, he felt a difference.
Adam admits, "I was tired. It took, it took a while of getting used to."
Berman says, "Two of the major problems with doing exercises incorrectly are that 'A,' you're increasing your risk of injury, and 'B,' you're actually not working the muscles you're trying to work."
One frequent mistakes is with lunges - don't let your knee drift over your toe.
"And when you're doing this improperly, there's just so much stress on the knee and the lower back, which we obviously want to avoid," Berman says. "Push back. So, instead, you'll take a bigger step forward. Good, there you go. So you can see, it's a straight line down and a straight line here."
Pushups also need a straight line, but most people don't do it.
Instead, keep your body firm and flat, and bend only at the elbows.
And when it comes to sit-ups, forget about the crunch.
Berman says, "So coming a little bit farther up from the floor than a crunch and not all the way up, so your elbows shouldn't be touching your knees."
She says form should always top repetitions.
"So even if you can only get to thirteen, but the thirteen are perfect, then do thirteen perfect, rather than twenty all over the place," she says.
To help, Berman suggests practicing the correct form in a mirror, until the moves come naturally.