A man does chin-ups at a city park

A man does chin-ups at a city park (Anatolii Stepanov, Reuters / April 30, 2012)

NEW YORK (Reuters) - From jumping rope to swinging a kettle bell to pounding a treadmill, a finely-tuned form can spell the difference between a sound body and a sore knee.

Experts say often a professional tweak can go a long way towards firming up your workout.

"People usually injure themselves on basic exercises, like a squat or a bench press," said New York-based personal trainer Tiffany Boucher.

But Boucher, who works for the national chain of fitness centers Equinox, said form is relatively easy to fix.

"Something is being overused, usually in tandem with some type of muscle imbalance," she said. "So it's often about getting people to put their shoulders in a certain place, find their center of gravity, engage their abdominals, or tilt their pelvis in a certain direction."

She said even a small adjustment can be transformative.

Knees are the most common focus of client complaint, according to Boucher. Once form is corrected, relief often comes within weeks.

"People don't have that continued inflammation," she said.

Dr. Daniel Solomon, a spokesperson for the American Academy of Orthopaedic Surgeons, believes in getting the help of a professional trainer before embarking on a new routine.

"Most of what we see are strains and really preventable muscle-type injuries," said Solomon, a California-based physician specializing in sports medicine. "People just do things their bodies aren't ready to do or capable of sustaining for long."

Another big mistake is skipping the warm up.

"They jump right in instead of spending 15 minutes to do a good cardio warm up and stretching before grabbing the weight," he said.

He said some workouts just require more expertise than others.

"I'm a proponent of using free weights," he said. "But you've got to make sure you have the technique correct."

Jessica Matthews, an exercise physiologist for the American Council on Exercise, said many highly effective workouts, such as kettle bells, medicine balls, and plyometric (jumping) moves, can be dangerous if done incorrectly.

"Some workouts are trickier," said Matthews, who is based in San Diego, California. "I've seen a lot of people use free weights incorrectly. There is a much greater margin of error than with machines, which move on a fixed path."

Before going all-out on the plyometric training that characterizes so many home DVD workouts, she said it's important to learn to land safely, which means softly and on the mid-foot.

"The body is one big kinetic chain. Dysfunction in one area will create dysfunction in another," she said. "So suddenly your hip is bothering you because of instability in your ankle."

Before tackling the latest high-intensity, technique-based workout, Matthews advises strengthening your stability and mobility through back-to-basic exercises such as plank, side plank, lunges and squats.

"Build that solid foundation first," she said. "Then progress to more explosive workouts that take more advanced skills."

If don't have your own personal trainer, Boucher said, don't hesitate to ask a fitness professional at your gym to observe your form for a few seconds. Then be open to the feedback.

"Do you hunch your shoulders? Hunch your back? " she said. "Maybe one side of your body is tighter than the other. Or the left hip is more rotated than the right."

"Sometimes it's that little thing that you can't catch on your own," she said.

(Editing by Patricia Reaney)