The hallmark maneuvers can be spotted along running trails, the sidelines of playing fields and the corners of any gym. There's the perennial touch-your-toes-and-kiss-your-knees move. The one where you twist from side to side until your arms go numb then accidentally smack a stunned passer-by. And, of course, endless variations on the arm pretzel — routine for many exercisers.

Stretching before exercise, after all, sounds like a good idea. Our P.E. teachers showed us the moves. Trainers seconded the notion. And that sinewy lady at the health club who looks to be in some sort of contortionist-training program sure looks like she knows what she's doing.

But some exercise scientists now say the purported benefits of stretching may be, well, a bit overstretched.

"It's one of those common practices that doesn't have any science behind it," says Dr. Julie Gilchrist, an injury-prevention researcher with the Centers for Disease Control and Prevention (CDC).

She was part of a team that combed six decades worth of fitness studies and found no evidence for the long-standing assumption that pre-exercise stretching heads off sprains, strains or pains. Nor does it appear to help you jump higher, run faster or otherwise boost performance in typical fitness endeavors, according to the CDC study, which appeared last year in the journal Medicine & Science in Sports & Exercise.

THOMAS JAMES HURST / THE SEATTLE TIMES Runner's stride Steady yourself with pole or back of chair and bring knee up to hip height. In a fluid motion, swing your leg backward, mimicking a runner's gait. Repeat several times then switch sides.

In other words, it's a waste of time.

Another recent report, this one by Dr. Ian Shrier, an epidemiologist at Sir Mortimer B. Davis-Jewish General Hospital in Montreal, took the CDC's findings a step further. He reported in the Journal of Clinical Sports Medicine that stretching immediately before a workout may actually hamper performance. Perhaps, some speculate, by producing tiny tears and sapping muscles.

Gym dreaders will surely be pleased having this new excuse to shorten their workout. Still, many fitness professionals aren't ready to skip their stretching routines.

Flexibility should be goal

Cedric Bryant, chief exercise physiologist for the American Council on Exercise (ACE), says he still stretches, just for different reasons. "Unfortunately, it turns out the role of stretching in preventing injuries has been overstated, but that's not the only reason you should stretch."

Flexibility, he moans, is already the "Rodney Dangerfield of fitness."

"People spend a lot of time on cardio and strength, but when it comes to the third component of fitness — flexibility — people don't give it the respect it deserves."

THOMAS JAMES HURST / THE SEATTLE TIMES Hanging squat Holding a pole or stable, high-backed chair, bend as far as you can at the waist, with legs straight but knees slightly soft. Then bend knees and squat down, keeping arms and back straight.

Consistent stretching, he says, maintains our range of motion as we get older. "That's something people don't think about until you reach up to put away the groceries and you suddenly can't reach above your shoulders."

The biggest question raised by the reports, says Bryant, who lives in Bellevue, is: If it's not a good idea to stretch before exercise, then when is a good time?

He suggests after exercising. He spends the last five minutes of his workouts cooling down and stretching — when his muscles are already warmed up and supple. Others, including Shrier, the Canadian researcher, recommend stretching at times unrelated to the rest of your exercise routine.

Peter Shmock, two-time Olympic shot-putter and Seattle fitness trainer, also sees flexibility as an end in itself. So he concocted a series of what he calls "active stretches" for clients at his Belltown gym, Club Zum.

The notion of stretching as grasping your ankles and pulling with all your might is old-fashioned and, he agrees with the CDC here, a big waste of time.

THOMAS JAMES HURST / THE SEATTLE TIMES Full-body winds Stand with arms and legs in an X position and a wooden dowel (a broomstick will suffice) held high. Clockwise from top left: Keeping arms straight and knees soft, tilt dowel to the right, then swing over top of head to the left. Bend at waist and knees and continue the circular motion, bringing dowel near the ground and back up on your right side.

"All stretching should be, really, is moving," he says.

So rather than having a client kick her heel to her bottom and hold it there — he'll have her slowly mimic a runner's stride.

"Stretching should not be about pushing yourself to see how far you can bend," he says. "It's simply regaining the natural use of your limbs."

Whether you're in the Gumby camp or not, the most important thing, fitness experts agree, is warming up. That means jog slowly before you run. Pedal around a bit on flat ground before you take your bike up a mountain. And do a few squats before you pile on the weight.

The point is to get the blood flowing and your muscles engaged so whatever exercise comes next doesn't come as a complete shock to your body.

Listen to your body

Even the CDC study doesn't go as far as to say: Stop stretching. Instead, it offers this equivocal advice: "We can recommend neither the endorsement nor the discontinuation of stretching."

Uh, thanks.

In a nutshell: The federal government's take is if you're already stretching, keep doing it. If you're not, don't start now.

That's not as utterly useless as it may sound, says ACE's Bryant.

"There's a kind of kinesthetic intuition that's hard to measure in some study," he says. For some people, stretching their hamstrings or their Achilles tendons allows them to feel right. Those people probably already do it, and you couldn't get them to stop if you tried. But if you're one of those people who doesn't feel like you're getting anything out of pre-exercise stretches, and you're going through the motions simply because someone told you to once upon a time, you can probably abandon it.

Seattle's Jim Dow, for instance, spends 15 minutes on a stretching routine that includes wrapping his torso around a giant ball and unfolding his limbs with rubber bands before running or weight-lifting at least five times a week. And he's not about to quit.

"Every time I hurt myself and end up limping around for a week, it's when I haven't stretched before jumping into some movement," says the 47-year-old general contractor.

"I don't care what the science says, I listen to my own body."

Julia Sommerfeld: 206-464-2708 or jsommerfeld@seattletimes.com