What's a hip flexor and why can't I work it?

This is the sit-up law of the land. Break it and you risk public correction by trainers, instructors, even complete strangers.

Recently overhearing just such an exchange sparked a question: what exactly is a hip flexor, and why is this area seemingly the only place on our bodies we're not supposed to work?

A grouping of hip muscles on the front of the body, hip flexors make it possible to walk, kick, run or simply lift your leg, says Joann Flannery-Mathers, a personal trainer and owner of Personal Fitness, a physical fitness and counseling business in Joliet.

And "Yes, you do want to work your hip flexors," she said, "strong hip flexors make it easier to walk, climb up hills or climb up and down stairs, and having strong hip flexors actually helps strengthen the quadriceps because they're connected."

However, according to Alison Huntley, program director and a personal trainer at Waukegan's Lake County Family YMCA, most people will be able to keep those muscles conditioned with a regular workout.

"You don't really have to specifically work them because they're pretty strong already," Huntley said. "You definitely want to maintain flexibility in that group of muscles, but unless you're an athlete training for something specific or you're doing some rehab work, there really isn't any reason you would want to strengthen that muscle group alone."

Steve Allen, fitness director at the Center Club in Libertyville, agreed, noting that "For the average person, hip flexor strength isn't as much of an issue as abdominals. Most people need to work abdominals to get them strong; it's very rare that you have a hip flexor weakness that's causing any problems." Allen said elderly people who are inactive and anyone who sits a lot can lose strength and flexibility in the hip flexors, which, over time, can lead to posture problems.

"But any hip flexor exercise is totally dependent on abdominal strength to stabilize the pelvis," he warned. "To do [a hip flexor exercise] correctly and safely, you have to have strong enough abdominals."

Flannery-Mathers, who agreed there's not much benefit in trying to isolate hip flexors, said some easy exercises that will also work the quadriceps and abdominals include standing knee raises, in which you stand and lift one knee toward the chest, and single leg lifts, in which you lie on your back with one leg bent and lift the straight leg to the height of the bent knee. Each exercise should be performed 15 to 20 times per leg.

More advanced exercises, which require very strong abdominals to protect the low back, include hanging knee raises and hanging straight leg raises, which are performed while hanging vertically with your weight supported by the forearms, and regular leg lifts, performed while lying down.

Incidentally, trying to work hip flexors by doing a full sit-up "is probably not the best way to do it because of the stress it puts on the back," Flannery-Mathers said.

© Copyright 1994 Paula Lauer