Keep these vital parts of your body healthy

by Ted Spiker

The powerhouse muscles of our hips and thighs drive us forward, ensure we land safely, and help keep our knees and feet in proper working order. To handle such a big job, hamstrings, quadriceps, and glutes need to be in top form. Here's how to keep them healthy

Runners know how to rank their body parts. Most vulnerable? Knees, for sure. Most tortured? Feet. We've got the blisters and black toenails to prove it. Most powerful? When it comes to speed, endurance, and the diesel that gets us uphill, downhill, and everywhere in between, most of us would find it hard to credit anything other than our thighs. And for good reason. The powerhouse muscles that make up our upper legs drive our running--whether we're sprinting 100 yards or battling through 26.2.

Run enough hills and you'll develop an appreciation for the demands on your hamstrings (which power you up) and quadriceps (which steady you down). Three muscles make up the mighty hamstrings, which run down the back of the thigh and bend the knee and extend the leg at the hip. The quadriceps, on the front of the thigh, comprise four muscles that extend and stabilize the knee and decelerate the forces of impact when we land. Unlike most muscles, the hamstrings and the quadriceps cross two joints--the hip and the knee--which means that they assist with the function of both, making an injury to either muscle group extremely disruptive to running, says Brian Krabak, M.D., a sports-medicine and rehabilitation specialist at Johns Hopkins University. Both can be strained (or pulled) if they are overextended to the point that they rip slightly. A complete tear of the muscle is called a rupture (ouch!). These injuries usually come after a burst of speed, and with a popping sound or sensation. Overtraining, forceful stretching, excessive speedwork, or speedwork without a proper warmup can strain a muscle. Strength imbalances can also pose a threat. If the front of your leg is stronger than the back of your leg (this is especially common among triathletes and runners who cycle), the quadriceps can put extra strain on the hamstrings.

But even if you take great care of your hamstrings and quadriceps--regularly stretching, strengthening, and massaging--they won't necessarily be complaint-free. That's because the source of a lot of thigh issues often isn't in the legs at all. You have to go higher. "Many thigh injuries can be traced back to weak hip muscles, such as the gluteal muscles," Dr. Krabak says. The gluteus maximus and gluteus medius are the two large muscles in the buttocks that propel you forward and support the hip joint and the pelvis while running. "As soon as your foot hits the ground, your glutes should fire first, followed by hamstrings and then quadriceps," says Nancy Cummings, a certified strength and conditioning specialist, athletic trainer, and assistant professor of physical education and athletic training at Florida Southern College. "If the glutes aren't strong enough to activate, the quads and hamstrings will have to pick up the slack. This throws off the alignment and mechanics of the entire leg and can lead to knee and foot problems."

If you've ever had Iliotibial Band syndrome (ITBS), you've experienced this trickle-down effect--probably without realizing it. Runners who develop ITBS tend to curse their knees because that's where they feel the pain. But weak glutes are often responsible. The iliotibial band runs from the pelvis down the side of the thigh to the knee, so when it's stressed, pain can radiate anywhere along its path--the glute, hip, thigh, or knee.

Piriformis syndrome is what Dr. Krabak calls "a catchy phrase for a pain in the butt." The Piriformis Muscle lies deep in your buttocks--so hidden that many runners don't even know it's there. But if you overtrain and understretch, the piriformis can become so tight that it'll restrict leg movement and irritate the sciatic nerve (the largest nerve in the body, responsible for motor and sensory function in the legs). Some older runners may experience hip pain due to osteoarthritis, the loss of cartilage in the joint. And others (especially women with low bone density) can be prone to stress fractures in the thigh or hip bones.

The majority of upper-leg issues in runners result from lack of strength and flexibility--with a dose of overuse and sudden changes in training. Fortunately, most of these problems are preventable, says Dr. Krabak, by following smart training tactics, namely, listening to your body and backing off when necessary. As extra insurance, work to strengthen your quadriceps, hamstrings, and glutes.